fstrim

title: fstrim(8)

text:
# fstrim(8)

## NAME
fstrim - discard unused blocks on a mounted filesystem

## SYNOPSIS
fstrim [-Aav] [-o offset] [-l length] [-m minimum-size] [mountpoint]

## DESCRIPTION
fstrim is used on a mounted filesystem to discard (or "trim") blocks which are not in use by the filesystem. This is useful for solid-state drives (SSDs) and thinly-provisioned storage.

By default, fstrim will discard all unused blocks in the filesystem. Options may be used to modify this behavior based on range or size, as explained below.

The mountpoint argument is the pathname of the directory where the filesystem is mounted and is required when -A, -a, --fstab, or --all are unspecified.

Running fstrim frequently, or even using mount -o discard, might negatively affect the lifetime of poor-quality SSD devices. For most desktop and server systems a sufficient trimming frequency is once a week. Note that not all devices support a queued trim, so each trim command incurs a performance penalty on whatever else might be trying to use the disk at the time.

## OPTIONS
The offset, length, and minimum-size arguments may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.

-A, --fstab

Trim all mounted filesystems mentioned in /etc/fstab on devices that support the discard operation. The root filesystem is determined from kernel command line if missing in the file. The other supplied options, like --offset, --length and --minimum, are applied to all these devices. Errors from filesystems that do not support the discard operation, read-only devices, autofs and read-only filesystems are silently ignored. Filesystems with "X-fstrim.notrim" mount option are skipped.

-a, --all

Trim all mounted filesystems on devices that support the discard operation. The other supplied options, like --offset, --length and --minimum, are applied to all these devices. Errors from filesystems that do not support the discard operation, read-only devices and read-only filesystems are silently ignored.

-n, --dry-run

This option does everything apart from actually call FITRIM ioctl.

-o, --offset offset

Byte offset in the filesystem from which to begin searching for free blocks to discard. The default value is zero, starting at the beginning of the filesystem.

-l, --length length

The number of bytes (after the starting point) to search for free blocks to discard. If the specified value extends past the end of the filesystem, fstrim will stop at the filesystem size boundary. The default value extends to the end of the filesystem.

-I, --listed-in list

Specifies a colon-separated list of files in fstab or kernel mountinfo format. All missing or empty files are silently ignored. The evaluation of the list stops after first non-empty file. For example: --listed-in /etc/fstab:/proc/self/mountinfo.

Filesystems with "X-fstrim.notrim" mount option in fstab are skipped.

-m, --minimum minimum-size

Minimum contiguous free range to discard, in bytes. (This value is internally rounded up to a multiple of the filesystem block size.) Free ranges smaller than this will be ignored and fstrim will adjust the minimum if it’s smaller than the device’s minimum, and report that (fstrim_range.minlen) back to userspace. By increasing this value, the fstrim operation will complete more quickly for filesystems with badly fragmented freespace, although not all blocks will be discarded. The default value is zero, discarding every free block.

-t, --types list

Specifies allowed or forbidden filesystem types when used with --all or --fstab. The list is a comma-separated list of the filesystem names. The list follows how mount -t evaluates type patterns. Only specified filesystem types are allowed. All specified types are forbidden if the list is prefixed by "no" or each filesystem prefixed by "no" is forbidden. If the option is not used, then all filesystems (except "autofs") are allowed.

-v, --verbose

Verbose execution. With this option fstrim will output the number of bytes passed from the filesystem down the block stack to the device for potential discard. This number is a maximum discard amount from the storage device’s perspective, because FITRIM ioctl called repeated will keep sending the same sectors for discard repeatedly. fstrim will report the same potential discard bytes each time, but only sectors which had been written to between the discards would actually be discarded by the storage device. Further, the kernel block layer reserves the right to adjust the discard ranges to fit raid stripe geometry, non-trim capable devices in a LVM setup, etc. These reductions would not be reflected in fstrim_range.len (the --length option).

--quiet-unsupported

Suppress error messages if trim operation (ioctl) is unsupported. This option is meant to be used in systemd service file or in cron(8) scripts to hide warnings that are result of known problems, such as NTFS driver reporting Bad file descriptor when device is mounted read-only, or lack of file system support for ioctl FITRIM call. This option also cleans exit status when unsupported filesystem specified on fstrim command line.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## EXIT STATUS
0

success

1

failure

32

all failed

64

some filesystem discards have succeeded, some failed

The command fstrim --all returns 0 (all succeeded), 32 (all failed) or 64 (some failed, some succeeded).

## AUTHORS
Lukas Czerner <lczerner@redhat.com>, Karel Zak <kzak@redhat.com>

## SEE ALSO
blkdiscard(8), mount(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The fstrim command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


isosize

package: util-linux

title: isosize(8)

text:
# isosize(8)

## NAME
isosize - output the length of an iso9660 filesystem

## SYNOPSIS
isosize [options] iso9660_image_file

## DESCRIPTION
This command outputs the length of an iso9660 filesystem that is contained in the specified file. This file may be a normal file or a block device (e.g. /dev/hdd or /dev/sr0). In the absence of any options (and errors), it will output the size of the iso9660 filesystem in bytes. This can now be a large number (>> 4 GB).

## OPTIONS
-x, --sectors

Show the block count and block size in human-readable form. The output uses the term "sectors" for "blocks".

-d, --divisor number

Only has an effect when -x is not given. The value shown (if no errors) is the iso9660 file size in bytes divided by number. So if number is the block size then the shown value will be the block count. The size of the file (or block device) holding an iso9660 filesystem can be marginally larger than the actual size of the iso9660 filesystem. One reason for this is that cd writers are allowed to add "run out" sectors at the end of an iso9660 image.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## EXIT STATUS
0

success

1

generic failure, such as invalid usage

32

all failed

64

some failed

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The isosize command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


ldattach

title: ldattach(8)

text:
# ldattach(8)

## NAME
ldattach - attach a line discipline to a serial line

## SYNOPSIS
ldattach [-1278denoVh] [-i iflag] [-s speed] ldisc device

## DESCRIPTION
The ldattach daemon opens the specified device file (which should refer to a serial device) and attaches the line discipline ldisc to it for processing of the sent and/or received data. It then goes into the background keeping the device open so that the line discipline stays loaded.

The line discipline ldisc may be specified either by name or by number.

In order to detach the line discipline, kill(1) the ldattach process.

With no arguments, ldattach prints usage information.

## LINE DISCIPLINES
Depending on the kernel release, the following line disciplines are supported:

TTY(0)

The default line discipline, providing transparent operation (raw mode) as well as the habitual terminal line editing capabilities (cooked mode).

SLIP(1)

Serial Line IP (SLIP) protocol processor for transmitting TCP/IP packets over serial lines.

MOUSE(2)

Device driver for RS232 connected pointing devices (serial mice).

PPP(3)

Point to Point Protocol (PPP) processor for transmitting network packets over serial lines.

STRIP(4); AX25(5); X25(6)

Line driver for transmitting X.25 packets over asynchronous serial lines.

6PACK(7); R3964(9)

Driver for Simatic R3964 module.

IRDA(11)

Linux IrDa (infrared data transmission) driver - see <http://irda.sourceforge.net/>

HDLC(13)

Synchronous HDLC driver.

SYNC_PPP(14)

Synchronous PPP driver.

HCI(15)

Bluetooth HCI UART driver.

GIGASET_M101(16)

Driver for Siemens Gigaset M101 serial DECT adapter.

PPS(18)

Driver for serial line Pulse Per Second (PPS) source.

GSM0710(21)

Driver for GSM 07.10 multiplexing protocol modem (CMUX).

## OPTIONS
-1, --onestopbit

Set the number of stop bits of the serial line to one.

-2, --twostopbits

Set the number of stop bits of the serial line to two.

-7, --sevenbits

Set the character size of the serial line to 7 bits.

-8, --eightbits

Set the character size of the serial line to 8 bits.

-d, --debug

Keep ldattach in the foreground so that it can be interrupted or debugged, and to print verbose messages about its progress to standard error output.

-e, --evenparity

Set the parity of the serial line to even.

-i, --iflag value...

Set the specified bits in the c_iflag word of the serial line. The given value may be a number or a symbolic name. If value is prefixed by a minus sign, the specified bits are cleared instead. Several comma-separated values may be given in order to set and clear multiple bits.

-n, --noparity

Set the parity of the serial line to none.

-o, --oddparity

Set the parity of the serial line to odd.

-s, --speed value

Set the speed (the baud rate) of the serial line to the specified value.

-c, --intro-command string

Define an intro command that is sent through the serial line before the invocation of ldattach. E.g. in conjunction with line discipline GSM0710, the command 'AT+CMUX=0\r' is commonly suitable to switch the modem into the CMUX mode.

-p, --pause value

Sleep for value seconds before the invocation of ldattach. Default is one second.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## AUTHORS
Tilman Schmidt <tilman@imap.cc>

## SEE ALSO
inputattach(1), ttys(4)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The ldattach command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


lslocks

title: lslocks(8)

summary: list local system locks

text:
# lslocks(8)

## NAME
lslocks - list local system locks

## SYNOPSIS
lslocks [options]

## DESCRIPTION
lslocks lists information about all the currently held file locks in a Linux system.

Note that lslocks also lists OFD (Open File Description) locks, these locks are not associated with any process (PID is -1). OFD locks are associated with the open file description on which they are acquired. This lock type is available since Linux 3.15, see fcntl(2) for more details.

## OPTIONS
-b, --bytes

Print the sizes in bytes rather than in a human-readable format. By default, the unit, sizes are expressed in, is byte, and unit prefixes are in power of 2^10 (1024). Abbreviations of symbols are exhibited truncated in order to reach a better readability, by exhibiting alone the first letter of them; examples: "1 KiB" and "1 MiB" are respectively exhibited as "1 K" and "1 M", then omitting on purpose the mention "iB", which is part of these abbreviations.

-i, --noinaccessible

Ignore lock files which are inaccessible for the current user.

-J, --json

Use JSON output format.

-n, --noheadings

Do not print a header line.

-o, --output list

Specify which output columns to print. Use --help to get a list of all supported columns. The default list of columns may be extended if list is specified in the format +list (e.g., lslocks -o +BLOCKER).

--output-all

Output all available columns.

-p, --pid pid

Display only the locks held by the process with this pid.

-r, --raw

Use the raw output format.

-u, --notruncate

Do not truncate text in columns.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## OUTPUT
COMMAND

The command name of the process holding the lock.

PID

The process ID of the process which holds the lock or -1 for OFDLCK.

TYPE

The type of lock; can be FLOCK (created with flock(2)), POSIX (created with fcntl(2) and lockf(3)) or OFDLCK (created with fcntl(2)).

SIZE

Size of the locked file.

MODE

The lock’s access permissions (read, write). If the process is blocked and waiting for the lock, then the mode is postfixed with an '*' (asterisk).

M

Whether the lock is mandatory; 0 means no (meaning the lock is only advisory), 1 means yes. (See fcntl(2).)

START

Relative byte offset of the lock.

END

Ending offset of the lock.

PATH

Full path of the lock. If none is found, or there are no permissions to read the path, it will fall back to the device’s mountpoint and "..." is appended to the path. The path might be truncated; use --notruncate to get the full path.

BLOCKER

The PID of the process which blocks the lock.

## NOTES
The lslocks command is meant to replace the lslk(8) command, originally written by Victor A. Abell <abe@purdue.edu> and unmaintained since 2001.

## AUTHORS
Davidlohr Bueso <dave@gnu.org>

## SEE ALSO
flock(1), fcntl(2), lockf(3)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The lslocks command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


lsns

title: lsns(8)

summary: list namespaces

text:
# lsns(8)

## NAME
lsns - list namespaces

## SYNOPSIS
lsns [options] namespace

## DESCRIPTION
lsns lists information about all the currently accessible namespaces or about the given namespace. The namespace identifier is an inode number.

The default output is subject to change. So whenever possible, you should avoid using default outputs in your scripts. Always explicitly define expected output mode (--tree or --list) and columns by using the --output option together with a columns list in environments where a stable output is required.

The NSFS column, printed when net is specified for the --type option, is special; it uses multi-line cells. Use the option --nowrap to switch to ","-separated single-line representation.

Note that lsns reads information directly from the /proc filesystem and for non-root users it may return incomplete information. The current /proc filesystem may be unshared and affected by a PID namespace (see unshare --mount-proc for more details). lsns is not able to see persistent namespaces without processes where the namespace instance is held by a bind mount to /proc/pid/ns/type.

## OPTIONS
-J, --json

Use JSON output format.

-l, --list

Use list output format.

-n, --noheadings

Do not print a header line.

-o, --output list

Specify which output columns to print. Use --help to get a list of all supported columns. The default list of columns may be extended if list is specified in the format +list (e.g., lsns -o +PATH).

--output-all

Output all available columns.

-P, --persistent

Display only the namespaces without processes (aka persistent namespaces), created by bind mounting /proc/pid/ns/type files to a filesystem path.

-p, --task PID

Display only the namespaces held by the process with this PID.

-r, --raw

Use the raw output format.

-t, --type type

Display the specified type of namespaces only. The supported types are mnt, net, ipc, user, pid, uts, cgroup and time. This option may be given more than once.

-u, --notruncate

Do not truncate text in columns.

-W, --nowrap

Do not use multi-line text in columns.

-T, --tree rel

Use tree-like output format. If process is given as rel, print process tree(s) in each name space. This is default when --tree is not specified. If parent is given, print tree(s) constructed by the parent/child relationship. If owner is given, print tree(s) constructed by the owner/owned relationship. owner is used as default when rel is omitted.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## EXIT STATUS
The lsns utility exits with one of the following values:

0

Success.

1

General error.

2

An ioctl was unknown to the kernel.

## AUTHORS
Karel Zak <kzak@redhat.com>

## SEE ALSO
nsenter(1), unshare(1), clone(2), namespaces(7), ioctl_ns(2), ip-netns(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The lsns command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


mkfs

title: mkfs(8)

summary: build a Linux filesystem

text:
# mkfs(8)

## NAME
mkfs - build a Linux filesystem

## SYNOPSIS
mkfs [options] [-t type] [fs-options] device [size]

## DESCRIPTION
This mkfs frontend is deprecated in favour of filesystem specific mkfs.<type> utils.

mkfs is used to build a Linux filesystem on a device, usually a hard disk partition. The device argument is either the device name (e.g., /dev/hda1, /dev/sdb2), or a regular file that shall contain the filesystem. The size argument is the number of blocks to be used for the filesystem.

The exit status returned by mkfs is 0 on success and 1 on failure.

In actuality, mkfs is simply a front-end for the various filesystem builders (mkfs.fstype) available under Linux. The filesystem-specific builder is searched for via your PATH environment setting only. Please see the filesystem-specific builder manual pages for further details.

## OPTIONS
-t, --type type

Specify the type of filesystem to be built. If not specified, the default filesystem type (currently ext2) is used.

fs-options

Filesystem-specific options to be passed to the real filesystem builder.

-V, --verbose

Produce verbose output, including all filesystem-specific commands that are executed. Specifying this option more than once inhibits execution of any filesystem-specific commands. This is really only useful for testing.

-h, --help

Display help text and exit.

-V, --version

Print version and exit. (Option -V will display version information only when it is the only parameter, otherwise it will work as --verbose.)

## BUGS
All generic options must precede and not be combined with filesystem-specific options. Some filesystem-specific programs do not automatically detect the device size and require the size parameter to be specified.

## AUTHORS
David Engel <david@ods.com>, Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>, Ron Sommeling <sommel@sci.kun.nl>.

The manual page was shamelessly adapted from Remy Card’s version for the ext2 filesystem.

## SEE ALSO
fs(5), badblocks(8), fsck(8), mkdosfs(8), mke2fs(8), mkfs.bfs(8), mkfs.ext2(8), mkfs.ext3(8), mkfs.ext4(8), mkfs.minix(8), mkfs.msdos(8), mkfs.vfat(8), mkfs.xfs(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The mkfs command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


mkfs.cramfs

title: mkfs.cramfs(8)

summary: make compressed ROM file system

text:
# mkfs.cramfs(8)

## NAME
mkfs.cramfs - make compressed ROM file system

## SYNOPSIS
mkfs.cramfs [options] directory file

## DESCRIPTION
Files on cramfs file systems are zlib-compressed one page at a time to allow random read access. The metadata is not compressed, but is expressed in a terse representation that is more space-efficient than conventional file systems.

The file system is intentionally read-only to simplify its design; random write access for compressed files is difficult to implement. cramfs ships with a utility (mkcramfs(8)) to pack files into new cramfs images.

File sizes are limited to less than 16 MB.

Maximum file system size is a little under 272 MB. (The last file on the file system must begin before the 256 MB block, but can extend past it.)

## ARGUMENTS
The directory is simply the root of the directory tree that we want to generate a compressed filesystem out of.

The file will contain the cram file system, which later can be mounted.

## OPTIONS
-v

Enable verbose messaging.

-E

Treat all warnings as errors, which are reflected as command exit status.

-b blocksize

Use defined block size, which has to be divisible by page size.

-e edition

Use defined file system edition number in superblock.

-N big, little, host

Use defined endianness. Value defaults to host.

-i file

Insert a file to cramfs file system.

-n name

Set name of the cramfs file system.

-p

Pad by 512 bytes for boot code.

-s

This option is ignored. Originally the -s turned on directory entry sorting.

-z

Make explicit holes.

-l[=mode]

Use exclusive BSD lock for device or file it operates. The optional argument mode can be yes, no (or 1 and 0) or nonblock. If the mode argument is omitted, it defaults to "yes". This option overwrites environment variable $LOCK_BLOCK_DEVICE. The default is not to use any lock at all, but it’s recommended to avoid collisions with udevd or other tools.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## EXIT STATUS
0

success

8

operation error, such as unable to allocate memory

## SEE ALSO
fsck.cramfs(8), mount(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The mkfs.cramfs command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


mkswap

title: mkswap(8)

summary: set up a Linux swap area

text:
# mkswap(8)

## NAME
mkswap - set up a Linux swap area

## SYNOPSIS
mkswap [options] device [size]

## DESCRIPTION
mkswap sets up a Linux swap area on a device or in a file.

The device argument will usually be a disk partition (something like /dev/sdb7) but can also be a file. The Linux kernel does not look at partition IDs, but many installation scripts will assume that partitions of hex type 82 (LINUX_SWAP) are meant to be swap partitions. (Warning: Solaris also uses this type. Be careful not to kill your Solaris partitions.)

The size parameter is superfluous but retained for backwards compatibility. (It specifies the desired size of the swap area in 1024-byte blocks. mkswap will use the entire partition or file if it is omitted. Specifying it is unwise - a typo may destroy your disk.)

After creating the swap area, you need the swapon(8) command to start using it. Usually swap areas are listed in /etc/fstab so that they can be taken into use at boot time by a swapon -a command in some boot script.

## WARNING
The swap header does not touch the first block. A boot loader or disk label can be there, but it is not a recommended setup. The recommended setup is to use a separate partition for a Linux swap area.

mkswap, like many others mkfs-like utils, erases the first partition block to make any previous filesystem invisible.

However, mkswap refuses to erase the first block on a device with a disk label (SUN, BSD, ...).

## OPTIONS
-c, --check

Check the device (if it is a block device) for bad blocks before creating the swap area. If any bad blocks are found, the count is printed.

-f, --force

Go ahead even if the command is stupid. This allows the creation of a swap area larger than the file or partition it resides on. Also, without this option, mkswap will refuse to erase the first block on a device with a partition table.

-q, --quiet

Suppress output and warning messages.

-L, --label label

Specify a label for the device, to allow swapon(8) by label.

--lock[=mode]

Use exclusive BSD lock for device or file it operates. The optional argument mode can be yes, no (or 1 and 0) or nonblock. If the mode argument is omitted, it defaults to yes. This option overwrites environment variable $LOCK_BLOCK_DEVICE. The default is not to use any lock at all, but it’s recommended to avoid collisions with systemd-udevd(8) or other tools.

-p, --pagesize size

Specify the page size (in bytes) to use. This option is usually unnecessary; mkswap reads the size from the kernel.

-U, --uuid UUID

Specify the UUID to use. The default is to generate a UUID. The format of the UUID is a series of hex digits separated by hyphens, like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The UUID parameter may also be one of the following: clear

clear the filesystem UUID

random

generate a new randomly-generated UUID

time

generate a new time-based UUID

-e, --endianness ENDIANNESS

Specify the ENDIANNESS to use, valid arguments are native, little or big. The default is native.

-v, --swapversion 1

Specify the swap-space version. (This option is currently pointless, as the old -v 0 option has become obsolete and now only -v 1 is supported. The kernel has not supported v0 swap-space format since 2.5.22 (June 2002). The new version v1 is supported since 2.1.117 (August 1998).)

--verbose

Verbose execution. With this option mkswap will output more details about detected problems during swap area set up.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## ENVIRONMENT
LIBBLKID_DEBUG=all

enables libblkid debug output.

LOCK_BLOCK_DEVICE=<mode>

use exclusive BSD lock. The mode is "1" or "0". See --lock for more details.

## NOTES
The maximum useful size of a swap area depends on the architecture and the kernel version.

The maximum number of the pages that is possible to address by swap area header is 4294967295 (32-bit unsigned int). The remaining space on the swap device is ignored.

Presently, Linux allows 32 swap areas. The areas in use can be seen in the file /proc/swaps.

mkswap refuses areas smaller than 10 pages.

If you don’t know the page size that your machine uses, you can look it up with getconf PAGESIZE.

To set up a swap file, it is necessary to create that file before initializing it with mkswap, e.g. using a command like

```
# dd if=/dev/zero of=swapfile bs=1MiB count=$((8*1024))
```

to create 8GiB swapfile.

Please read notes from swapon(8) about the swap file use restrictions (holes, preallocation and copy-on-write issues).

## SEE ALSO
fdisk(8), swapon(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The mkswap command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


nologin

title: nologin(8)

summary: politely refuse a login

text:
# nologin(8)

## NAME
nologin — politely refuse a login

## SYNOPSIS
nologin

## DESCRIPTION
nologin displays a message that an account is not available and exits non-zero. It is intended as a replacement shell field for accounts that have been disabled.

If the file /etc/nologin.txt exists, nologin displays its contents to the user instead of the default message.

## SEE ALSO
login(1)

## HISTORY
The nologin command appeared in 4.4BSD.


title: pivot_root(8)

summary: change the root filesystem

text:
# pivot_root(8)

## NAME
pivot_root - change the root filesystem

## SYNOPSIS
pivot_root new_root put_old

## DESCRIPTION
pivot_root moves the root file system of the current process to the directory put_old and makes new_root the new root file system. Since pivot_root(8) simply calls pivot_root(2), we refer to the man page of the latter for further details.

Note that, depending on the implementation of pivot_root, root and current working directory of the caller may or may not change. The following is a sequence for invoking pivot_root that works in either case, assuming that pivot_root and chroot are in the current PATH:

```
cd new_root
pivot_root . put_old
exec chroot . command
```

Note that chroot must be available under the old root and under the new root, because pivot_root may or may not have implicitly changed the root directory of the shell.

Note that exec chroot changes the running executable, which is necessary if the old root directory should be unmounted afterwards. Also note that standard input, output, and error may still point to a device on the old root file system, keeping it busy. They can easily be changed when invoking chroot (see below; note the absence of leading slashes to make it work whether pivot_root has changed the shell’s root or not).

## OPTIONS
-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## EXAMPLE
Change the root file system to /dev/hda1 from an interactive shell:

```
mount /dev/hda1 /new-root
cd /new-root
pivot_root . old-root
exec chroot . sh <dev/console >dev/console 2>&1
umount /old-root
```

Mount the new root file system over NFS from 10.0.0.1:/my_root and run init:

```
ifconfig lo 127.0.0.1 up   # for portmap
# configure Ethernet or such
portmap   # for lockd (implicitly started by mount)
mount -o ro 10.0.0.1:/my_root /mnt
killall portmap   # portmap keeps old root busy
cd /mnt
pivot_root . old_root
exec chroot . sh -c 'umount /old_root; exec /sbin/init' \

  <dev/console >dev/console 2>&1
```

## SEE ALSO
chroot(1), pivot_root(2), mount(8), switch_root(8), umount(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The pivot_root command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


readprofile

title: readprofile(8)

summary: read kernel profiling information

text:
# readprofile(8)

## NAME
readprofile - read kernel profiling information

## SYNOPSIS
readprofile [options]

## VERSION
This manpage documents version 2.0 of the program.

## DESCRIPTION
The readprofile command uses the /proc/profile information to print ascii data on standard output. The output is organized in three columns: the first is the number of clock ticks, the second is the name of the C function in the kernel where those many ticks occurred, and the third is the normalized `load' of the procedure, calculated as a ratio between the number of ticks and the length of the procedure. The output is filled with blanks to ease readability.

## OPTIONS
-a, --all

Print all symbols in the mapfile. By default the procedures with reported ticks are not printed.

-b, --histbin

Print individual histogram-bin counts.

-i, --info

Info. This makes readprofile only print the profiling step used by the kernel. The profiling step is the resolution of the profiling buffer, and is chosen during kernel configuration (through make config), or in the kernel’s command line. If the -t (terse) switch is used together with -i only the decimal number is printed.

-m, --mapfile mapfile

Specify a mapfile, which by default is /usr/src/linux/System.map. You should specify the map file on cmdline if your current kernel isn’t the last one you compiled, or if you keep System.map elsewhere. If the name of the map file ends with .gz it is decompressed on the fly.

-M, --multiplier multiplier

On some architectures it is possible to alter the frequency at which the kernel delivers profiling interrupts to each CPU. This option allows you to set the frequency, as a multiplier of the system clock frequency, HZ. Linux 2.6.16 dropped multiplier support for most systems. This option also resets the profiling buffer, and requires superuser privileges.

-p, --profile pro-file

Specify a different profiling buffer, which by default is /proc/profile. Using a different pro-file is useful if you want to `freeze' the kernel profiling at some time and read it later. The /proc/profile file can be copied using cat(1) or cp(1). There is no more support for compressed profile buffers, like in readprofile-1.1, because the program needs to know the size of the buffer in advance.

-r, --reset

Reset the profiling buffer. This can only be invoked by root, because /proc/profile is readable by everybody but writable only by the superuser. However, you can make readprofile set-user-ID 0, in order to reset the buffer without gaining privileges.

-s, --counters

Print individual counters within functions.

-v, --verbose

Verbose. The output is organized in four columns and filled with blanks. The first column is the RAM address of a kernel function, the second is the name of the function, the third is the number of clock ticks and the last is the normalized load.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## FILES
/proc/profile

A binary snapshot of the profiling buffer.

/usr/src/linux/System.map

The symbol table for the kernel.

/usr/src/linux/*

The program being profiled :-)

## BUGS
readprofile only works with a 1.3.x or newer kernel, because /proc/profile changed in the step from 1.2 to 1.3.

This program only works with ELF kernels. The change for a.out kernels is trivial, and left as an exercise to the a.out user.

To enable profiling, the kernel must be rebooted, because no profiling module is available, and it wouldn’t be easy to build. To enable profiling, you can specify profile=2 (or another number) on the kernel commandline. The number you specify is the two-exponent used as profiling step.

Profiling is disabled when interrupts are inhibited. This means that many profiling ticks happen when interrupts are re-enabled. Watch out for misleading information.

## EXAMPLE
Browse the profiling buffer ordering by clock ticks:

```
   readprofile | sort -nr | less
```

Print the 20 most loaded procedures:

```
   readprofile | sort -nr +2 | head -20
```

Print only filesystem profile:

```
   readprofile | grep _ext2
```

Look at all the kernel information, with ram addresses:

```
   readprofile -av | less
```

Browse a 'frozen' profile buffer for a non current kernel:

```
   readprofile -p ~/profile.freeze -m /zImage.map.gz
```

Request profiling at 2kHz per CPU, and reset the profiling buffer:

```
   sudo readprofile -M 20
```

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The readprofile command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


rtcwake

title: rtcwake(8)

text:
# rtcwake(8)

## NAME
rtcwake - enter a system sleep state until specified wakeup time

## SYNOPSIS
rtcwake [options] [-d device] [-m standby_mode] {-s seconds|-t time_t}

## DESCRIPTION
This program is used to enter a system sleep state and to automatically wake from it at a specified time.

This uses cross-platform Linux interfaces to enter a system sleep state, and leave it no later than a specified time. It uses any RTC framework driver that supports standard driver model wakeup flags.

This is normally used like the old apmsleep utility, to wake from a suspend state like ACPI S1 (standby) or S3 (suspend-to-RAM). Most platforms can implement those without analogues of BIOS, APM, or ACPI.

On some systems, this can also be used like nvram-wakeup, waking from states like ACPI S4 (suspend to disk). Not all systems have persistent media that are appropriate for such suspend modes.

Note that alarm functionality depends on hardware; not every RTC is able to setup an alarm up to 24 hours in the future.

The suspend setup may be interrupted by active hardware; for example wireless USB input devices that continue to send events for some fraction of a second after the return key is pressed. rtcwake tries to avoid this problem and it waits to the terminal to settle down before entering a system sleep.

## OPTIONS
-A, --adjfile file

Specify an alternative path to the adjust file.

-a, --auto

Read the clock mode (whether the hardware clock is set to UTC or local time) from the adjtime file, where hwclock(8) stores that information. This is the default.

--date timestamp

Set the wakeup time to the value of the timestamp. Format of the timestamp can be any of the following:

YYYYMMDDhhmmss

YYYY-MM-DD hh:mm:ss

YYYY-MM-DD hh:mm

(seconds will be set to 00)

YYYY-MM-DD

(time will be set to 00:00:00)

hh:mm:ss

(date will be set to today)

hh:mm

(date will be set to today, seconds to 00)

tomorrow

(time is set to 00:00:00)

+5min

-d, --device device

Use the specified device instead of rtc0 as realtime clock. This option is only relevant if your system has more than one RTC. You may specify rtc1, rtc2, ... here.

-l, --local

Assume that the hardware clock is set to local time, regardless of the contents of the adjtime file.

--list-modes

List available --mode option arguments.

-m, --mode mode

Go into the given standby state. Valid values for mode are: standby

ACPI state S1. This state offers minimal, though real, power savings, while providing a very low-latency transition back to a working system. This is the default mode.

freeze

The processes are frozen, all the devices are suspended and all the processors idled. This state is a general state that does not need any platform-specific support, but it saves less power than Suspend-to-RAM, because the system is still in a running state. (Available since Linux 3.9.)

mem

ACPI state S3 (Suspend-to-RAM). This state offers significant power savings as everything in the system is put into a low-power state, except for memory, which is placed in self-refresh mode to retain its contents.

disk

ACPI state S4 (Suspend-to-disk). This state offers the greatest power savings, and can be used even in the absence of low-level platform support for power management. This state operates similarly to Suspend-to-RAM, but includes a final step of writing memory contents to disk.

off

ACPI state S5 (Poweroff). This is done by calling '/sbin/shutdown'. Not officially supported by ACPI, but it usually works.

no

Don’t suspend, only set the RTC wakeup time.

on

Don’t suspend, but read the RTC device until an alarm time appears. This mode is useful for debugging.

disable

Disable a previously set alarm.

show

Print alarm information in format: "alarm: off|on <time>". The time is in ctime() output format, e.g., "alarm: on Tue Nov 16 04:48:45 2010".

-n, --dry-run

This option does everything apart from actually setting up the alarm, suspending the system, or waiting for the alarm.

-s, --seconds seconds

Set the wakeup time to seconds in the future from now.

-t, --time time_t

Set the wakeup time to the absolute time time_t. time_t is the time in seconds since 1970-01-01, 00:00 UTC. Use the date(1) tool to convert between human-readable time and time_t.

-u, --utc

Assume that the hardware clock is set to UTC (Universal Time Coordinated), regardless of the contents of the adjtime file.

-v, --verbose

Be verbose.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## NOTES
Some PC systems can’t currently exit sleep states such as mem using only the kernel code accessed by this driver. They need help from userspace code to make the framebuffer work again.

## FILES
/etc/adjtime

## HISTORY
The program was posted several times on LKML and other lists before appearing in kernel commit message for Linux 2.6 in the GIT commit 87ac84f42a7a580d0dd72ae31d6a5eb4bfe04c6d.

## AUTHORS
The program was written by David Brownell <dbrownell@users.sourceforge.net> and improved by Bernhard Walle <bwalle@suse.de>.

## COPYRIGHT
This is free software. You may redistribute copies of it under the terms of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. There is NO WARRANTY, to the extent permitted by law.

## SEE ALSO
adjtime_config(5), hwclock(8), date(1)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The rtcwake command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


swaplabel

title: swaplabel(8)

text:
# swaplabel(8)

## NAME
swaplabel - print or change the label or UUID of a swap area

## SYNOPSIS
swaplabel [-L label] [-U UUID] device

## DESCRIPTION
swaplabel will display or change the label or UUID of a swap partition located on device (or regular file).

If the optional arguments -L and -U are not given, swaplabel will simply display the current swap-area label and UUID of device.

If an optional argument is present, then swaplabel will change the appropriate value on device. These values can also be set during swap creation using mkswap(8). The swaplabel utility allows changing the label or UUID on an actively used swap device.

## OPTIONS
-h, --help

Display help text and exit.

-V, --version

Print version and exit.

-L, --label label

Specify a new label for the device. Swap partition labels can be at most 16 characters long. If label is longer than 16 characters, swaplabel will truncate it and print a warning message.

-U, --uuid UUID

Specify a new UUID for the device. The UUID must be in the standard 8-4-4-4-12 character format, such as is output by uuidgen(1).

## ENVIRONMENT
LIBBLKID_DEBUG=all

enables libblkid debug output.

## AUTHORS
swaplabel was written by Jason Borden <jborden@bluehost.com> and Karel Zak <kzak@redhat.com>.

## SEE ALSO
uuidgen(1), mkswap(8), swapon(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The swaplabel command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


title: switch_root(8)

text:
# switch_root(8)

## NAME
switch_root - switch to another filesystem as the root of the mount tree

## SYNOPSIS
switch_root [-hV]

switch_root newroot init [arg...]

## DESCRIPTION
switch_root moves already mounted /proc, /dev, /sys and /run to newroot and makes newroot the new root filesystem and starts init process.

WARNING: switch_root removes recursively all files and directories on the current root filesystem.

## OPTIONS
-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## EXIT STATUS
switch_root returns 1 on failure, it never returns on success.

## NOTES
switch_root will fail to function if newroot is not the root of a mount. If you want to switch root into a directory that does not meet this requirement then you can first use a bind-mounting trick to turn any directory into a mount point:

```
mount --bind $DIR $DIR
```

## AUTHORS
Peter Jones <pjones@redhat.com>, Jeremy Katz <katzj@redhat.com>, Karel Zak <kzak@redhat.com>

## SEE ALSO
chroot(2), init(8), mkinitrd(8), mount(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The switch_root command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


wdctl

title: wdctl(8)

summary: show hardware watchdog status

text:
# wdctl(8)

## NAME
wdctl - show hardware watchdog status

## SYNOPSIS
wdctl [options] [device...]

## DESCRIPTION
Show hardware watchdog status. The default device is /dev/watchdog. If more than one device is specified then the output is separated by one blank line.

If the device is already used or user has no permissions to read from the device, then wdctl reads data from sysfs. In this case information about supported features (flags) might be missing.

Note that the number of supported watchdog features is hardware specific.

## OPTIONS
-f, --flags list

Print only the specified flags.

-F, --noflags

Do not print information about flags.

-I, --noident

Do not print watchdog identity information.

-n, --noheadings

Do not print a header line for flags table.

-o, --output list

Define the output columns to use in table of watchdog flags. If no output arrangement is specified, then a default set is used. Use --help to get list of all supported columns.

-O, --oneline

Print all wanted information on one line in key="value" output format.

-p, --setpretimeout seconds

Set the watchdog pre-timeout in seconds. A watchdog pre-timeout is a notification generated by the watchdog before the watchdog reset might occur in the event the watchdog has not been serviced. This notification is handled by the kernel and can be configured to take an action using sysfs or by --setpregovernor.

-g, --setpregovernor governor

Set pre-timeout governor name. For available governors see default wdctl output.

-r, --raw

Use the raw output format.

-s, --settimeout seconds

Set the watchdog timeout in seconds.

-T, --notimeouts

Do not print watchdog timeouts.

-x, --flags-only

Same as -I -T.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## AUTHORS
Karel Zak <kzak@redhat.com>, Lennart Poettering <lennart@poettering.net>

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The wdctl command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


wipefs

title: wipefs(8)

summary: wipe a signature from a device

text:
# wipefs(8)

## NAME
wipefs - wipe a signature from a device

## SYNOPSIS
wipefs [options] device...

wipefs [--backup] -o offset device...

wipefs [--backup] -a device...

## DESCRIPTION
wipefs can erase filesystem, raid or partition-table signatures (magic strings) from the specified device to make the signatures invisible for libblkid. wipefs does not erase the filesystem itself nor any other data from the device.

When used without any options, wipefs lists all visible filesystems and the offsets of their basic signatures. The default output is subject to change. So whenever possible, you should avoid using default outputs in your scripts. Always explicitly define expected columns by using --output columns-list in environments where a stable output is required.

wipefs calls the BLKRRPART ioctl when it has erased a partition-table signature to inform the kernel about the change. The ioctl is called as the last step and when all specified signatures from all specified devices are already erased. This feature can be used to wipe content on partitions devices as well as partition table on a disk device, for example by wipefs -a /dev/sdc1 /dev/sdc2 /dev/sdc.

Note that some filesystems and some partition tables store more magic strings on the device (e.g., FAT, ZFS, GPT). The wipefs command (since v2.31) lists all the offset where a magic strings have been detected.

When option -a is used, all magic strings that are visible for libblkid(3) are erased. In this case the wipefs scans the device again after each modification (erase) until no magic string is found.

Note that by default wipefs does not erase nested partition tables on non-whole disk devices. For this the option --force is required.

## OPTIONS
-a, --all

Erase all available signatures. The set of erased signatures can be restricted with the -t option.

-b, --backup

Create a signature backup to the file $HOME/wipefs-<devname>-<offset>.bak. For more details see the EXAMPLE section.

-f, --force

Force erasure, even if the filesystem is mounted. This is required in order to erase a partition-table signature on a block device.

-J, --json

Use JSON output format.

--lock[=mode]

Use exclusive BSD lock for device or file it operates. The optional argument mode can be yes, no (or 1 and 0) or nonblock. If the mode argument is omitted, it defaults to "yes". This option overwrites environment variable $LOCK_BLOCK_DEVICE. The default is not to use any lock at all, but it’s recommended to avoid collisions with udevd or other tools.

-i, --noheadings

Do not print a header line.

-O, --output list

Specify which output columns to print. Use --help to get a list of all supported columns.

-n, --no-act

Causes everything to be done except for the write(2) call.

-o, --offset offset

Specify the location (in bytes) of the signature which should be erased from the device. The offset number may include a "0x" prefix; then the number will be interpreted as a hex value. It is possible to specify multiple -o options. The offset argument may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB"), or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.

-p, --parsable

Print out in parsable instead of printable format. Encode all potentially unsafe characters of a string to the corresponding hex value prefixed by '\x'.

-q, --quiet

Suppress any messages after a successful signature wipe.

-t, --types list

Limit the set of printed or erased signatures. More than one type may be specified in a comma-separated list. The list or individual types can be prefixed with 'no' to specify the types on which no action should be taken. For more details see mount(8).

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## ENVIRONMENT
LIBBLKID_DEBUG=all

enables libblkid(3) debug output.

LOCK_BLOCK_DEVICE=<mode>

use exclusive BSD lock. The mode is "1" or "0". See --lock for more details.

## EXAMPLES
wipefs /dev/sda*

Prints information about sda and all partitions on sda.

wipefs --all --backup /dev/sdb

Erases all signatures from the device /dev/sdb and creates a signature backup file ~/wipefs-sdb-<offset>.bak for each signature.

dd if=~/wipefs-sdb-0x00000438.bak of=/dev/sdb seek=$((0x00000438)) bs=1 conv=notrunc

Restores an ext2 signature from the backup file ~/wipefs-sdb-0x00000438.bak.

## AUTHORS
Karel Zak <kzak@redhat.com>

## SEE ALSO
blkid(8), findfs(8)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The wipefs command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


zramctl

title: zramctl(8)

summary: set up and control zram devices

text:
# zramctl(8)

## NAME
zramctl - set up and control zram devices

## SYNOPSIS
Get info:

zramctl [options]

Reset zram:

zramctl -r zramdev...

Print name of first unused zram device:

zramctl -f

Set up a zram device:

zramctl [-f | zramdev] [-s size] [-t number] [-a algorithm]

## DESCRIPTION
zramctl is used to quickly set up zram device parameters, to reset zram devices, and to query the status of used zram devices.

If no option is given, all non-zero size zram devices are shown.

Note that zramdev node specified on command line has to already exist. The command zramctl creates a new /dev/zram<N> nodes only when --find option specified. It’s possible (and common) that after system boot /dev/zram<N> nodes are not created yet.

## OPTIONS
-a, --algorithm lzo|lz4|lz4hc|deflate|842|zstd

Set the compression algorithm to be used for compressing data in the zram device. The list of supported algorithms could be inaccurate as it depends on the current kernel configuration. A basic overview can be obtained by using the command "cat /sys/block/zram0/comp_algorithm"; however, please note that this list might also be incomplete. This is due to the fact that ZRAM utilizes the Crypto API, and if certain algorithms were built as modules, it becomes impossible to enumerate all of them.

-f, --find

Find the first unused zram device. If a --size argument is present, then initialize the device.

-n, --noheadings

Do not print a header line in status output.

-o, --output list

Define the status output columns to be used. If no output arrangement is specified, then a default set is used. Use --help to get a list of all supported columns.

--output-all

Output all available columns.

--raw

Use the raw format for status output.

-r, --reset

Reset the options of the specified zram device(s). Zram device settings can be changed only after a reset.

-s, --size size

Create a zram device of the specified size. Zram devices are aligned to memory pages; when the requested size is not a multiple of the page size, it will be rounded up to the next multiple. When not otherwise specified, the unit of the size parameter is bytes. The size argument may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.

-t, --streams number

Set the maximum number of compression streams that can be used for the device. The default is use all CPUs and one stream for kernels older than 4.6.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## EXIT STATUS
zramctl returns 0 on success, nonzero on failure.

## FILES
/dev/zram[0..N]

zram block devices

## EXAMPLE
The following commands set up a zram device with a size of one gigabyte and use it as swap device.

```
 # zramctl --find --size 1024M

 /dev/zram0

 # mkswap /dev/zram0

 # swapon /dev/zram0

 ...

 # swapoff /dev/zram0

 # zramctl --reset /dev/zram0
```

## AUTHORS
Timofey Titovets <nefelim4ag@gmail.com>, Karel Zak <kzak@redhat.com>

## SEE ALSO
Linux kernel documentation <https://docs.kernel.org/admin-guide/blockdev/zram.html>

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The zramctl command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


uucico

package: uucp

title: uucico(8)

summary: UUCP file transfer daemon

text:
# uucico(8)

## NAME
uucico - UUCP file transfer daemon

## SYNOPSIS
uucico [ options ]

## DESCRIPTION
The uucico daemon processes file transfer requests queued by uucp (1) and uux (1). It is started when uucp or uux is run (unless they are given the -r option). It is also typically started periodically using entries in the crontab table(s).

When invoked with -r1, --master, -s, --system, or -S, the daemon will place a call to a remote system, running in master mode. Otherwise the daemon will start in slave mode, accepting a call from a remote system. Typically a special login name will be set up for UUCP which automatically invokes uucico when a call is made.

When uucico terminates, it invokes the uuxqt (8) daemon, unless the -q or --nouuxqt option is given; uuxqt (8) executes any work orders created by uux (1) on a remote system, and any work orders created locally which have received remote files for which they were waiting.

If a call fails, uucico will normally refuse to retry the call until a certain (configurable) amount of time has passed. This may be overriden by the -f, --force, or -S option.

The -l, --prompt, -e, or --loop options may be used to force uucico to produce its own prompts of "login: " and "Password:". When another daemon calls in, it will see these prompts and log in as usual. The login name and password will normally be checked against a separate list kept specially for uucico rather than the /etc/passwd file; it is possible on some systems to direct uucico to use the /etc/passwd file. The -l or --prompt option will prompt once and then exit; in this mode the UUCP administrator or the superuser may use the -u or --login option to force a login name, in which case uucico will not prompt for one. The -e or --loop option will prompt again after the first session is over; in this mode uucico will permanently control a port.

If uucico receives a SIGQUIT, SIGTERM or SIGPIPE signal, it will cleanly abort any current conversation with a remote system and exit. If it receives a SIGHUP signal it will abort any current conversation, but will continue to place calls to (if invoked with -r1 or --master) and accept calls from (if invoked with -e or --loop) other systems. If it receives a SIGINT signal it will finish the current conversation, but will not place or accept any more calls.

## OPTIONS
The following options may be given to uucico.

-r1, --master

Start in master mode (call out to a system); implied by -s, --system, or -S. If no system is specified, call any system for which work is waiting to be done.

-r0, --slave

Start in slave mode. This is the default.

-s system, --system system

Call the named system.

-S system

Call the named system, ignoring any required wait. This is equivalent to -s system -f.

-f, --force

Ignore any required wait for any systems to be called.

-l, --prompt

Prompt for login name and password using "login: " and "Password:". This allows uucico to be easily run from inetd (8). The login name and password are checked against the UUCP password file, which probably has no connection to the file /etc/passwd. The --login option may be used to force a login name, in which cause uucico will only prompt for a password.

-p port, --port port

Specify a port to call out on or to listen to.

-e, --loop

Enter endless loop of login/password prompts and slave mode daemon execution. The program will not stop by itself; you must use kill (1) to shut it down.

-w, --wait

After calling out (to a particular system when -s, --system, or -S is specifed, or to all systems which have work when just -r1 or --master is specifed), begin an endless loop as with --loop.

-q, --nouuxqt

Do not start the uuxqt (8) daemon when finished.

-c, --quiet

If no calls are permitted at this time, then don't make the call, but also do not put an error message in the log file and do not update the system status (as reported by uustat (1)). This can be convenient for automated polling scripts, which may want to simply attempt to call every system rather than worry about which particular systems may be called at the moment. This option also suppresses the log message indicating that there is no work to be done.

-C, --ifwork

Only call the system named by -s, --system or -S if there is work for that system.

-D, --nodetach

Do not detach from the controlling terminal. Normally uucico detaches from the terminal before each call out to another system and before invoking uuxqt. This option prevents this.

-u name, --login name

Set the login name to use instead of that of the invoking user. This option may only be used by the UUCP administrator or the superuser. If used with --prompt, this will cause uucico to prompt only for the password, not the login name.

-z, --try-next

If a call fails after the remote system is reached, try the next alternate rather than simply exiting.

-i type, --stdin type

Set the type of port to use when using standard input. The only support port type is TLI, and this is only available on machines which support the TLI networking interface. Specifying -iTLI causes uucico to use TLI calls to perform I/O.

-x type, -X type, --debug type

Turn on particular debugging types. The following types are recognized: abnormal, chat, handshake, uucp-proto, proto, port, config, spooldir, execute, incoming, outgoing. Multiple types may be given, separated by commas, and the --debug option may appear multiple times. A number may also be given, which will turn on that many types from the foregoing list; for example, --debug 2 is equivalent to --debug abnormal,chat.

The debugging output is sent to the debugging file, which may be printed using uulog -D.

-I file, --config file

Set configuration file to use. This option may not be available, depending upon how uucico was compiled.

-v, --version

Report version information and exit.

--help

Print a help message and exit.

## SEE ALSO
kill(1), uucp(1), uux(1), uustat(1), uuxqt(8)

## AUTHOR
Ian Lance Taylor <ian@airs.com>


uuxqt

title: uuxqt(8)

summary: UUCP execution daemon

text:
# uuxqt(8)

## NAME
uuxqt - UUCP execution daemon

## SYNOPSIS
uuxqt [ options ]

## DESCRIPTION
The uuxqt daemon executes commands requested by uux (1) from either the local system or from remote systems. It is started automatically by the uucico (8) daemon (unless uucico (8) is given the -q or --nouuxqt option).

There is normally no need to run this command, since it will be invoked by uucico (8). However, it can be used to provide greater control over the processing of the work queue.

Multiple invocations of uuxqt may be run at once, as controlled by the max-uuxqts configuration command.

## OPTIONS
The following options may be given to uuxqt.

-c command, --command command

Only execute requests for the specified command. For example:

```
uuxqt --command rmail
```

-s system, --system system

Only execute requests originating from the specified system.

-x type, --debug type

Turn on particular debugging types. The following types are recognized: abnormal, chat, handshake, uucp-proto, proto, port, config, spooldir, execute, incoming, outgoing. Only abnormal, config, spooldir and execute are meaningful for uuxqt. Multiple types may be given, separated by commas, and the --debug option may appear multiple times. A number may also be given, which will turn on that many types from the foregoing list; for example, --debug 2 is equivalent to --debug abnormal,chat.

The debugging output is sent to the debugging file, which may be printed using uulog -D.

-I file, --config

Set configuration file to use. This option may not be available, depending upon how uuxqt was compiled.

-v, --version

Report version information and exit.

--help

Print a help message and exit.

## SEE ALSO
uucp(1), uux(1), uucico(8)

## AUTHOR
Ian Lance Taylor (ian@airs.com)


uuidd

package: uuidd

title: uuidd(8)

summary: UUID generation daemon

text:
# uuidd(8)

## NAME
uuidd - UUID generation daemon

## SYNOPSIS
uuidd [options]

## DESCRIPTION
The uuidd daemon is used by the UUID library to generate universally unique identifiers (UUIDs), especially time-based UUIDs, in a secure and guaranteed-unique fashion, even in the face of large numbers of threads running on different CPUs trying to grab UUIDs.

## OPTIONS
-C, --cont-clock[=time]

Activate continuous clock handling for time based UUIDs. uuidd could use all possible clock values, beginning with the daemon’s start time. The optional argument can be used to set a value for the max_clock_offset. This gurantees, that a clock value of a UUID will always be within the range of the max_clock_offset. The option '-C' or '--cont-clock' enables the feature with a default max_clock_offset of 2 hours.

The option '-C<NUM>[hd]' or '--cont-clock=<NUM>[hd]' enables the feature with a max_clock_offset of NUM seconds. In case of an appended h or d, the NUM value is read in hours or days. The minimum value is 60 seconds, the maximum value is 365 days.

-d, --debug

Run uuidd in debugging mode. This prevents uuidd from running as a daemon.

-F, --no-fork

Do not daemonize using a double-fork.

-k, --kill

If currently a uuidd daemon is running, kill it.

-n, --uuids number

When issuing a test request to a running uuidd, request a bulk response of number UUIDs.

-P, --no-pid

Do not create a pid file.

-p, --pid path

Specify the pathname where the pid file should be written. By default, the pid file is written to {runstatedir}/uuidd/uuidd.pid.

-q, --quiet

Suppress some failure messages.

-r, --random

Test uuidd by trying to connect to a running uuidd daemon and request it to return a random-based UUID.

-S, --socket-activation

Do not create a socket but instead expect it to be provided by the calling process. This implies --no-fork and --no-pid. This option is intended to be used only with systemd(1). It needs to be enabled with a configure option.

-s, --socket path

Make uuidd use this pathname for the unix-domain socket. By default, the pathname used is {runstatedir}/uuidd/request. This option is primarily for debugging purposes, since the pathname is hard-coded in the libuuid library.

-T, --timeout number

Make uuidd exit after number seconds of inactivity.

-t, --time

Test uuidd by trying to connect to a running uuidd daemon and request it to return a time-based UUID.

-h, --help

Display help text and exit.

-V, --version

Print version and exit.

## EXAMPLE
Start up a daemon, print 42 random keys, and then stop the daemon:

```
uuidd -p /tmp/uuidd.pid -s /tmp/uuidd.socket
uuidd -d -r -n 42 -s /tmp/uuidd.socket
uuidd -d -k -s /tmp/uuidd.socket
```

## AUTHOR
The uuidd daemon was written by Theodore Ts’o <tytso@mit.edu>.

## SEE ALSO
uuid(3), uuidgen(1)

## REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.

## AVAILABILITY
The uuidd command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.


imapd

package: uw-imap

title: imapd(8)

summary: Internet Message Access Protocol server

text:
# imapd(8)

## NAME
IMAPd - Internet Message Access Protocol server

## SYNOPSIS
/usr/sbin/imapd

## DESCRIPTION
imapd is a server which supports the IMAP4rev1 remote mail access protocol as documented in RFC-3501. imapd is invoked by the internet server (see inetd(8)), normally for requests to connect to the IMAP port as indicated by the /etc/services file (see services(5)). Normally, this is port 143 for plaintext IMAP and 993 for SSL IMAP.

This daemons contains CRAM-MD5 support. See the md5.txt documentation file for additional information.

imapd can also be accessed via rsh(1) by many Unix-based clients. To do this, the imapd binary must have a link to /usr/sbin/rimapd since this is where this software expects it to be located.

## SEE ALSO
rsh(1) ipopd(8)


ipopd

title: ipopd(8)

summary: Post Office Protocol server

text:
# ipopd(8)

## NAME
IPOPd - Post Office Protocol server

## SYNOPSIS
/usr/sbin/ipop2d

/usr/sbin/ipop3d

## DESCRIPTION
ipop2d and ipop3d are servers which support the POP2 and POP3 remote mail access protocols respectively. ipop2d and ipop3d can also be used by POP2 and POP3 clients respecitively to access mailboxes on IMAP servers by specifying a login user name in the form <host>:<user> e.g., SERVER.WASHINGTON.EDU:SMITH.

These daemons contain CRAM-MD5 and APOP support. See the md5.txt documentation file for additional information.

ipop2d and ipop3d are invoked by the internet server (see inetd(8)), normally for requests to connect to the POP port as indicated by the /etc/services file (see services(5)).

## SEE ALSO
imapd(8)

## BUGS
The POP2 and POP3 protocols are intrinsically less flexible than IMAP and do not maintain `read' vs `unread' state on the server. As a result, most POP based software transfers all the mail from the server to the client and deletes it from the server. This necessarily locks the user into using only a single client.

POP3 does not allow you to specify an alternate folder from the user's default.


vblade

package: vblade

title: vblade(8)

summary: export data via ATA over Ethernet

text:
# vblade(8)

## NAME
vblade, vbladed - export data via ATA over Ethernet

## SYNOPSIS

```
vblade [ -m mac[,mac...] ] shelf slot netif filename
```

## DESCRIPTION
The vblade command starts a process that uses raw sockets to perform ATA over Ethernet, acting like a virtual EtherDrive (R) blade.

The vbladed script can be used to daemonize the vblade process, detaching it from your terminal and sending its output to the system logs.

### Arguments
shelf

This should be the shelf address (major AoE address) of the AoE device to create.

slot

This should be the slot address (minor AoE address) of the AoE device to create.

netif

The name of the ethernet network interface to use for AoE communications.

filename

The name of the regular file or block device to export.

### Options
-b

The -b flag takes an argument, the advertised buffer count, specifying the maximum number of outstanding messages the server can queue for processing.

-d

The -d flag selects O_DIRECT mode for accessing the underlying block device.

-s

The -s flag selects O_SYNC mode for accessing the underlying block device, so all writes are committed to disk before returning to the client.

-r

The -r flag restricts the export of the device to be read-only.

-m

The -m flag takes an argument, a comma separated list of MAC addresses permitted access to the vblade. A MAC address can be specified in upper or lower case, with or without colons.

-o

The -o flag takes an argument, the number of sectors at the beginning of the exported file that are excluded from AoE export (default zero).

-l

The -l flag takes an argument, the number of sectors to export. Defaults to the file size in sectors minus the offset.

## EXAMPLE
In this example, the root user on a host named nai exports a file named "3TB" to the LAN on eth0 using AoE shelf address 11 and slot address 1. The process runs in the foreground. Using vbladed would have resulted in the process running as a daemon in the background.

```
nai:~# vblade 11 1 eth0 /data/3TB
```

## BUGS
Users of Jumbo frames should read the README file distributed with vblade to learn about a workaround for kernel buffering limitations.

## AUTHOR
Brantley Coile (brantley@coraid.com)


cron

package: vixie-cron

title: cron(8)

summary: clock daemon

text:
# cron(8)

## NAME
cron — clock daemon

## SYNOPSIS
cron

[-l load_avg] [-n] [-x [ext,sch,proc,pars,load,misc,test,bit]]

## DESCRIPTION
The cron daemon schedules commands to be run at specified dates and times. Commands that are to be run periodically are specified within crontab(5) files. Commands that are only to be run once are scheduled via the at(1) and batch(1) commands. Normally, the cron daemon is started from the /etc/init.d/crond command script. Because it can execute commands on a user's behalf, cron should be run late in the startup sequence, as close to the time when logins are accepted as possible.

cron loads crontab(5) and at(1) files when it starts up and also when changes are made via the crontab(1) and at(1) commands. Additionally, cron checks the modification time on the system crontab file (/etc/crontab), the crontab spool (/var/spool/cron), and the at spool (/var/spool/at) once a minute. If the modification time has changed, the affected files are reloaded.

Any output produced by a command is sent to the user specified in the MAILTO environment variable as set in the crontab(5) file or, if no MAILTO variable is set (or if this is an at(1) or batch(1) job), to the job's owner. If a command produces no output or if the MAILTO environment variable is set to the empty string, no mail will be sent. The exception to this is at(1) or batch(1) jobs submitted with the -m flag. In this case, mail will be sent even if the job produces no output.

### Daylight Saving Time and other time changes
Local time changes of less than three hours, such as those caused by the start or end of Daylight Saving Time, are handled specially. This only applies to jobs that run at a specific time and jobs that are run with a granularity greater than one hour. Jobs that run more frequently are scheduled normally.

If time has moved forward, those jobs that would have run in the interval that has been skipped will be run immediately. Conversely, if time has moved backward, care is taken to avoid running jobs twice.

Time changes of more than 3 hours are considered to be corrections to the clock or time zone, and the new time is used immediately.

The options are as follows:

-l load_avg

If the current load average is greater than load_avg, batch(1) jobs will not be run. The default value is 1.5. To allow batch(1) jobs to run regardless of the load, a value of 0.0 may be used.

-n

By default, cron will detach from the current tty and become a daemon. The -n option disables this behavior and causes it to run in the foreground.

-x debug_flags

If cron was compiled with debugging support, a number of debugging flags are available to show what cron is doing. The following flags may be specified: ext

show extended information; used in conjunction with other debug flags to provide even more information

sch

print information related to scheduling jobs

proc

print information related to running processes

pars

print information related to parsing crontab(5) files

load

print when loading the databases

misc

show misc other debugging information

test

test mode; don't actually execute commands

Multiple flags may be specified, separated by a comma (‘,’). Regardless of which flags were specified, the -x flag will cause cron to stay in the foreground and not become a daemon.

## SIGNALS
SIGHUP

causes cron to close and reopen its log file. This is useful in scripts which rotate and age log files. On Linux this has no effect because cron logs via syslog(3).

## FILES
/etc/crontab

system crontab file

/etc/cron.d

directory containing system crontab files

/var/spool/at

directory containing at(1) jobs

/var/spool/cron

directory containing individual crontab files

/var/spool/cron/.sock

used by crontab(1) and at(1) to tell cron to check for crontab changes immediately

## SEE ALSO
at(1), crontab(1), syslog(3), crontab(5)

## AUTHORS
Paul Vixie ⟨vixie@isc.org⟩

## CAVEATS
All crontab(5) files must not be readable or writable by any user other than their owner. In practice this means they should be mode 0600. This restriction is enforced automatically by crontab(1).


debugvmfs

package: vmfs-tools

title: debugvmfs(8)

summary: VMFS file system debugger

text:
# debugvmfs(8)

## NAME
debugvmfs - VMFS file system debugger

## SYNOPSIS
debugvmfs VOLUME... COMMAND [ OPTIONS ]

## DESCRIPTION
The debugvmfs program allows to display various informations about VMFS file systems, and to access data within the file systems.

The VOLUME to be opened can be either a block device or an image file. When the VMFS spreads accross several extents, all extents must be given.

Please note that most commands are still likely to change in future versions.

## SPECIFYING FILES
Some commands take a filespec as an argument. A filespec may take either of the following forms:

•A path name, relative to the root of the filesystem if it starts with '/', or relative to the current working directory otherwise (interactive mode only).

•An inode number, enclosed between angle brackets, e.g. '<4>', '<0x1400004>'

## COMMANDS
cat filespec [ ... ]

Outputs the content of the given files from the VMFS.

ls [ -l ] filespec

Lists files contained at the given location within the VMFS. With -l, gives some more information, much like the output from ls(1) when given the -l option.

truncate filespec length

Truncate the file to the specified length. R/W support must be enabled.

chmod filespec mode

Change file permissions to the given mode.

df

Outputs information about file system size.

get_file_block filespec position

Get file block corresponding to position in the specified file.

check_vol_bitmaps

Checks volume bitmaps consistency.

show_heartbeats

Outputs active heartbeats on the file system.

read_block block_id [ ... ]

Outputs content within the specified block_id in binary

get_block_status block_id

Get status (allocated or free) of the specified block_id.

alloc_block_fixed block_id

Allocate the specified block_id. R/W support must be enabled.

alloc_block block_type

Allocate a block of the specified type. R/W support must be enabled. Allowed block types are: 1 (File Block), 2 (Sub-Block), 3 (Pointer Block) and 4 (File Descriptor / Inode).

free_block block_id

Free the specified block_id. R/W support must be enabled. Warning: can cause damage since no heartbeat is used at this time and a block used by a file can be freed.

show

Display value(s) of the given variable. See the VARIABLES section for more details. When no variable is given, it lists the top-level properties.

shell

Starts an interactive session. All of the above commands can be executed from within the interactive session. The current working directory can be changed with the cd command, followed by a filespec.

The following output redirections are supported within the shell:

•cmd > output Puts the output of cmd in the output file.

•cmd >> output Appends the output of cmd to the output file.

•cmd | external command Sends the output of cmd to the input of external command. The external command itself can contain output redirection.

Examples:

•read_block 0x00000681 | less

•cat /.fdc.sf | hexdump -C

•cat /.fdc.sf | hexdump -C > /tmp/fdc.hex

•cat /.fdc.sf | hexdump -C | less

## VARIABLES
Variables in debugvmfs represent structures on the filesystem. The currently supported top-level variables are the following:

•vol_version

•version

•label

•mode

•uuid

•ctime

•block_size

•subblock_size

•fdc_header_size

•fdc_bitmap_count

•fbb

•fdc

•pbc

•sbc

•fs

•lvm

•blkid[blk]

•dirent["path"]

•inode["filespec"]

The vol_version, version, label, mode, uuid, ctime, block_size, subblock_size, fdc_header_size, and fdc_bitmap_count properties are low-level information about the filesystem.

The fbb, fdc, pbc and sbc variables are bitmaps. Running them through the show command will display all the bitmaps header fields. Each of these fields can also be displayed individually:

•bitmap.items_per_bitmap_entry

•bitmap.bmp_entries_per_area

•bitmap.hdr_size

•bitmap.data_size

•bitmap.area_size

•bitmap.area_count

•bitmap.total_items

•bitmap.used_items

•bitmap.free_items

•bitmap.entry[n]

e.g. to display the data size of the fdc bitmap, type show fdc.data_size.

Each bitmap.entry[n] (where 0 ≤ n < bitmap.bmp_entries_per_area * bitmap.area_count) contains information about each entry in the bitmap. The available fields are:

•bitmap.entry[n].id

•bitmap.entry[n].total

•bitmap.entry[n].free

•bitmap.entry[n].ffree

•bitmap.entry[n].mdh

•bitmap.entry[n].item[m]

The bitmap.entry[n].mdh is a metadata header. See further below for more details about metadata headers.

Each bitmap.entry[n].item[m] (where 0 ≤ m < bitmap.items_per_bitmap_entry) contains information about a given item in the given entry. The available fields are:

•bitmap.entry[n].item[m].used

•bitmap.entry[n].item[m].dump

The pbc bitmap has an additional field:

•pbc.entry[n].item[m].blocks

The lvm variable contains low-level information about the physical and logical volumes. The available fields are:

•lvm.uuid

•lvm.size

•lvm.blocks

•lvm.num_extents

•lvm.extent[n]

Each lvm.extent[n] (where 0 ≤ n < lvm.num_extents) contains low-level information about the physical volumes. The available fields are:

•lvm.extent[n].device

•lvm.extent[n].uuid

•lvm.extent[n].lun

•lvm.extent[n].version

•lvm.extent[n].name

•lvm.extent[n].size

•lvm.extent[n].num_segments

•lvm.extent[n].first_segment

•lvm.extent[n].last_segment

Each blkid[blk] (where blk is a block id) contains information on the given block id. The available fields are:

•blkid[blk].item

•blkid[blk].flags

Each dirent[path] (where path is a path relative to the current directory in the shell or / outside the shell) contains information on the directory entry corresponding to the given path. The available fields are:

•dirent["path"].type

•dirent["path"].block_id

•dirent["path"].record_id

•dirent["path"].name

Each inode[filespec] contains information on the inode corresponding to the given filespec. The available fields are:

•inode["filespec"].id

•inode["filespec"].id2

•inode["filespec"].nlink

•inode["filespec"].type

•inode["filespec"].flags

•inode["filespec"].size

•inode["filespec"].blk_size

•inode["filespec"].blk_count

•inode["filespec"].uid

•inode["filespec"].gid

•inode["filespec"].mode

•inode["filespec"].zla

•inode["filespec"].tbz

•inode["filespec"].cow

•inode["filespec"].atime

•inode["filespec"].mtime

•inode["filespec"].ctime

•inode["filespec"].rdm_id

•inode["filespec"].mdh

•inode["filespec"].blocks

Metadata headers are being used in several places, such as bitmap.entry[n].mdh and inode["filespec"].mdh. They mostly contain information about clustered accesses to metadata on the filesystem. The available fields are:

•mdh.magic

•mdh.pos

•mdh.hb_pos

•mdh.hb_lock

•mdh.hb_uuid

•mdh.hb_seq

•mdh.obj_seq

•mdh.mtime

Variable values can also be used in expressions using square brackets to use the variable value as an index. For example:

•blkid[inode["filespec"].id]

Enclosing a variable name with parentheses will use that variable value as a variable name. For example:

•(blkid[blk].item).status

## AUTHORS
Christophe Fillot <cf@utc.fr[1]>, Mike Hommey <mh@glandium.org[2]>

## SEE ALSO
vmfs-fuse(8)

## NOTES
1.

cf@utc.fr

mailto:cf@utc.fr

2.

mh@glandium.org

mailto:mh@glandium.org


fsck.vmfs

title: fsck.vmfs(8)

summary: VMFS file system check utility

text:
# fsck.vmfs(8)

## NAME
fsck.vmfs - VMFS file system check utility

## SYNOPSIS
fsck.vmfs VOLUME...

## DESCRIPTION
The fsck.vmfs performs various integrity checks on a VMFS file system.

The VOLUME to be opened can be either a block device or an image file. When the VMFS spreads accross several extents, all extents must be given.

## AUTHORS
Christophe Fillot <cf@utc.fr[1]>, Mike Hommey <mh@glandium.org[2]>

## SEE ALSO
debugvmfs(8)

## NOTES
1.

cf@utc.fr

mailto:cf@utc.fr

2.

mh@glandium.org

mailto:mh@glandium.org


vmfs-fuse

title: vmfs-fuse(8)

summary: mount VMFS file system

text:
# vmfs-fuse(8)

## NAME
vmfs-fuse - mount VMFS file system

## SYNOPSIS
vmfs-fuse VOLUME... MOUNT_POINT

## DESCRIPTION
The vmfs-fuse program allows to mount VMFS file systems.

The VOLUME to be opened can be either a block device or an image file. When the VMFS spreads accross several extents, all extents must be given.

The MOUNT_POINT indicates where the file system will be attached on the system.

## AUTHORS
Christophe Fillot <cf@utc.fr[1]>, Mike Hommey <mh@glandium.org[2]>

## SEE ALSO
debugvmfs(8)

## NOTES
1.

cf@utc.fr

mailto:cf@utc.fr

2.

mh@glandium.org

mailto:mh@glandium.org


vmfs-lvm

title: vmfs-lvm(8)

summary: VMFS logical volume manager tool

text:
# vmfs-lvm(8)

## NAME
vmfs-lvm - VMFS logical volume manager tool

## SYNOPSIS
vmfs-lvm VOLUME... COMMAND

## DESCRIPTION
The vmfs-lvm program allows handle VMFS physical and logical volumes.

The VOLUME to be opened can be either a block device or an image file. When the VMFS spreads accross several extents, all extents must be given.

## COMMANDS
remove

Removes the last extent of the logical volume. THIS IS EXPERIMENTAL. USE AT YOUR OWN RISK. It is highly recommended that the volume is not mounted at the same time. This means the tool shouldn’t be run on the ESX service console.

## AUTHORS
Christophe Fillot <cf@utc.fr[1]>, Mike Hommey <mh@glandium.org[2]>

## SEE ALSO
vmfs-fuse(8)

## NOTES
1.

cf@utc.fr

mailto:cf@utc.fr

2.

mh@glandium.org

mailto:mh@glandium.org


vmtouch

package: vmtouch

title: vmtouch(8)

summary: the Virtual Memory Toucher

text:
# vmtouch(8)

## NAME
vmtouch - the Virtual Memory Toucher

## SYNOPSIS

```
    vmtouch [OPTIONS] ... FILES OR DIRECTORIES ...
```

## DESCRIPTION
Portable file system cache diagnostics and control.

vmtouch opens every file provided on the command line and maps it into virtual memory with mmap(2). The mappings are opened read-only. It recursively crawls any directories and does the same to all files it finds within them.

With no options, vmtouch will not read from (touch) any memory pages. It will only use mincore(2) to determine how many pages of each file are actually resident in memory. Before exiting, it will print a summary of the total pages encountered and how many were resident.

-t

Touch virtual memory pages. Reads a byte from each page of the file. If the page is not resident in memory, a page fault will be generated and the page will be read from disk into the file system's memory cache. Note: Although each page is guaranteed to have been brought into memory, the page might be evicted from memory by the time the vmtouch command completes.

-e

Evict the mapped pages from the file system cache. They will need to be read in from disk the next time they are accessed. This is the inverse of "-t". Note: Even if the eviction is successful, pages may be paged back into memory by the time the vmtouch command completes.

Note: This option is not portable to all systems. See PORTABILITY below.

-l

Lock pages into physical memory. This option works the same as "-t" except it calls mlock(2) on all the memory mappings and doesn't close the descriptors when finished. At the end of the crawl, if successful, vmtouch will block indefinitely. The files will be locked in physical memory until the vmtouch process is killed. Note: While the vmtouch process is holding memory locks, any processes that access the locked pages will not cause non-resident page faults or address-translation faults although they may still cause TLB misses.

Note: Because vmtouch holds file descriptors open it may reach the "RLIMIT_NOFILE" process file descriptor limit. In this case it will try to increase the descriptor limit which will only work if the process is run with root privileges. Similarly, root privileges are required to exceed the "RLIMIT_MEMLOCK" limit. Even with root privileges, "-l" is limited by both the system file descriptor limit and the system limit on "wired memory".

-L

This option is the same as "-l" except that it uses mlockall(2) at the end of the crawl rather than individually mlock(2)ing each file. Because of this, other unrelated pages belonging to the vmtouch process will also be locked in memory.

-d

Daemon mode. After performing the crawl, disassociate from the terminal and run in the background as a daemon. This option can only be used with the "-l" or "-L" locking modes.

-m <max file size>

Maximum file size to map into virtual memory. Files that are larger than this will be skipped. Examples: 4096, 4k, 100M, 1.5G. The default is 500M.

-p <size range> or <size>

Page mode. Maps the portion of the file specified by a range instead of the entire file. Size format same as for "-m". Omitted range start (end) value means start (end) of file. Single <size> value is equivalent to -<size>, i.e. map the first <size> bytes. Examples: 4k-50k, 100M-2G, -5M, -.

-f

Follow symbolic links. With this option, vmtouch will descend into symbolic links that point to directories and will touch regular files pointed to by symbolic links. Symbolic link loops are detected and issue warnings.

-F

During the crawl, don't recurse into directories that have separate filesystems mounted on them. This is handy to avoid accidentally touching other filesystems that have been mounted underneath your target directory.

-i <pattern>

Can be specified multiple times. Ignores files and directories that match any of the provided patterns. The pattern may include wildcards (remember to escape them from your shell). This option stops the crawl, so can be used to ignore directories and all their contents. Example: vmtouch -i .git -i '*.bak' .

-I <pattern>

Can be specified multiple times. Only processes filenames matching one or more of the provided patterns. The pattern may include wildcards (remember to escape them from your shell). Example: vmtouch -I '*.c' -I '*.h' .

-b <list file>

The list of files/directories to crawl is read from the specified list file, which by default should be a newline-separated list, for example the output from the find command. If the list file is "-" then this list is read from standard input. Example: find /usr/lib -type f | vmtouch -b -

-0

If -b ("batch mode") is in effect, assume the list file is delimited with NUL bytes instead of newlines, for example the output from find -print0. This is useful in case your filenames contain newline characters themselves.

-P <pidfile>

Create a PID file. This option can only be provided in combination with -l or -L. The PID file will be automatically deleted when vmtouch gets a termination signal (SIGINT, SIGTERM, SIGQUIT).

-v

Verbose mode. While crawling, print out every file being processed along with its total number of pages and the number of its pages that are currently resident in memory to standard output.

-q

Quiet mode. Suppress the end of crawl summary and all warnings that are normally printed to standard error. On success print nothing. Fatal errors print a single error message line to standard error.

-h

Normally, if multiple files both point to the same inode then vmtouch will ignore all but the first it finds so as to avoid double-counting their pages. This option overrides this behaviour and double-counts anyways.

## PORTABILITY
The page residency summaries depend on mincore(2) which first appeared in 4.4BSD but is not present on all unix systems.

The "-l" and "-L" locking options depends on mlock(2) or mlockall(2), both of which are specified by POSIX.1b-1993, Real-Time Extensions.

The "-e" page eviction option is the least portable. On Linux it uses posix_fadvise(2) with "POSIX_FADV_DONTNEED" advice to inform the kernel that the file should be evicted from the file system cache. posix_fadvise(2) is specified by POSIX.1-2003 TC1. On FreeBSD, the pages are invalidated with msync(2)'s "MS_INVALIDATE" flag. msync(2) is specified by POSIX.1b-1993, Real-Time Extensions, although this call is not required to remove pages from the file system cache. Some systems like OpenBSD 4.3 don't have posix_fadvise(2), don't evict the pages on an msync(2)/"MS_INVALIDATE", and don't evict the pages with madvise(2)/"MADV_DONTNEED" so "-e" isn't supported on those systems yet. Using "-e" on systems that don't yet support it is a fatal error.

## SUPPORTED SYSTEMS
All vmtouch features have been confirmed to work on the following systems:

Linux 2.6+

FreeBSD 4.X

FreeBSD 7.X

Solaris 10

OS X 10.x

HP-UX 11.31+patches (see below)

Systems that support everything except eviction:

OpenBSD 4.3

CPUs that have been tested:

x86

amd64 (x86-64)

SPARC

ARMv7

We would like to support as many systems as possible so please send us any success reports, failure reports or patches. Thanks!

## SYSTEM NOTES
Shane Seymour did the HP-UX port and says that either 32-bit or 64-bit binaries can be compiled (just use "+DD64" for 64-bit). However, mincore(2) was added to HP-UX 11.31 via patches and at least the following patches need to be installed: PHKL_38651, PHKL_38708, PHKL_38686, PHKL_38688, and PHCO_38658 (or patches that supersede those ones).

## SEE ALSO
Not all the following manual pages may exist in every unix dialect to which vmtouch has been ported.

vmstat(8), touch(1), mmap(2), mincore(2), mlock(2), mlockall(2), msync(2), madvise(2), posix_fadvise(2)

## AUTHOR
Written by Doug Hoyte <doug@hcsw.org>