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busybox

The Swiss Army Knife of Embedded Linux

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examples

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smallest possible linux distribution

Not sure what the "smallest possible" minimum config is, but you can start with an initramfs (see also the kernel documentation) containing just a few files.

That tucks a ramdisk image onto the actual vmlinux kernel before compressing the whole lot, so that on loading it gets automatically retrieved and decompressed. The kernel is started using that memory image as root filesystem, and looks for an executable in there with the name init. Which can be any binary - including busybox.

In fact, using a statically-linked busybox as init inside an initramfs is not an unusual step in embedded device bringup - getting to the shell prompt just past loading the kernel validates that the kernel boots, the kernel/userland interface and the console works.

At this stage, there's no need for any actual storage device, functional root filesystem and all that quite yet. If your device is used in kiosk mode (no data preserved across reboots) it's actually all you need.

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Unmounting Detachable devices (eSATA,USB storage) in Linux

You can use lsof to list open files under a certain directory using lsof +D /path/to/mountpoint.

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Ubuntu system drops to BusyBox prompt while booting, followed by "udevd [94]: timeout: killing '/ sbin / blkid-o udev-p / dev / sda' " error

It looks like the system could not find or mount the partition holding the root filesystem.

The BusyBox prompt is part of the initial RAM disk (initramfs), which is normally used in the early stages of booting Linux, before the root filesystem is loaded. This initramfs, along with the kernel and GRUB (bootloader) data, is typically stored in a separate boot partition. It appears your boot partition is intact.

blkid is responsible for scanning the hard drive and conveying partition information to udev so that it can mount the partitions. Apparently, blkid hung or took too long while scanning for the root partition, so the system killed blkid and the root filesystem could not be mounted. This can be caused by a faulty hard drive or damaged partition data.

There are several things you can do:

  • Make sure that the root partition is correctly specified on the bootloader.
  • Use badblocks to perform a surface scan on the hard drive, using a utility such as Parted Magic, and attempt to repair the root partition if it is damaged.
    • If the hard drive is OK, attempt to recover data from the partition, then delete the partition and reinstall Ubuntu, creating a new partition in its place.
    • If the hard drive has bad blocks, back up all data on the hard drive and replace the drive. The drive is likely to catastrophically fail in this case.

Edit: It appears the hard drive has failed. If the data is valuable, send it to a data recovery service. Replace the hard drive and restore data from backups, if available.

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Search all files containing text

What is the difference between a binary file with the struct

struct MyBin
{
    byte a;
    byte b;
    byte c;
}

with the values

myBin.a = 70;
myBin.b = 111;
myBin.c = 111;

And a text file with the text Foo?

All a text file is, is a binary file that you interpret using special look up codes called Character Encodings (ASCII, UTF-8, ect...). So there is no easy way to tell "Binary Files" apart from "Text Files".

There may be a way to exclude files that have the execute bit set, or only search files under a file-size (I doubt your text file is over 1 MB) but I do not have enough knowledge on how to filter the grep results to give a example of how to do it.

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Stop Linux from allocating more memory to a process

ulimit -v amount_of_memory
./binary

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How can I find out the vfstype of a hard drive partition?

  • With a modern version of mount the file-system type should not need to be specified.
  • sudo blkid displays label, uuid and type (and lsblk to display capacities)
  • file -s /dev/sdX# does the job for partitions as well as disk images.
  • ls /sys/block/*/* is a good resource for many things (but not determining filesystem type)

I assume this is an embedded device, otherwise you should be taking advantage of coreutils, util-linux, etc. rather than busybox.

Let me make this clear, busybox is not consistent across the board - various vendors strip out commands or cripple them to varied degrees. That said, blkid should be available. Run busybox --help which will list the commands compiled into the busybox binary. Also note that often not all those symlinks will exist, so you may need to create them as needed.

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How to display current path in command prompt in linux's sh (not bash)?

Command substitutions in double quotes " get expanded immediately. That is not what you want for your prompt. Single quotes ' will preserve the substitutions in $PS1 which then get only expanded when displaying the prompt. Hence this should work:

export PS1='$(whoami)@$(hostname):$(pwd)'

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How to run a script uninterrupted accross power-cycling

You could add the following to /etc/rc.local:

sudo -u ${USERNAME-TO-RUN-AS} tmux new-session -d -s ${NAME-FOR-SESSION} -d 'sh /path/to/your/script'

Then you can type "tmux attach namefortmuxsession" to view the terminal output from your script.

Replacing /path/to/your/script',$(USERNAME-TO-RUN-AS)and${NAME-FOR-SESSION}` to suit you needs.

Of course, you'll need tmux installed. You could probably do this with screen instead, however I prefer tmux.

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How to make BusyBox running where my backend operating system can be xyz?

"BusyBox is a multi-call binary that combines many common Unix utilities into a single executable."

BusyBox itself cannot be made to "run" as you ask in the title. BusyBox is not a user interface like MythTV or XBMC. Not sure what you mean by install "on top" of an already installed distribution, as the BusyBox executable file can be installed in the filesystem along with all the other utilities. Only when you start replacing the standard utilities with symbolic links to the BusyBox version would you be clobbering the installation.

So that when i telnet i can get something like this following:

If you want to use BusyBox's version of telnet instead of the distro's version of telnet, then you would have to edit the runlevel scripts (or inetd configuration) to use the BusyBox telnet daemon, telnetd, instead of the distro's telnetd.

For a quick experiment, check if any telnet or inet daemons are running in your system by listing all processes:

$ ps -A | grep net

If there is either a telnetd or inetd daemon, then you would have to stop the service or kill the daemon. If there are no telnetd or inetd daemons, then you should be able to manually start the BusyBox telnetd daemon with (might have to preface with sudo):

$ busybox telnetd 

Of course, after you have telnet'd into the PC, the shell would still probably invoke the distro's utilities according to PATH rather than the BusyBox versions. You would have to either install the symbolic links or explicitly use

$ busybox [function] [arguments]...

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How i can install BusyBox on Virtual Machine?

You can't use Busybox alone in a virtual machine.

From the Busybox FAQ:

Busybox is a package that replaces a dozen standard packages, but it is not by itself a complete bootable system.

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How to wait for a response on the inbound side of the socket using NC command under BusyBox?

Are you sure you are not confused about nc? The BusyBox man page states:

nc
nc [OPTIONS] HOST PORT - connect nc [OPTIONS] -l -p PORT [HOST] [PORT] - listen

Options:

    -e PROG         Run PROG after connect (must be last)
    -l              Listen mode, for inbound connects
    -n              Don't do DNS resolution
    -s ADDR         Local address
    -p PORT         Local port
    -u              UDP mode
    -v              Verbose
    -w SEC          Timeout for connects and final net reads
    -i SEC          Delay interval for lines sent
    -o FILE         Hex dump traffic
    -z              Zero-I/O mode (scanning)

so it appears the option to listen on a port is (the traditional) -l, while -w is the timeout for connects and final net reads.

If your problem is to keep listening even after a connection has bene closed, you may use an eternal loop, while true nc -l ....

Edit:

After reading the messages, I realize I did not understand what the OP was asking. The reason why I did not understand is that you cannot use a nc instance for both sending and receiving. You need a separate port, and a separate instance of nc for that. There is no pint in keeping a transmit instance of nc open, if you cannot receive on the same port.

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How to fork two process in inittab without waiting one to finish?

::respawn:-/usr/bin/python /path/to/script.py & /bin/sh -l -c 'chown user1:user1 /tmp/file'

description

BusyBox combines tiny versions of many common UNIX utilities into a single small executable. It provides minimalist replacements for most of the utilities you usually find in GNU coreutils, util-linux, etc. The utilities in BusyBox generally have fewer options than their full-featured GNU cousins; however, the options that are included provide the expected functionality and behave very much like their GNU counterparts.

BusyBox has been written with size-optimization and limited resources in mind. It is also extremely modular so you can easily include or exclude commands (or features) at compile time. This makes it easy to customize your embedded systems. To create a working system, just add /dev, /etc, and a Linux kernel. BusyBox provides a fairly complete POSIX environment for any small or embedded system.

BusyBox is extremely configurable. This allows you to include only the components you need, thereby reducing binary size. Run ’make config’ or ’make menuconfig’ to select the functionality that you wish to enable. Then run ’make’ to compile BusyBox using your configuration.

After the compile has finished, you should use ’make install’ to install BusyBox. This will install the ’bin/busybox’ binary, in the target directory specified by CONFIG_PREFIX . CONFIG_PREFIX can be set when configuring BusyBox, or you can specify an alternative location at install time (i.e., with a command line like ’make CONFIG_PREFIX=/tmp/foo install’). If you enabled any applet installation scheme (either as symlinks or hardlinks), these will also be installed in the location pointed to by CONFIG_PREFIX .

commands

Currently available applets include:

        [, [[, adjtimex, ar, arp, arping, ash, awk, basename, blockdev,
        brctl, bunzip2, bzcat, bzip2, cal, cat, chgrp, chmod, chown, chroot,
        chvt, clear, cmp, cp, cpio, crond, crontab, cttyhack, cut, date, dc,
        dd, deallocvt, depmod, df, diff, dirname, dmesg, dnsdomainname,
        dos2unix, dpkg, dpkg-deb, du, dumpkmap, dumpleases, echo, ed, egrep,
        env, expand, expr, false, fdisk, fgrep, find, fold, free,
        freeramdisk, ftpget, ftpput, getopt, getty, grep, groups, gunzip,
        gzip, halt, head, hexdump, hostid, hostname, httpd, hwclock, id,
        ifconfig, ifdown, ifup, init, insmod, ionice, ip, ipcalc, kill,
        killall, klogd, last, less, ln, loadfont, loadkmap, logger, login,
        logname, logread, losetup, ls, lsmod, lzcat, lzma, md5sum, mdev,
        microcom, mkdir, mkfifo, mknod, mkswap, mktemp, modinfo, modprobe,
        more, mount, mt, mv, nameif, nc, netstat, nslookup, od, openvt,
        passwd, patch, pidof, ping, ping6, pivot_root, poweroff, printf, ps,
        pwd, rdate, readlink, realpath, reboot, renice, reset, rev, rm,
        rmdir, rmmod, route, rpm, rpm2cpio, run-parts, sed, seq,
        setkeycodes, setsid, sh, sha1sum, sha256sum, sha512sum, sleep, sort,
        start-stop-daemon, stat, static-sh, strings, stty, su, sulogin,
        swapoff, swapon, switch_root, sync, sysctl, syslogd, tac, tail, tar,
        taskset, tee, telnet, telnetd, test, tftp, time, timeout, top,
        touch, tr, traceroute, traceroute6, true, tty, tunctl, udhcpc,
        udhcpd, umount, uname, uncompress, unexpand, uniq, unix2dos, unlzma,
        unxz, unzip, uptime, usleep, uudecode, uuencode, vconfig, vi, watch,
        watchdog, wc, wget, which, who, whoami, xargs, xz, xzcat, yes, zcat

command descriptions

adjtimex

adjtimex [-q] [-o OFF ] [-f FREQ ] [-p TCONST ] [-t TICK ]

Read and optionally set system timebase parameters. See adjtimex(2)

        -q      Quiet
        -o OFF  Time offset, microseconds
        -f FREQ Frequency adjust, integer kernel units (65536 is 1ppm)
                (positive values make clock run faster)
        -t TICK Microseconds per tick, usually 10000
        -p TCONST

ar

ar [-o] [-v] [-p] [-t] [-x] ARCHIVE FILES

Extract or list FILES from an ar archive

        -o      Preserve original dates
        -p      Extract to stdout
        -t      List
        -x      Extract
        -v      Verbose

arp

arp [-vn] [-H HWTYPE ] [-i IF ] -a [ HOSTNAME ] [-v] [-i IF ] -d HOSTNAME [pub] [-v] [-H HWTYPE ] [-i IF ] -s HOSTNAME HWADDR [temp] [-v] [-H HWTYPE ] [-i IF ] -s HOSTNAME HWADDR [netmask MASK ] pub [-v] [-H HWTYPE ] [-i IF ] -Ds HOSTNAME IFACE [netmask MASK ] pub

Manipulate ARP cache

        -a              Display (all) hosts
        -s              Set new ARP entry
        -d              Delete a specified entry
        -v              Verbose
        -n              Don't resolve names
        -i IF           Network interface
        -D              Read <hwaddr> from given device
        -A,-p AF        Protocol family
        -H HWTYPE       Hardware address type

arping

arping [-fqbDUA] [-c CNT ] [-w TIMEOUT ] [-I IFACE ] [-s SRC_IP ] DST_IP

Send ARP requests/replies

        -f              Quit on first ARP reply
        -q              Quiet
        -b              Keep broadcasting, don't go unicast
        -D              Duplicated address detection mode
        -U              Unsolicited ARP mode, update your neighbors
        -A              ARP answer mode, update your neighbors
        -c N            Stop after sending N ARP requests
        -w TIMEOUT      Time to wait for ARP reply, seconds
        -I IFACE        Interface to use (default eth0)
        -s SRC_IP       Sender IP address
        DST_IP          Target IP address

ash

ash [-/+OPTIONS] [-/+o OPT ]... [-c ’ SCRIPT ’ [ ARG0 [ ARGS ]] / FILE [ ARGS ]]

Unix shell interpreter

awk

awk [ OPTIONS ] [ AWK_PROGRAM ] [ FILE ]...

        -v VAR=VAL      Set variable
        -F SEP          Use SEP as field separator
        -f FILE         Read program from FILE

basename

basename FILE [ SUFFIX ]

Strip directory path and .SUFFIX from FILE

blockdev

blockdev OPTION BLOCKDEV

        --setro         Set ro
        --setrw         Set rw
        --getro         Get ro
        --getss         Get sector size
        --getbsz        Get block size
        --setbsz BYTES  Set block size
        --getsz         Get device size in 512-byte sectors
        --getsize64     Get device size in bytes
        --flushbufs     Flush buffers
        --rereadpt      Reread partition table

brctl

brctl COMMAND [ BRIDGE [ INTERFACE ]]

Manage ethernet bridges

Commands:

        addbr BRIDGE            Create BRIDGE
        delbr BRIDGE            Delete BRIDGE
        addif BRIDGE IFACE      Add IFACE to BRIDGE
        delif BRIDGE IFACE      Delete IFACE from BRIDGE

bunzip2

bunzip2 [-cf] [ FILE ]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Force

bzcat

bzcat FILE

Decompress to stdout

bzip2

bzip2 [ OPTIONS ] [ FILE ]...

Compress FILEs (or stdin) with bzip2 algorithm

        -1..9   Compression level
        -d      Decompress
        -c      Write to stdout
        -f      Force

cal

cal [-jy] [[ MONTH ] YEAR ]

Display a calendar

        -j      Use julian dates
        -y      Display the entire year

cat

cat [ FILE ]...

Concatenate FILEs and print them to stdout

chgrp

chgrp [-RhLHPcvf]... GROUP FILE ...

Change the group membership of each FILE to GROUP

        -R      Recurse
        -h      Affect symlinks instead of symlink targets
        -L      Traverse all symlinks to directories
        -H      Traverse symlinks on command line only
        -P      Don't traverse symlinks (default)
        -c      List changed files
        -v      Verbose
        -f      Hide errors

chmod

chmod [-Rcvf] MODE[,MODE]... FILE ...

Each MODE is one or more of the letters ugoa, one of the symbols +-= and one or more of the letters rwxst

        -R      Recurse
        -c      List changed files
        -v      List all files
        -f      Hide errors

chown

chown [-RhLHPcvf]... OWNER[<.|:>[ GROUP ]] FILE ...

Change the owner and/or group of each FILE to OWNER and/or GROUP

        -R      Recurse
        -h      Affect symlinks instead of symlink targets
        -L      Traverse all symlinks to directories
        -H      Traverse symlinks on command line only
        -P      Don't traverse symlinks (default)
        -c      List changed files
        -v      List all files
        -f      Hide errors

chroot

chroot NEWROOT [ PROG ARGS ]

Run PROG with root directory set to NEWROOT

chvt

chvt N

Change the foreground virtual terminal to /dev/ttyN

clear

clear

Clear screen

cmp

cmp [-l] [-s] FILE1 [ FILE2 [ SKIP1 [ SKIP2 ]]]

Compare FILE1 with FILE2 (or stdin)

        -l      Write the byte numbers (decimal) and values (octal)
                for all differing bytes
        -s      Quiet

cp

cp [ OPTIONS ] SOURCE ... DEST

Copy SOURCE (s) to DEST

        -a      Same as -dpR
        -R,-r   Recurse
        -d,-P   Preserve symlinks (default if -R)
        -L      Follow all symlinks
        -H      Follow symlinks on command line
        -p      Preserve file attributes if possible
        -f      Overwrite
        -i      Prompt before overwrite
        -l,-s   Create (sym)links

cpio

cpio [-dmvu] [-F FILE ] [-H newc] [-tio] [ EXTR_FILE ]...

Extract or list files from a cpio archive, or create an archive using file list on stdin

Main operation mode:

        -t      List
        -i      Extract EXTR_FILEs (or all)
        -o      Create (requires -H newc)
        -d      Make leading directories
        -m      Preserve mtime
        -v      Verbose
        -u      Overwrite
        -F FILE Input (-t,-i,-p) or output (-o) file
        -H newc Archive format

crond

crond -fbS -l N -L LOGFILE -c DIR

        -f      Foreground
        -b      Background (default)
        -S      Log to syslog (default)
        -l      Set log level. 0 is the most verbose, default 8
        -L      Log to file
        -c      Working dir

crontab

crontab [-c DIR ] [-u USER ] [-ler]|[ FILE ]

        -c      Crontab directory
        -u      User
        -l      List crontab
        -e      Edit crontab
        -r      Delete crontab
        FILE    Replace crontab by FILE ('-': stdin)

cttyhack

cttyhack [ PROG ARGS ]

Give PROG a controlling tty if possible. Example for /etc/inittab (for busybox init): ::respawn:/bin/cttyhack /bin/sh Giving controlling tty to shell running with PID 1: $ exec cttyhack sh Starting interactive shell from boot shell script:

        setsid cttyhack sh

cut

cut [ OPTIONS ] [ FILE ]...

Print selected fields from each input FILE to stdout

        -b LIST Output only bytes from LIST
        -c LIST Output only characters from LIST
        -d CHAR Use CHAR instead of tab as the field delimiter
        -s      Output only the lines containing delimiter
        -f N    Print only these fields
        -n      Ignored

date

date [ OPTIONS ] [+FMT] [ TIME ]

Display time (using +FMT), or set time

        [-s,--set] TIME Set time to TIME
        -u,--utc        Work in UTC (don't convert to local time)
        -R,--rfc-2822   Output RFC-2822 compliant date string
        -I[SPEC]        Output ISO-8601 compliant date string
                        SPEC='date' (default) for date only,
                        'hours', 'minutes', or 'seconds' for date and
                        time to the indicated precision
        -r,--reference FILE     Display last modification time of FILE
        -d,--date TIME  Display TIME, not 'now'
        -D FMT          Use FMT for -d TIME conversion

Recognized TIME formats:

        hh:mm[:ss]
        [YYYY.]MM.DD-hh:mm[:ss]
        YYYY-MM-DD hh:mm[:ss]
        [[[[[YY]YY]MM]DD]hh]mm[.ss]
        'date TIME' form accepts MMDDhhmm[[YY]YY][.ss] instead

dc

dc EXPRESSION ...

Tiny RPN calculator. Operations: +, add, -, sub, *, mul, /, div, %, mod, and, or, not, eor, p - print top of the stack (without popping), f - print entire stack, o - pop the value and set output radix (must be 10, 16, 8 or 2). Examples: ’dc 2 2 add p’ -> 4, ’dc 8 8 * 2 2 + / p’ -> 16

dd

dd [if=FILE] [of=FILE] [ibs=N] [obs=N] [bs=N] [count=N] [skip=N] [seek=N] [conv=notrunc|noerror|sync|fsync]

Copy a file with converting and formatting

        if=FILE         Read from FILE instead of stdin
        of=FILE         Write to FILE instead of stdout
        bs=N            Read and write N bytes at a time
        ibs=N           Read N bytes at a time
        obs=N           Write N bytes at a time
        count=N         Copy only N input blocks
        skip=N          Skip N input blocks
        seek=N          Skip N output blocks
        conv=notrunc    Don't truncate output file
        conv=noerror    Continue after read errors
        conv=sync       Pad blocks with zeros
        conv=fsync      Physically write data out before finishing

Numbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024), MD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824)

deallocvt

deallocvt [N]

Deallocate unused virtual terminal /dev/ttyN

depmod

depmod [-n] [-b BASE ] [ VERSION ] [ MODFILES ]...

Generate modules.dep, alias, and symbols files

        -b BASE Use BASE/lib/modules/VERSION
        -n      Dry run: print files to stdout

df

df [-Pkmhai] [-B SIZE ] [ FILESYSTEM ]...

Print filesystem usage statistics

        -P      POSIX output format
        -k      1024-byte blocks (default)
        -m      1M-byte blocks
        -h      Human readable (e.g. 1K 243M 2G)
        -a      Show all filesystems
        -i      Inodes
        -B SIZE Blocksize

diff

diff [-abBdiNqrTstw] [-L LABEL ] [-S FILE ] [-U LINES ] FILE1 FILE2

Compare files line by line and output the differences between them. This implementation supports unified diffs only.

        -a      Treat all files as text
        -b      Ignore changes in the amount of whitespace
        -B      Ignore changes whose lines are all blank
        -d      Try hard to find a smaller set of changes
        -i      Ignore case differences
        -L      Use LABEL instead of the filename in the unified header
        -N      Treat absent files as empty
        -q      Output only whether files differ
        -r      Recurse
        -S      Start with FILE when comparing directories
        -T      Make tabs line up by prefixing a tab when necessary
        -s      Report when two files are the same
        -t      Expand tabs to spaces in output
        -U      Output LINES lines of context
        -w      Ignore all whitespace

dirname

dirname FILENAME

Strip non-directory suffix from FILENAME

dmesg

dmesg [-c] [-n LEVEL ] [-s SIZE ]

Print or control the kernel ring buffer

        -c              Clear ring buffer after printing
        -n LEVEL        Set console logging level
        -s SIZE         Buffer size

dos2unix

dos2unix [-ud] [ FILE ]

Convert FILE in-place from DOS to Unix format. When no file is given, use stdin/stdout.

        -u      dos2unix
        -d      unix2dos

dpkg

dpkg [-ilCPru] [-F OPT ] PACKAGE

Install, remove and manage Debian packages

        -i,--install    Install the package
        -l,--list       List of installed packages
        --configure     Configure an unpackaged package
        -P,--purge      Purge all files of a package
        -r,--remove     Remove all but the configuration files for a package
        --unpack        Unpack a package, but don't configure it
        --force-depends Ignore dependency problems
        --force-confnew Overwrite existing config files when installing
        --force-confold Keep old config files when installing

dpkg-deb

dpkg-deb [-cefxX] FILE [argument

Perform actions on Debian packages (.debs)

        -c      List contents of filesystem tree
        -e      Extract control files to [argument] directory
        -f      Display control field name starting with [argument]
        -x      Extract packages filesystem tree to directory
        -X      Verbose extract

du

du [-aHLdclsxhmk] [ FILE ]...

Summarize disk space used for each FILE and/or directory

        -a      Show file sizes too
        -L      Follow all symlinks
        -H      Follow symlinks on command line
        -d N    Limit output to directories (and files with -a) of depth < N
        -c      Show grand total
        -l      Count sizes many times if hard linked
        -s      Display only a total for each argument
        -x      Skip directories on different filesystems
        -h      Sizes in human readable format (e.g., 1K 243M 2G)
        -m      Sizes in megabytes
        -k      Sizes in kilobytes (default)

dumpkmap

dumpkmap > keymap

Print a binary keyboard translation table to stdout

dumpleases

dumpleases [-r|-a] [-f LEASEFILE ]

Display DHCP leases granted by udhcpd

        -f,--file=FILE  Lease file
        -r,--remaining  Show remaining time
        -a,--absolute   Show expiration time

echo

echo [-neE] [ ARG ]...

Print the specified ARGs to stdout

        -n      Suppress trailing newline
        -e      Interpret backslash escapes (i.e., \t=tab)
        -E      Don't interpret backslash escapes (default)

ed

ed

env

env [-iu] [-] [name=value]... [ PROG ARGS ]

Print the current environment or run PROG after setting up the specified environment

        -, -i   Start with an empty environment
        -u      Remove variable from the environment

expand

expand [-i] [-t N] [ FILE ]...

Convert tabs to spaces, writing to stdout

        -i,--initial    Don't convert tabs after non blanks
        -t,--tabs=N     Tabstops every N chars

expr

expr EXPRESSION

Print the value of EXPRESSION to stdout

EXPRESSION may be:

        ARG1 | ARG2     ARG1 if it is neither null nor 0, otherwise ARG2
        ARG1 & ARG2     ARG1 if neither argument is null or 0, otherwise 0
        ARG1 < ARG2     1 if ARG1 is less than ARG2, else 0. Similarly:
        ARG1 <= ARG2
        ARG1 = ARG2
        ARG1 != ARG2
        ARG1 >= ARG2
        ARG1 > ARG2
        ARG1 + ARG2     Sum of ARG1 and ARG2. Similarly:
        ARG1 - ARG2
        ARG1 * ARG2
        ARG1 / ARG2
        ARG1 % ARG2
        STRING : REGEXP         Anchored pattern match of REGEXP in STRING
        match STRING REGEXP     Same as STRING : REGEXP
        substr STRING POS LENGTH Substring of STRING, POS counted from 1
        index STRING CHARS      Index in STRING where any CHARS is found, or 0
        length STRING           Length of STRING
        quote TOKEN             Interpret TOKEN as a string, even if
                                it is a keyword like 'match' or an
                                operator like '/'
        (EXPRESSION)            Value of EXPRESSION

Beware that many operators need to be escaped or quoted for shells. Comparisons are arithmetic if both ARGs are numbers, else lexicographical. Pattern matches return the string matched between \( and \) or null; if \( and \) are not used, they return the number of characters matched or 0.

false

false

Return an exit code of FALSE (1)

fdisk

fdisk [-ul] [-C CYLINDERS ] [-H HEADS ] [-S SECTORS ] [-b SSZ ] DISK

Change partition table

        -u              Start and End are in sectors (instead of cylinders)
        -l              Show partition table for each DISK, then exit
        -b 2048         (for certain MO disks) use 2048-byte sectors
        -C CYLINDERS    Set number of cylinders/heads/sectors
        -H HEADS
        -S SECTORS

find

find [ PATH ]... [ OPTIONS ] [ ACTIONS ]

Search for files and perform actions on them. First failed action stops processing of current file. Defaults: PATH is current directory, action is ’-print’

        -follow         Follow symlinks
        -xdev           Don't descend directories on other filesystems
        -maxdepth N     Descend at most N levels. -maxdepth 0 applies
                        actions to command line arguments only
        -mindepth N     Don't act on first N levels
        -depth          Act on directory *after* traversing it

Actions:

        ( ACTIONS )     Group actions for -o / -a
        ! ACT           Invert ACT's success/failure
        ACT1 [-a] ACT2  If ACT1 fails, stop, else do ACT2
        ACT1 -o ACT2    If ACT1 succeeds, stop, else do ACT2
                        Note: -a has higher priority than -o
        -name PATTERN   Match file name (w/o directory name) to PATTERN
        -iname PATTERN  Case insensitive -name
        -path PATTERN   Match path to PATTERN
        -ipath PATTERN  Case insensitive -path
        -regex PATTERN  Match path to regex PATTERN
        -type X         File type is X (one of: f,d,l,b,c,...)
        -perm MASK      At least one mask bit (+MASK), all bits (-MASK),
                        or exactly MASK bits are set in file's mode
        -mtime DAYS     mtime is greater than (+N), less than (-N),
                        or exactly N days in the past
        -mmin MINS      mtime is greater than (+N), less than (-N),
                        or exactly N minutes in the past
        -newer FILE     mtime is more recent than FILE's
        -inum N         File has inode number N
        -user NAME/ID   File is owned by given user
        -group NAME/ID  File is owned by given group
        -size N[bck]    File size is N (c:bytes,k:kbytes,b:512 bytes(def.))
                        +/-N: file size is bigger/smaller than N
        -links N        Number of links is greater than (+N), less than (-N),
                        or exactly N
        -prune          If current file is directory, don't descend into it
If none of the following actions is specified, -print is assumed
        -print          Print file name
        -print0         Print file name, NUL terminated
        -exec CMD ARG ; Run CMD with all instances of {} replaced by
                        file name. Fails if CMD exits with nonzero

fold

fold [-bs] [-w WIDTH ] [ FILE ]...

Wrap input lines in each FILE (or stdin), writing to stdout

        -b      Count bytes rather than columns
        -s      Break at spaces
        -w      Use WIDTH columns instead of 80

free

free [-b/k/m/g]

Display the amount of free and used system memory

freeramdisk

freeramdisk DEVICE

Free all memory used by the specified ramdisk

ftpget

ftpget [ OPTIONS ] HOST [ LOCAL_FILE ] REMOTE_FILE

Download a file via FTP

        -c,--continue           Continue previous transfer
        -v,--verbose            Verbose
        -u,--username USER      Username
        -p,--password PASS      Password
        -P,--port NUM           Port

ftpput

ftpput [ OPTIONS ] HOST [ REMOTE_FILE ] LOCAL_FILE

Upload a file to a FTP server

        -v,--verbose            Verbose
        -u,--username USER      Username
        -p,--password PASS      Password
        -P,--port NUM           Port

getopt

getopt [ OPTIONS ] [--] OPTSTRING PARAMS

        -a,--alternative                Allow long options starting with single -
        -l,--longoptions=LOPT[,...]     Long options to be recognized
        -n,--name=PROGNAME              The name under which errors are reported
        -o,--options=OPTSTRING          Short options to be recognized
        -q,--quiet                      Disable error reporting by getopt(3)
        -Q,--quiet-output               No normal output
        -s,--shell=SHELL                Set shell quoting conventions
        -T,--test                       Test for getopt(1) version
        -u,--unquoted                   Don't quote the output

Example:

O=’getopt -l bb: -- ab:c:: "$@"’ || exit 1 eval set -- "$O" while true; do case "$1" in -a) echo A; shift;; -b|--bb) echo "B:’$2’"; shift 2;; -c) case "$2" in "") echo C; shift 2;; *) echo "C:’$2’"; shift 2;; esac;; --) shift; break;; *) echo Error; exit 1;; esac done

getty

getty [ OPTIONS ] BAUD_RATE[,BAUD_RATE]... TTY [ TERMTYPE ]

Open TTY , prompt for login name, then invoke /bin/login

        -h              Enable hardware RTS/CTS flow control
        -L              Set CLOCAL (ignore Carrier Detect state)
        -m              Get baud rate from modem's CONNECT status message
        -n              Don't prompt for login name
        -w              Wait for CR or LF before sending /etc/issue
        -i              Don't display /etc/issue
        -f ISSUE_FILE   Display ISSUE_FILE instead of /etc/issue
        -l LOGIN        Invoke LOGIN instead of /bin/login
        -t SEC          Terminate after SEC if no login name is read
        -I INITSTR      Send INITSTR before anything else
        -H HOST         Log HOST into the utmp file as the hostname

BAUD_RATE of 0 leaves it unchanged

grep

grep [-HhnlLoqvsriwFEz] [-m N] [-A/B/C N] PATTERN/-e PATTERN .../-f FILE [ FILE ]...

Search for PATTERN in FILEs (or stdin)

        -H      Add 'filename:' prefix
        -h      Do not add 'filename:' prefix
        -n      Add 'line_no:' prefix
        -l      Show only names of files that match
        -L      Show only names of files that don't match
        -c      Show only count of matching lines
        -o      Show only the matching part of line
        -q      Quiet. Return 0 if PATTERN is found, 1 otherwise
        -v      Select non-matching lines
        -s      Suppress open and read errors
        -r      Recurse
        -i      Ignore case
        -w      Match whole words only
        -x      Match whole lines only
        -F      PATTERN is a literal (not regexp)
        -E      PATTERN is an extended regexp
        -z      Input is NUL terminated
        -m N    Match up to N times per file
        -A N    Print N lines of trailing context
        -B N    Print N lines of leading context
        -C N    Same as '-A N -B N'
        -e PTRN Pattern to match
        -f FILE Read pattern from file

groups

groups [ USER ]

Print the group memberships of USER or for the current process

gunzip

gunzip [-cft] [ FILE ]...

Decompress FILEs (or stdin)

        -c      Write to stdout
        -f      Force
        -t      Test file integrity

gzip

gzip [-cfd] [ FILE ]...

Compress FILEs (or stdin)

        -d      Decompress
        -c      Write to stdout
        -f      Force

halt

halt [-d DELAY ] [-n] [-f] [-w]

Halt the system

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (don't go through init)
        -w      Only write a wtmp record

head

head [ OPTIONS ] [ FILE ]...

Print first 10 lines of each FILE (or stdin) to stdout. With more than one FILE , precede each with a filename header.

        -n N[kbm]       Print first N lines
        -c N[kbm]       Print first N bytes
        -q              Never print headers
        -v              Always print headers

N may be suffixed by k (x1024), b (x512), or m (x1024^2).

hexdump

hexdump [-bcCdefnosvx] [ FILE ]...

Display FILEs (or stdin) in a user specified format

        -b              One-byte octal display
        -c              One-byte character display
        -C              Canonical hex+ASCII, 16 bytes per line
        -d              Two-byte decimal display
        -e FORMAT_STRING
        -f FORMAT_FILE
        -n LENGTH       Interpret only LENGTH bytes of input
        -o              Two-byte octal display
        -s OFFSET       Skip OFFSET bytes
        -v              Display all input data
        -x              Two-byte hexadecimal display

hostid

hostid

Print out a unique 32-bit identifier for the machine

hostname

hostname [ OPTIONS ] [ HOSTNAME | -F FILE ]

Get or set hostname or DNS domain name

        -s      Short
        -i      Addresses for the hostname
        -d      DNS domain name
        -f      Fully qualified domain name
        -F FILE Use FILE's content as hostname

httpd

httpd [-ifv[v]] [-c CONFFILE ] [-p [ IP: ]PORT] [-u USER[:GRP]] [-r REALM ] [-h HOME ] or httpd -d/-e/-m STRING

Listen for incoming HTTP requests

        -i              Inetd mode
        -f              Don't daemonize
        -v[v]           Verbose
        -p [IP:]PORT    Bind to IP:PORT (default *:80)
        -u USER[:GRP]   Set uid/gid after binding to port
        -r REALM        Authentication Realm for Basic Authentication
        -h HOME         Home directory (default .)
        -c FILE         Configuration file (default {/etc,HOME}/httpd.conf)
        -m STRING       MD5 crypt STRING
        -e STRING       HTML encode STRING
        -d STRING       URL decode STRING

hwclock

hwclock [-r|--show] [-s|--hctosys] [-w|--systohc] [-t|--systz] [-l|--localtime] [-u|--utc] [-f|--rtc FILE ]

Query and set hardware clock ( RTC )

        -r      Show hardware clock time
        -s      Set system time from hardware clock
        -w      Set hardware clock from system time
        -t      Set in-kernel timezone, correct system time
                if hardware clock is in local time
        -u      Assume hardware clock is kept in UTC
        -l      Assume hardware clock is kept in local time
        -f FILE Use specified device (e.g. /dev/rtc2)

id

id [ OPTIONS ] [ USER ]

Print information about USER or the current user

        -u      User ID
        -g      Group ID
        -G      Supplementary group IDs
        -n      Print names instead of numbers
        -r      Print real ID instead of effective ID

ifconfig

ifconfig [-a] interface [address]

Configure a network interface

        [add ADDRESS[/PREFIXLEN]]
        [del ADDRESS[/PREFIXLEN]]
        [[-]broadcast [ADDRESS]] [[-]pointopoint [ADDRESS]]
        [netmask ADDRESS] [dstaddr ADDRESS]
        [outfill NN] [keepalive NN]
        [hw ether|infiniband ADDRESS] [metric NN] [mtu NN]
        [[-]trailers] [[-]arp] [[-]allmulti]
        [multicast] [[-]promisc] [txqueuelen NN] [[-]dynamic]
        [mem_start NN] [io_addr NN] [irq NN]
        [up|down] ...

ifdown

ifdown [-anmvf] [-i FILE ] IFACE ...

        -a      De/configure all interfaces automatically
        -i FILE Use FILE for interface definitions
        -n      Print out what would happen, but don't do it
                (note: doesn't disable mappings)
        -m      Don't run any mappings
        -v      Print out what would happen before doing it
        -f      Force de/configuration

ifup

ifup [-anmvf] [-i FILE ] IFACE ...

        -a      De/configure all interfaces automatically
        -i FILE Use FILE for interface definitions
        -n      Print out what would happen, but don't do it
                (note: doesn't disable mappings)
        -m      Don't run any mappings
        -v      Print out what would happen before doing it
        -f      Force de/configuration

init

init

Init is the parent of all processes

insmod

insmod FILE [SYMBOL=VALUE]...

Load the specified kernel modules into the kernel

ionice

ionice [-c 1-3] [-n 0-7] [-p PID ] [ PROG ]

Change I/O priority and class

        -c      Class. 1:realtime 2:best-effort 3:idle
        -n      Priority

ip

ip [ OPTIONS ] {address | route | link | tunnel | rule} { COMMAND }

ip [ OPTIONS ] OBJECT { COMMAND } where OBJECT := {address | route | link | tunnel | rule} OPTIONS := { -f[amily] { inet | inet6 | link } | -o[neline] }

ipcalc

ipcalc [ OPTIONS ] ADDRESS[[/]NETMASK] [ NETMASK ]

Calculate IP network settings from a IP address

        -b,--broadcast  Display calculated broadcast address
        -n,--network    Display calculated network address
        -m,--netmask    Display default netmask for IP
        -p,--prefix     Display the prefix for IP/NETMASK
        -h,--hostname   Display first resolved host name
        -s,--silent     Don't ever display error messages

kill

kill [-l] [-SIG] PID ...

Send a signal (default: TERM ) to given PIDs

        -l      List all signal names and numbers

killall

killall [-l] [-q] [-SIG] PROCESS_NAME ...

Send a signal (default: TERM ) to given processes

        -l      List all signal names and numbers
        -q      Don't complain if no processes were killed

klogd

klogd [-c N] [-n]

Kernel logger

        -c N    Print to console messages more urgent than prio N (1-8)
        -n      Run in foreground

last

last

Show listing of the last users that logged into the system

less

less [-EMmNh~I?] [ FILE ]...

View FILE (or stdin) one screenful at a time

        -E      Quit once the end of a file is reached
        -M,-m   Display status line with line numbers
                and percentage through the file
        -N      Prefix line number to each line
        -I      Ignore case in all searches
        -~      Suppress ~s displayed past EOF

ln

ln [ OPTIONS ] TARGET ... LINK|DIR

Create a link LINK or DIR/TARGET to the specified TARGET (s)

        -s      Make symlinks instead of hardlinks
        -f      Remove existing destinations
        -n      Don't dereference symlinks - treat like normal file
        -b      Make a backup of the target (if exists) before link operation
        -S suf  Use suffix instead of ~ when making backup files

loadfont

loadfont < font

Load a console font from stdin

loadkmap

loadkmap < keymap

Load a binary keyboard translation table from stdin

logger

logger [ OPTIONS ] [ MESSAGE ]

Write MESSAGE (or stdin) to syslog

        -s      Log to stderr as well as the system log
        -t TAG  Log using the specified tag (defaults to user name)
        -p PRIO Priority (numeric or facility.level pair)

login

login [-p] [-h HOST ] [[-f] USER ]

Begin a new session on the system

        -f      Don't authenticate (user already authenticated)
        -h      Name of the remote host
        -p      Preserve environment

logname

logname

Print the name of the current user

logread

logread [-f]

Show messages in syslogd’s circular buffer

        -f      Output data as log grows

losetup

losetup [-r] [-o OFS ] LOOPDEV FILE - associate loop devices losetup -d LOOPDEV - disassociate losetup [-f] - show

        -o OFS  Start OFS bytes into FILE
        -r      Read-only
        -f      Show first free loop device

ls

ls [-1AaCxdLHRFplinsehrSXvctu] [-w WIDTH ] [ FILE ]...

List directory contents

        -1      One column output
        -a      Include entries which start with .
        -A      Like -a, but exclude . and ..
        -C      List by columns
        -x      List by lines
        -d      List directory entries instead of contents
        -L      Follow symlinks
        -H      Follow symlinks on command line
        -R      Recurse
        -p      Append / to dir entries
        -F      Append indicator (one of */=@|) to entries
        -l      Long listing format
        -i      List inode numbers
        -n      List numeric UIDs and GIDs instead of names
        -s      List allocated blocks
        -e      List full date and time
        -h      List sizes in human readable format (1K 243M 2G)
        -r      Sort in reverse order
        -S      Sort by size
        -X      Sort by extension
        -v      Sort by version
        -c      With -l: sort by ctime
        -t      With -l: sort by mtime
        -u      With -l: sort by atime
        -w N    Assume the terminal is N columns wide
        --color[={always,never,auto}]   Control coloring

lsmod

lsmod

List the currently loaded kernel modules

lzcat

lzcat FILE

Decompress to stdout

lzma

lzma -d [-cf] [ FILE ]...

Decompress FILE (or stdin)

        -d      Decompress
        -c      Write to stdout
        -f      Force

md5sum

md5sum [-c[sw]] [ FILE ]...

Print or check MD5 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

mdev

mdev [-s]

mdev -s is to be run during boot to scan /sys and populate /dev.

Bare mdev is a kernel hotplug helper. To activate it: echo /sbin/mdev >/proc/sys/kernel/hotplug

It uses /etc/mdev.conf with lines [-]DEVNAME UID:GID PERM [>|=PATH]|[!] [@|$|*PROG] where DEVNAME is device name regex, @major,minor[-minor2], or environment variable regex. A common use of the latter is to load modules for hotplugged devices:

        $MODALIAS=.* 0:0 660 @modprobe "$MODALIAS"

If /dev/mdev.seq file exists, mdev will wait for its value to match $SEQNUM variable. This prevents plug/unplug races. To activate this feature, create empty /dev/mdev.seq at boot.

microcom

microcom [-d DELAY ] [-t TIMEOUT ] [-s SPEED ] [-X] TTY

Copy bytes for stdin to TTY and from TTY to stdout

        -d      Wait up to DELAY ms for TTY output before sending every
                next byte to it
        -t      Exit if both stdin and TTY are silent for TIMEOUT ms
        -s      Set serial line to SPEED
        -X      Disable special meaning of NUL and Ctrl-X from stdin

mkdir

mkdir [ OPTIONS ] DIRECTORY ...

Create DIRECTORY

        -m MODE Mode
        -p      No error if exists; make parent directories as needed

mkfifo

mkfifo [-m MODE ] NAME

Create named pipe

        -m MODE Mode (default a=rw)

mknod

mknod [-m MODE ] NAME TYPE MAJOR MINOR

Create a special file (block, character, or pipe)

        -m MODE Creation mode (default a=rw)
TYPE:
        b       Block device
        c or u  Character device
        p       Named pipe (MAJOR and MINOR are ignored)

mkswap

mkswap [-L LBL ] BLOCKDEV [ KBYTES ]

Prepare BLOCKDEV to be used as swap partition

        -L LBL  Label

mktemp

mktemp [-dt] [-p DIR ] [ TEMPLATE ]

Create a temporary file with name based on TEMPLATE and print its name. TEMPLATE must end with XXXXXX (e.g. [/dir/]nameXXXXXX). Without TEMPLATE , -t tmp.XXXXXX is assumed.

        -d      Make directory, not file
        -t      Prepend base directory name to TEMPLATE
        -p DIR  Use DIR as a base directory (implies -t)
        -u      Do not create anything; print a name

Base directory is: -p DIR , else $TMPDIR, else /tmp

modinfo

modinfo [-adlp0] [-F keyword] MODULE

        -a              Shortcut for '-F author'
        -d              Shortcut for '-F description'
        -l              Shortcut for '-F license'
        -p              Shortcut for '-F parm'
        -F keyword      Keyword to look for
        -0              Separate output with NULs

modprobe

modprobe [-alrqvsDb] MODULE [symbol=value]...

        -a      Load multiple MODULEs
        -l      List (MODULE is a pattern)
        -r      Remove MODULE (stacks) or do autoclean
        -q      Quiet
        -v      Verbose
        -s      Log to syslog
        -D      Show dependencies
        -b      Apply blacklist to module names too

more

more [ FILE ]...

View FILE (or stdin) one screenful at a time

mount

mount [ OPTIONS ] [-o OPTS ] DEVICE NODE

Mount a filesystem. Filesystem autodetection requires /proc.

        -a              Mount all filesystems in fstab
        -f              Dry run
        -i              Don't run mount helper
        -r              Read-only mount
        -w              Read-write mount (default)
        -t FSTYPE[,...] Filesystem type(s)
        -O OPT          Mount only filesystems with option OPT (-a only)
-o OPT:
        loop            Ignored (loop devices are autodetected)
        [a]sync         Writes are [a]synchronous
        [no]atime       Disable/enable updates to inode access times
        [no]diratime    Disable/enable atime updates to directories
        [no]relatime    Disable/enable atime updates relative to modification time
        [no]dev         (Dis)allow use of special device files
        [no]exec        (Dis)allow use of executable files
        [no]suid        (Dis)allow set-user-id-root programs
        [r]shared       Convert [recursively] to a shared subtree
        [r]slave        Convert [recursively] to a slave subtree
        [r]private      Convert [recursively] to a private subtree
        [un]bindable    Make mount point [un]able to be bind mounted
        [r]bind         Bind a file or directory [recursively] to another location
        move            Relocate an existing mount point
        remount         Remount a mounted filesystem, changing flags
        ro/rw           Same as -r/-w

There are filesystem-specific -o flags.

mt

mt [-f device] opcode value

Control magnetic tape drive operation

Available Opcodes:

bsf bsfm bsr bss datacompression drvbuffer eof eom erase fsf fsfm fsr fss load lock mkpart nop offline ras1 ras2 ras3 reset retension rewind rewoffline seek setblk setdensity setpart tell unload unlock weof wset

mv

mv [-fin] SOURCE DEST or: mv [-fin] SOURCE ... DIRECTORY

Rename SOURCE to DEST , or move SOURCE (s) to DIRECTORY

        -f      Don't prompt before overwriting
        -i      Interactive, prompt before overwrite
        -n      Don't overwrite an existing file

nameif

nameif [-s] [-c FILE ] [ IFNAME HWADDR ]...

Rename network interface while it in the down state. The device with address HWADDR is renamed to IFACE .

        -c FILE Configuration file (default: /etc/mactab)
        -s      Log to syslog

nc

nc [-iN] [-wN] [-l] [-p PORT ] [-f FILE|IPADDR PORT ] [-e PROG ]

Open a pipe to IP:PORT or FILE

        -e PROG Run PROG after connect
        -l      Listen mode, for inbound connects
                (use -l twice with -e for persistent server)
        -p PORT Local port
        -w SEC  Timeout for connect
        -i SEC  Delay interval for lines sent
        -f FILE Use file (ala /dev/ttyS0) instead of network

netstat

netstat [-ral] [-tuwx] [-en]

Display networking information

        -r      Routing table
        -a      All sockets
        -l      Listening sockets
                Else: connected sockets
        -t      TCP sockets
        -u      UDP sockets
        -w      Raw sockets
        -x      Unix sockets
                Else: all socket types
        -e      Other/more information
        -n      Don't resolve names

nslookup

nslookup [ HOST ] [ SERVER ]

Query the nameserver for the IP address of the given HOST optionally using a specified DNS server

od

od [-abcdfhilovxs] [-t TYPE ] [-A RADIX ] [-N SIZE ] [-j SKIP ] [-S MINSTR ] [-w WIDTH ] [ FILE ...]

Print FILEs (or stdin) unambiguously, as octal bytes by default

openvt

openvt [-c N] [-sw] [ PROG ARGS ]

Start PROG on a new virtual terminal

        -c N    Use specified VT
        -s      Switch to the VT
        -w      Wait for PROG to exit

passwd

passwd [ OPTIONS ] [ USER ]

Change USER ’s password (default: current user)

        -a ALG  Encryption method
        -d      Set password to ''
        -l      Lock (disable) account
        -u      Unlock (enable) account

patch

patch [ OPTIONS ] [ ORIGFILE [ PATCHFILE ]]

        -p,--strip N            Strip N leading components from file names
        -i,--input DIFF         Read DIFF instead of stdin
        -R,--reverse            Reverse patch
        -N,--forward            Ignore already applied patches
        -E,--remove-empty-files Remove output files if they become empty

pidof

pidof [ NAME ]...

List PIDs of all processes with names that match NAMEs

ping

ping [ OPTIONS ] HOST

Send ICMP ECHO_REQUEST packets to network hosts

        -4,-6           Force IP or IPv6 name resolution
        -c CNT          Send only CNT pings
        -s SIZE         Send SIZE data bytes in packets (default:56)
        -t TTL          Set TTL
        -I IFACE/IP     Use interface or IP address as source
        -W SEC          Seconds to wait for the first response (default:10)
                        (after all -c CNT packets are sent)
        -w SEC          Seconds until ping exits (default:infinite)
                        (can exit earlier with -c CNT)
        -q              Quiet, only displays output at start
                        and when finished

ping6

ping6 [ OPTIONS ] HOST

Send ICMP ECHO_REQUEST packets to network hosts

        -c CNT          Send only CNT pings
        -s SIZE         Send SIZE data bytes in packets (default:56)
        -I IFACE/IP     Use interface or IP address as source
        -q              Quiet, only displays output at start
                        and when finished

pivot_root

pivot_root NEW_ROOT PUT_OLD

Move the current root file system to PUT_OLD and make NEW_ROOT the new root file system

poweroff

poweroff [-d DELAY ] [-n] [-f]

Halt and shut off power

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (don't go through init)

printf

printf FORMAT [ ARG ]...

Format and print ARG (s) according to FORMAT (a-la C printf)

ps

ps [-o COL1 ,COL2=HEADER] [-T]

Show list of processes

        -o COL1,COL2=HEADER     Select columns for display
        -T                      Show threads

pwd

pwd

Print the full filename of the current working directory

rdate

rdate [-sp] HOST

Get and possibly set the system date and time from a remote HOST

        -s      Set the system date and time (default)
        -p      Print the date and time

readlink

readlink [-fnv] FILE

Display the value of a symlink

        -f      Canonicalize by following all symlinks
        -n      Don't add newline
        -v      Verbose

realpath

realpath FILE ...

Return the absolute pathnames of given FILE

reboot

reboot [-d DELAY ] [-n] [-f]

Reboot the system

        -d SEC  Delay interval
        -n      Do not sync
        -f      Force (don't go through init)

renice

renice {{-n INCREMENT } | PRIORITY } [[-p | -g | -u] ID ...]

Change scheduling priority for a running process

        -n      Adjust current nice value (smaller is faster)
        -p      Process id(s) (default)
        -g      Process group id(s)
        -u      Process user name(s) and/or id(s)

reset

reset

Reset the screen

rev

rev [ FILE ]...

Reverse lines of FILE

rm

rm [-irf] FILE ...

Remove (unlink) FILEs

        -i      Always prompt before removing
        -f      Never prompt
        -R,-r   Recurse

rmdir

rmdir [ OPTIONS ] DIRECTORY ...

Remove DIRECTORY if it is empty

        -p|--parents    Include parents
        --ignore-fail-on-non-empty

rmmod

rmmod [-wfa] [ MODULE ]...

Unload kernel modules

        -w      Wait until the module is no longer used
        -f      Force unload
        -a      Remove all unused modules (recursively)

route

route [{add|del|delete}]

Edit kernel routing tables

        -n      Don't resolve names
        -e      Display other/more information
        -A inet{6}      Select address family

rpm

rpm -i PACKAGE .rpm; rpm -qp[ildc] PACKAGE .rpm

Manipulate RPM packages

Commands:

        -i      Install package
        -qp     Query package
        -i      Show information
        -l      List contents
        -d      List documents
        -c      List config files

rpm2cpio

rpm2cpio package.rpm

Output a cpio archive of the rpm file

run-parts

run-parts [-t] [-a ARG ] [-u MASK ] DIRECTORY

Run a bunch of scripts in DIRECTORY

        -t      Print what would be run, but don't actually run anything
        -a ARG  Pass ARG as argument for every program
        -u MASK Set the umask to MASK before running every program

sed

sed [-inr] [-f FILE ]... [-e CMD ]... [ FILE ]... or: sed [-inr] CMD [ FILE ]...

        -e CMD  Add CMD to sed commands to be executed
        -f FILE Add FILE contents to sed commands to be executed
        -i      Edit files in-place (else sends result to stdout)
        -n      Suppress automatic printing of pattern space
        -r      Use extended regex syntax

If no -e or -f, the first non-option argument is the sed command string. Remaining arguments are input files (stdin if none).

seq

seq [-w] [-s SEP ] [ FIRST [ INC ]] LAST

Print numbers from FIRST to LAST , in steps of INC . FIRST , INC default to 1.

        -w      Pad to last with leading zeros
        -s SEP  String separator

setkeycodes

setkeycodes SCANCODE KEYCODE ...

Set entries into the kernel’s scancode-to-keycode map, allowing unusual keyboards to generate usable keycodes.

SCANCODE may be either xx or e0xx (hexadecimal), and KEYCODE is given in decimal.

setsid

setsid PROG ARGS

Run PROG in a new session. PROG will have no controlling terminal and will not be affected by keyboard signals (Ctrl-C etc). See setsid(2) for details.

sh

sh [-/+OPTIONS] [-/+o OPT ]... [-c ’ SCRIPT ’ [ ARG0 [ ARGS ]] / FILE [ ARGS ]]

Unix shell interpreter

sha1sum

sha1sum [-c[sw]] [ FILE ]...

Print or check SHA1 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

sha256sum

sha256sum [-c[sw]] [ FILE ]...

Print or check SHA256 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

sha512sum

sha512sum [-c[sw]] [ FILE ]...

Print or check SHA512 checksums

        -c      Check sums against list in FILEs
        -s      Don't output anything, status code shows success
        -w      Warn about improperly formatted checksum lines

sleep

sleep [N]...

Pause for a time equal to the total of the args given, where each arg can have an optional suffix of (s)econds, (m)inutes, (h)ours, or (d)ays

sort

sort [-nrugMcszbdfimSTokt] [-o FILE ] [-k start[.offset][opts][,end[.offset][opts]] [-t CHAR ] [ FILE ]...

Sort lines of text

        -b      Ignore leading blanks
        -c      Check whether input is sorted
        -d      Dictionary order (blank or alphanumeric only)
        -f      Ignore case
        -g      General numerical sort
        -i      Ignore unprintable characters
        -k      Sort key
        -M      Sort month
        -n      Sort numbers
        -o      Output to file
        -k      Sort by key
        -t CHAR Key separator
        -r      Reverse sort order
        -s      Stable (don't sort ties alphabetically)
        -u      Suppress duplicate lines
        -z      Lines are terminated by NUL, not newline
        -mST    Ignored for GNU compatibility

start-stop-daemon

start-stop-daemon [ OPTIONS ] [-S|-K] ... [-- ARGS ...]

Search for matching processes, and then -K: stop all matching processes. -S: start a process unless a matching process is found.

Process matching:

        -u,--user USERNAME|UID  Match only this user's processes
        -n,--name NAME          Match processes with NAME
                                in comm field in /proc/PID/stat
        -x,--exec EXECUTABLE    Match processes with this command
                                in /proc/PID/{exe,cmdline}
        -p,--pidfile FILE       Match a process with PID from the file
        All specified conditions must match
-S only:
        -x,--exec EXECUTABLE    Program to run
        -a,--startas NAME       Zeroth argument
        -b,--background         Background
        -N,--nicelevel N        Change nice level
        -c,--chuid USER[:[GRP]] Change to user/group
        -m,--make-pidfile       Write PID to the pidfile specified by -p
-K only:
        -s,--signal SIG         Signal to send
        -t,--test               Match only, exit with 0 if a process is found
Other:
        -o,--oknodo             Exit with status 0 if nothing is done
        -v,--verbose            Verbose
        -q,--quiet              Quiet

stat

stat [ OPTIONS ] FILE ...

Display file (default) or filesystem status

        -c fmt  Use the specified format
        -f      Display filesystem status
        -L      Follow links
        -t      Display info in terse form

Valid format sequences for files:

 %a     Access rights in octal
 %A     Access rights in human readable form
 %b     Number of blocks allocated (see %B)
 %B     The size in bytes of each block reported by %b
 %d     Device number in decimal
 %D     Device number in hex
 %f     Raw mode in hex
 %F     File type
 %g     Group ID of owner
 %G     Group name of owner
 %h     Number of hard links
 %i     Inode number
 %n     File name
 %N     File name, with -> TARGET if symlink
 %o     I/O block size
 %s     Total size, in bytes
 %t     Major device type in hex
 %T     Minor device type in hex
 %u     User ID of owner
 %U     User name of owner
 %x     Time of last access
 %X     Time of last access as seconds since Epoch
 %y     Time of last modification
 %Y     Time of last modification as seconds since Epoch
 %z     Time of last change
 %Z     Time of last change as seconds since Epoch

Valid format sequences for file systems:

 %a     Free blocks available to non-superuser
 %b     Total data blocks in file system
 %c     Total file nodes in file system
 %d     Free file nodes in file system
 %f     Free blocks in file system
 %i     File System ID in hex
 %l     Maximum length of filenames
 %n     File name
 %s     Block size (for faster transfer)
 %S     Fundamental block size (for block counts)
 %t     Type in hex
 %T     Type in human readable form

strings

strings [-afo] [-n LEN ] [ FILE ]...

Display printable strings in a binary file

        -a      Scan whole file (default)
        -f      Precede strings with filenames
        -n LEN  At least LEN characters form a string (default 4)
        -o      Precede strings with decimal offsets

stty

stty [-a|g] [-F DEVICE ] [ SETTING ]...

Without arguments, prints baud rate, line discipline, and deviations from stty sane

        -F DEVICE       Open device instead of stdin
        -a              Print all current settings in human-readable form
        -g              Print in stty-readable form
        [SETTING]       See manpage

su

su [ OPTIONS ] [-] [ USER ]

Run shell under USER (by default, root)

        -,-l    Clear environment, run shell as login shell
        -p,-m   Do not set new $HOME, $SHELL, $USER, $LOGNAME
        -c CMD  Command to pass to 'sh -c'
        -s SH   Shell to use instead of user's default

sulogin

sulogin [-t N] [ TTY ]

Single user login

        -t N    Timeout

swapoff

swapoff [-a] [ DEVICE ]

Stop swapping on DEVICE

        -a      Stop swapping on all swap devices

swapon

swapon [-a] [ DEVICE ]

Start swapping on DEVICE

        -a      Start swapping on all swap devices

switch_root

switch_root [-c /dev/console] NEW_ROOT NEW_INIT [ ARGS ]

Free initramfs and switch to another root fs:

chroot to NEW_ROOT , delete all in /, move NEW_ROOT to /, execute NEW_INIT . PID must be 1. NEW_ROOT must be a mountpoint.

        -c DEV  Reopen stdio to DEV after switch

sync

sync

Write all buffered blocks to disk

sysctl

sysctl [ OPTIONS ] [ VALUE ]...

Configure kernel parameters at runtime

        -n      Don't print key names
        -e      Don't warn about unknown keys
        -w      Change sysctl setting
        -p FILE Load sysctl settings from FILE (default /etc/sysctl.conf)
        -a      Display all values
        -A      Display all values in table form

syslogd

syslogd [ OPTIONS ]

System logging utility (this version of syslogd ignores /etc/syslog.conf)

        -n              Run in foreground
        -O FILE         Log to FILE (default:/var/log/messages)
        -l N            Log only messages more urgent than prio N (1-8)
        -S              Smaller output
        -R HOST[:PORT]  Log to IP or hostname on PORT (default PORT=514/UDP)
        -L              Log locally and via network (default is network only if -R)
        -C[size_kb]     Log to shared mem buffer (use logread to read it)

tac

tac [ FILE ]...

Concatenate FILEs and print them in reverse

tail

tail [ OPTIONS ] [ FILE ]...

Print last 10 lines of each FILE (or stdin) to stdout. With more than one FILE , precede each with a filename header.

        -f              Print data as file grows
        -s SECONDS      Wait SECONDS between reads with -f
        -n N[kbm]       Print last N lines
        -c N[kbm]       Print last N bytes
        -q              Never print headers
        -v              Always print headers

N may be suffixed by k (x1024), b (x512), or m (x1024^2). If N starts with a ’+’, output begins with the Nth item from the start of each file, not from the end.

tar

tar -[cxtZzjahmvO] [-f TARFILE ] [-C DIR ] [ FILE ]...

Create, extract, or list files from a tar file

Operation:

        c       Create
        x       Extract
        t       List
        f       Name of TARFILE ('-' for stdin/out)
        C       Change to DIR before operation
        v       Verbose
        Z       (De)compress using compress
        z       (De)compress using gzip
        j       (De)compress using bzip2
        a       (De)compress using lzma
        O       Extract to stdout
        h       Follow symlinks
        m       Don't restore mtime

taskset

taskset [-p] [ MASK ] [ PID | PROG ARGS ]

Set or get CPU affinity

        -p      Operate on an existing PID

tee

tee [-ai] [ FILE ]...

Copy stdin to each FILE , and also to stdout

        -a      Append to the given FILEs, don't overwrite
        -i      Ignore interrupt signals (SIGINT)

telnet

telnet [-a] [-l USER ] HOST [ PORT ]

Connect to telnet server

        -a      Automatic login with $USER variable
        -l USER Automatic login as USER

telnetd

telnetd [ OPTIONS ]

Handle incoming telnet connections

        -l LOGIN        Exec LOGIN on connect
        -f ISSUE_FILE   Display ISSUE_FILE instead of /etc/issue
        -K              Close connection as soon as login exits
                        (normally wait until all programs close slave pty)
        -p PORT         Port to listen on
        -b ADDR[:PORT]  Address to bind to
        -F              Run in foreground
        -i              Inetd mode

test

test EXPRESSION ]

Check file types, compare values etc. Return a 0/1 exit code depending on logical value of EXPRESSION

tftp

tftp [ OPTIONS ] HOST [ PORT ]

Transfer a file from/to tftp server

        -l FILE Local FILE
        -r FILE Remote FILE
        -g      Get file
        -p      Put file
        -b SIZE Transfer blocks of SIZE octets

time

time [-v] PROG ARGS

Run PROG , display resource usage when it exits

        -v      Verbose

timeout

timeout [-t SECS ] [-s SIG ] PROG ARGS

Runs PROG . Sends SIG to it if it is not gone in SECS seconds. Defaults: SECS: 10, SIG: TERM .

top

top [-b] [-nCOUNT] [-dSECONDS]

Provide a view of process activity in real time. Read the status of all processes from /proc each SECONDS and display a screenful of them. Keys:

        N/M/P/T: sort by pid/mem/cpu/time
        R: reverse sort
        H: toggle threads
        Q,^C: exit

Options:

        -b      Batch mode
        -n N    Exit after N iterations
        -d N    Delay between updates

touch

touch [-c] [-d DATE ] [-t DATE ] [-r FILE ] FILE ...

Update the last-modified date on the given FILE[s]

        -c      Don't create files
        -d DT   Date/time to use
        -t DT   Date/time to use
        -r FILE Use FILE's date/time

tr

tr [-cds] STRING1 [ STRING2 ]

Translate, squeeze, or delete characters from stdin, writing to stdout

        -c      Take complement of STRING1
        -d      Delete input characters coded STRING1
        -s      Squeeze multiple output characters of STRING2 into one character

traceroute

traceroute [-46FIldnrv] [-f 1ST_TTL] [-m MAXTTL ] [-p PORT ] [-q PROBES ] [-s SRC_IP ] [-t TOS ] [-w WAIT_SEC ] [-g GATEWAY ] [-i IFACE ] [-z PAUSE_MSEC ] HOST [ BYTES ]

Trace the route to HOST

        -4,-6   Force IP or IPv6 name resolution
        -F      Set the don't fragment bit
        -I      Use ICMP ECHO instead of UDP datagrams
        -l      Display the TTL value of the returned packet
        -d      Set SO_DEBUG options to socket
        -n      Print numeric addresses
        -r      Bypass routing tables, send directly to HOST
        -v      Verbose
        -m      Max time-to-live (max number of hops)
        -p      Base UDP port number used in probes
                (default 33434)
        -q      Number of probes per TTL (default 3)
        -s      IP address to use as the source address
        -t      Type-of-service in probe packets (default 0)
        -w      Time in seconds to wait for a response (default 3)
        -g      Loose source route gateway (8 max)

traceroute6

traceroute6 [-dnrv] [-m MAXTTL ] [-p PORT ] [-q PROBES ] [-s SRC_IP ] [-t TOS ] [-w WAIT_SEC ] [-i IFACE ] HOST [ BYTES ]

Trace the route to HOST

        -d      Set SO_DEBUG options to socket
        -n      Print numeric addresses
        -r      Bypass routing tables, send directly to HOST
        -v      Verbose
        -m      Max time-to-live (max number of hops)
        -p      Base UDP port number used in probes
                (default is 33434)
        -q      Number of probes per TTL (default 3)
        -s      IP address to use as the source address
        -t      Type-of-service in probe packets (default 0)
        -w      Time in seconds to wait for a response (default 3)

true

true

Return an exit code of TRUE (0)

tty

tty

Print file name of stdin’s terminal

        -s      Print nothing, only return exit status

tunctl

tunctl [-f device] ([-t name] | -d name)

Create or delete tun interfaces

        -f name         tun device (/dev/net/tun)
        -t name         Create iface 'name'
        -d name         Delete iface 'name'

udhcpc

udhcpc [-fbnqoCRB] [-i IFACE ] [-r IP ] [-s PROG ] [-p PIDFILE ] [-V VENDOR ] [-x OPT:VAL ]... [-O OPT ]...

        -i,--interface IFACE    Interface to use (default eth0)
        -p,--pidfile FILE       Create pidfile
        -s,--script PROG        Run PROG at DHCP events (default /etc/udhcpc/default.script)
        -B,--broadcast          Request broadcast replies
        -t,--retries N          Send up to N discover packets
        -T,--timeout N          Pause between packets (default 3 seconds)
        -A,--tryagain N         Wait N seconds after failure (default 20)
        -f,--foreground         Run in foreground
        -b,--background         Background if lease is not obtained
        -n,--now                Exit if lease is not obtained
        -q,--quit               Exit after obtaining lease
        -R,--release            Release IP on exit
        -S,--syslog             Log to syslog too
        -a,--arping             Use arping to validate offered address
        -O,--request-option OPT Request option OPT from server (cumulative)
        -o,--no-default-options Don't request any options (unless -O is given)
        -r,--request IP         Request this IP address
        -x OPT:VAL              Include option OPT in sent packets (cumulative)
                                Examples of string, numeric, and hex byte opts:
                                -x hostname:bbox - option 12
                                -x lease:3600 - option 51 (lease time)
                                -x 0x3d:0100BEEFC0FFEE - option 61 (client id)
        -F,--fqdn NAME          Ask server to update DNS mapping for NAME
        -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')
        -C,--clientid-none      Don't send MAC as client identifier
Signals:
        USR1    Renew lease
        USR2    Release lease

udhcpd

udhcpd [-fS] [ CONFFILE ]

DHCP server

        -f      Run in foreground
        -S      Log to syslog too

umount

umount [ OPTIONS ] FILESYSTEM|DIRECTORY

Unmount file systems

        -a      Unmount all file systems
        -r      Try to remount devices as read-only if mount is busy
        -l      Lazy umount (detach filesystem)
        -f      Force umount (i.e., unreachable NFS server)
        -D      Don't free loop device even if it has been used

uname

uname [-amnrspv]

Print system information

        -a      Print all
        -m      The machine (hardware) type
        -n      Hostname
        -r      OS release
        -s      OS name (default)
        -p      Processor type
        -v      OS version

uncompress

uncompress [-cf] [ FILE ]...

Decompress .Z file[s]

        -c      Write to stdout
        -f      Overwrite

unexpand

unexpand [-fa][-t N] [ FILE ]...

Convert spaces to tabs, writing to stdout

        -a,--all        Convert all blanks
        -f,--first-only Convert only leading blanks
        -t,--tabs=N     Tabstops every N chars

uniq

uniq [-cdu][-f,s,w N] [ INPUT [ OUTPUT ]]

Discard duplicate lines

        -c      Prefix lines by the number of occurrences
        -d      Only print duplicate lines
        -u      Only print unique lines
        -f N    Skip first N fields
        -s N    Skip first N chars (after any skipped fields)
        -w N    Compare N characters in line

unix2dos

unix2dos [-ud] [ FILE ]

Convert FILE in-place from Unix to DOS format. When no file is given, use stdin/stdout.

        -u      dos2unix
        -d      unix2dos

unlzma

unlzma [-cf] [ FILE ]...

Decompress FILE (or stdin)

        -c      Write to stdout
        -f      Force

unxz

unxz [-cf] [ FILE ]...

Decompress FILE (or stdin)

        -c      Write to stdout
        -f      Force

unzip

unzip [-opts[modifiers]] FILE[.zip] [ LIST ] [-x XLIST ] [-d DIR ]

Extract files from ZIP archives

        -l      List archive contents (with -q for short form)
        -n      Never overwrite files (default)
        -o      Overwrite
        -p      Send output to stdout
        -q      Quiet
        -x XLST Exclude these files
        -d DIR  Extract files into DIR

uptime

uptime

Display the time since the last boot

usleep

usleep N

Pause for N microseconds

uudecode

uudecode [-o OUTFILE ] [ INFILE ]

Uudecode a file Finds OUTFILE in uuencoded source unless -o is given

uuencode

uuencode [-m] [ FILE ] STORED_FILENAME

Uuencode FILE (or stdin) to stdout

        -m      Use base64 encoding per RFC1521

vconfig

vconfig COMMAND [ OPTIONS ]

Create and remove virtual ethernet devices

        add             IFACE VLAN_ID
        rem             VLAN_NAME
        set_flag        IFACE 0|1 VLAN_QOS
        set_egress_map  VLAN_NAME SKB_PRIO VLAN_QOS
        set_ingress_map VLAN_NAME SKB_PRIO VLAN_QOS
        set_name_type   NAME_TYPE

vi

vi [ OPTIONS ] [ FILE ]...

Edit FILE

        -c      Initial command to run ($EXINIT also available)
        -R      Read-only
        -H      Short help regarding available features

watch

watch [-n SEC ] [-t] PROG ARGS

Run PROG periodically

        -n      Loop period in seconds (default 2)
        -t      Don't print header

watchdog

watchdog [-t N[ms]] [-T N[ms]] [-F] DEV

Periodically write to watchdog device DEV

        -T N    Reboot after N seconds if not reset (default 60)
        -t N    Reset every N seconds (default 30)
        -F      Run in foreground

Use 500ms to specify period in milliseconds

wc

wc [-cmlwL] [ FILE ]...

Count lines, words, and bytes for each FILE (or stdin)

        -c      Count bytes
        -m      Count characters
        -l      Count newlines
        -w      Count words
        -L      Print longest line length

wget

wget [-c|--continue] [-s|--spider] [-q|--quiet] [-O|--output-document FILE ] [--header ’header: value’] [-Y|--proxy on/off] [-P DIR ] [--no-check-certificate] [-U|--user-agent AGENT ] URL ...

Retrieve files via HTTP or FTP

        -s      Spider mode - only check file existence
        -c      Continue retrieval of aborted transfer
        -q      Quiet
        -P DIR  Save to DIR (default .)
        -O FILE Save to FILE ('-' for stdout)
        -U STR  Use STR for User-Agent header
        -Y      Use proxy ('on' or 'off')

which

which [ COMMAND ]...

Locate a COMMAND

who

who [-a]

Show who is logged on

        -a      Show all
        -H      Print column headers

whoami

whoami

Print the user name associated with the current effective user id

xargs

xargs [ OPTIONS ] [ PROG ARGS ]

Run PROG on every item given by stdin

        -p      Ask user whether to run each command
        -r      Don't run command if input is empty
        -0      Input is separated by NUL characters
        -t      Print the command on stderr before execution
        -e[STR] STR stops input processing
        -n N    Pass no more than N args to PROG
        -s N    Pass command line of no more than N bytes
        -x      Exit if size is exceeded

xz

xz -d [-cf] [ FILE ]...

Decompress FILE (or stdin)

        -d      Decompress
        -c      Write to stdout
        -f      Force

xzcat

xzcat FILE

Decompress to stdout

yes

yes [ STRING ]

Repeatedly output a line with STRING , or ’y’

zcat

zcat FILE

Decompress to stdout

common options

Most BusyBox applets support the --help argument to provide a terse runtime description of their behavior. If the CONFIG_FEATURE_VERBOSE_USAGE option has been enabled, more detailed usage information will also be available.

libc nss

GNU Libc (glibc) uses the Name Service Switch ( NSS ) to configure the behavior of the C library for the local environment, and to configure how it reads system data, such as passwords and group information. This is implemented using an /etc/nsswitch.conf configuration file, and using one or more of the /lib/libnss_* libraries. BusyBox tries to avoid using any libc calls that make use of NSS . Some applets however, such as login and su, will use libc functions that require NSS .

If you enable CONFIG_USE_BB_PWD_GRP , BusyBox will use internal functions to directly access the /etc/passwd, /etc/group, and /etc/shadow files without using NSS . This may allow you to run your system without the need for installing any of the NSS configuration files and libraries.

When used with glibc, the BusyBox ’networking’ applets will similarly require that you install at least some of the glibc NSS stuff (in particular, /etc/nsswitch.conf, /lib/libnss_dns*, /lib/libnss_files*, and /lib/libresolv*).

Shameless Plug: As an alternative, one could use a C library such as uClibc. In addition to making your system significantly smaller, uClibc does not require the use of any NSS support files or libraries.

maintainer

Denis Vlasenko <vda.linux[:at:]googlemail[:dot:]com>

syntax

 busybox <applet> [arguments...]  # or
 <applet> [arguments...]          # if symlinked

usage

BusyBox is a multi-call binary. A multi-call binary is an executable program that performs the same job as more than one utility program. That means there is just a single BusyBox binary, but that single binary acts like a large number of utilities. This allows BusyBox to be smaller since all the built-in utility programs (we call them applets) can share code for many common operations.

You can also invoke BusyBox by issuing a command as an argument on the command line. For example, entering

        /bin/busybox ls

will also cause BusyBox to behave as ’ls’.

Of course, adding ’/bin/busybox’ into every command would be painful. So most people will invoke BusyBox using links to the BusyBox binary.

For example, entering

        ln -s /bin/busybox ls
        ./ls

will cause BusyBox to behave as ’ls’ (if the ’ls’ command has been compiled into BusyBox). Generally speaking, you should never need to make all these links yourself, as the BusyBox build system will do this for you when you run the ’make install’ command.

If you invoke BusyBox with no arguments, it will provide you with a list of the applets that have been compiled into your BusyBox binary.


authors

The following people have contributed code to BusyBox whether they know it or not. If you have written code included in BusyBox, you should probably be listed here so you can obtain your bit of eternal glory. If you should be listed here, or the description of what you have done needs more detail, or is incorrect, please send in an update.

Emanuele Aina <emanuele.aina[:at:]tiscali[:dot:]it>
run-parts

Erik Andersen <andersen[:at:]codepoet[:dot:]org>

    Tons of new stuff, major rewrite of most of the
    core apps, tons of new apps as noted in header files.
    Lots of tedious effort writing these boring docs that
    nobody is going to actually read.

Laurence Anderson <l.d.anderson[:at:]warwick.ac[:dot:]uk>

    rpm2cpio, unzip, get_header_cpio, read_gz interface, rpm

Jeff Angielski <jeff[:at:]theptrgroup[:dot:]com>

    ftpput, ftpget

Edward Betts <edward[:at:]debian[:dot:]org>

    expr, hostid, logname, whoami

John Beppu <beppu[:at:]codepoet[:dot:]org>

    du, nslookup, sort

Brian Candler <B.Candler[:at:]pobox[:dot:]com>

    tiny-ls(ls)

Randolph Chung <tausq[:at:]debian[:dot:]org>

    fbset, ping, hostname

Dave Cinege <dcinege[:at:]psychosis[:dot:]com>

    more(v2), makedevs, dutmp, modularization, auto links file,
    various fixes, Linux Router Project maintenance

Jordan Crouse <jordan[:at:]cosmicpenguin[:dot:]net>

    ipcalc

Magnus Damm <damm[:at:]opensource[:dot:]se>

    tftp client insmod powerpc support

Larry Doolittle <ldoolitt[:at:]recycle.lbl[:dot:]gov>

    pristine source directory compilation, lots of patches and fixes.

Glenn Engel <glenne[:at:]engel[:dot:]org>

    httpd

Gennady Feldman <gfeldman[:at:]gena01[:dot:]com>

    Sysklogd (single threaded syslogd, IPC Circular buffer support,
    logread), various fixes.

Karl M. Hegbloom <karlheg[:at:]debian[:dot:]org>

    cp_mv.c, the test suite, various fixes to utility.c, &c.

Daniel Jacobowitz <dan[:at:]debian[:dot:]org>

    mktemp.c

Matt Kraai <kraai[:at:]alumni.cmu[:dot:]edu>

    documentation, bugfixes, test suite

Stephan Linz <linz@li-pro.net>

    ipcalc, Red Hat equivalence

John Lombardo <john[:at:]deltanet[:dot:]com>

    tr

Glenn McGrath <bug1[:at:]iinet.net[:dot:]au>

    Common unarchiving code and unarchiving applets, ifupdown, ftpgetput,
    nameif, sed, patch, fold, install, uudecode.
    Various bugfixes, review and apply numerous patches.

Manuel Novoa III <mjn3[:at:]codepoet[:dot:]org>

    cat, head, mkfifo, mknod, rmdir, sleep, tee, tty, uniq, usleep, wc, yes,
    mesg, vconfig, make_directory, parse_mode, dirname, mode_string,
    get_last_path_component, simplify_path, and a number trivial libbb routines
    also bug fixes, partial rewrites, and size optimizations in
    ash, basename, cal, cmp, cp, df, du, echo, env, ln, logname, md5sum, mkdir,
    mv, realpath, rm, sort, tail, touch, uname, watch, arith, human_readable,
    interface, dutmp, ifconfig, route

Vladimir Oleynik <dzo[:at:]simtreas[:dot:]ru>

    cmdedit; xargs(current), httpd(current);
    ports: ash, crond, fdisk, inetd, stty, traceroute, top;
    locale, various fixes
    and irreconcilable critic of everything not perfect.

Bruce Perens <bruce[:at:]pixar[:dot:]com>

    Original author of BusyBox in 1995, 1996. Some of his code can
    still be found hiding here and there...

Tim Riker <Tim[:at:]Rikers[:dot:]org>

    bug fixes, member of fan club

Kent Robotti <robotti[:at:]metconnect[:dot:]com>

    reset, tons and tons of bug reports and patches.

Chip Rosenthal <chip[:at:]unicom[:dot:]com>, <crosenth[:at:]covad[:dot:]com>

    wget - Contributed by permission of Covad Communications

Pavel Roskin <proski[:at:]gnu[:dot:]org>

    Lots of bugs fixes and patches.

Gyepi Sam <gyepi@praxis-sw.com>

    Remote logging feature for syslogd

Linus Torvalds <torvalds[:at:]transmeta[:dot:]com>

    mkswap, fsck.minix, mkfs.minix

Mark Whitley <markw[:at:]codepoet[:dot:]org>

    grep, sed, cut, xargs(previous),
    style-guide, new-applet-HOWTO, bug fixes, etc.

Charles P. Wright <cpwright[:at:]villagenet[:dot:]com>

    gzip, mini-netcat(nc)

Enrique Zanardi <ezanardi[:at:]ull[:dot:]es>

    tarcat (since removed), loadkmap, various fixes, Debian maintenance

Tito Ragusa <farmatito[:at:]tiscali[:dot:]it>

    devfsd and size optimizations in strings, openvt and deallocvt.

Paul Fox <pgf[:at:]foxharp.boston.ma[:dot:]us>

    vi editing mode for ash, various other patches/fixes

Roberto A. Foglietta <me[:at:]roberto.foglietta[:dot:]name>

    port: dnsd

Bernhard Reutner-Fischer <rep.dot.nop[:at:]gmail[:dot:]com>

    misc

Mike Frysinger <vapier[:at:]gentoo[:dot:]org>

    initial e2fsprogs, printenv, setarch, sum, misc

Jie Zhang <jie.zhang[:at:]analog[:dot:]com>

    fixed two bugs in msh and hush (exitcode of killed processes)

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