NAME

BusyBox - The Swiss Army Knife of Embedded Linux

SYNTAX

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

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

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.

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.

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.

COMMANDS

Currently available applets include:

[, [[, ar, arch, ascii, ash, awk, base32, base64, basename, bash,
bc, bunzip2, busybox, bzcat, bzip2, cal, cat, chattr, chmod, cksum,
clear, cmp, comm, cp, cpio, crc32, cut, date, dc, dd, df, diff,
dirname, dos2unix, dpkg, dpkg-deb, du, echo, ed, egrep, env, expand,
expr, factor, false, fgrep, find, fold, free, fsync, ftpget, ftpput,
getopt, grep, groups, gunzip, gzip, hd, head, hexdump, httpd, iconv,
id, inotifyd, install, ipcalc, jn, kill, killall, less, link, ln,
logname, ls, lsattr, lzcat, lzma, lzop, lzopcat, man, md5sum, mkdir,
mktemp, mv, nc, nl, nproc, od, paste, patch, pgrep, pidof,
pipe_progress, pkill, printenv, printf, ps, pwd, readlink, realpath,
reset, rev, rm, rmdir, rpm, rpm2cpio, sed, seq, sh, sha1sum,
sha256sum, sha3sum, sha512sum, shred, shuf, sleep, sort, split,
ssl_client, stat, strings, su, sum, sync, tac, tail, tar, tee, test,
time, timeout, touch, tr, true, truncate, ts, tsort, ttysize, uname,
uncompress, unexpand, uniq, unix2dos, unlink, unlzma, unlzop, unxz,
unzip, uptime, usleep, uudecode, uuencode, vi, watch, wc, wget,
which, whoami, whois, xargs, xxd, xz, xzcat, yes, zcat

COMMAND DESCRIPTIONS

ar

ar x|p|t|r [-ov] ARCHIVE [FILE]...

Extract or list FILEs from an ar archive, or create it

x       Extract
p       Extract to stdout
t       List
r       Create
-o      Restore mtime
-v      Verbose
arch

arch

Print system architecture

ash

ash [-il] [-|+Cabefmnuvx] [-|+o OPT]... [-c 'SCRIPT' [ARG0 ARGS] | FILE ARGS | -s 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
-e AWK_PROGRAM
base32

base32 [-d] [-w COL] [FILE]

Base32 encode or decode FILE to standard output

-d      Decode data
-w COL  Wrap lines at COL (default 76, 0 disables)
base64

base64 [-d] [-w COL] [FILE]

Base64 encode or decode FILE to standard output

-d      Decode data
-w COL  Wrap lines at COL (default 76, 0 disables)
basename

basename FILE [SUFFIX] | -a FILE... | -s SUFFIX FILE...

Strip directory path and SUFFIX from FILE

-a              All arguments are FILEs
-s SUFFIX       Remove SUFFIX (implies -a)
bash

bash [-il] [-|+Cabefmnuvx] [-|+o OPT]... [-c 'SCRIPT' [ARG0 ARGS] | FILE ARGS | -s ARGS]

Unix shell interpreter

bc

bc [-sqlw] [FILE]...

Arbitrary precision calculator

-q      Quiet
-l      Load standard library
-s      Be POSIX compatible
-w      Warn if extensions are used

$BC_LINE_LENGTH changes output width

bunzip2

bunzip2 [-cfk] [FILE]...

Decompress FILEs (or stdin)

-c      Write to stdout
-f      Force
-k      Keep input files
-t      Test integrity
bzcat

bzcat [FILE]...

Decompress to stdout

bzip2

bzip2 [-cfkdt123456789] [FILE]...

Compress FILEs (or stdin) with bzip2 algorithm

-1..9   Compression level
-d      Decompress
-c      Write to stdout
-f      Force
-k      Keep input files
-t      Test integrity
cal

cal [-jmy] [[MONTH] YEAR]

Display a calendar

-j      Use julian dates
-m      Week starts on Monday
-y      Display the entire year
cat

cat [-nbvteA] [FILE]...

Print FILEs to stdout

-n      Number output lines
-b      Number nonempty lines
-v      Show nonprinting characters as ^x or M-x
-t      ...and tabs as ^I
-e      ...and end lines with $
-A      Same as -vte
chattr

chattr [-R] [-+rhsatn] FILE...

Change file attributes

-R      Recurse
-,+     Remove/add attributes
r       Read only
h       Hidden
s       System
a       Archive
t       Temporary
n       Not indexed
chmod

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

MODE is octal number (bit pattern sstrwxrwxrwx) or [ugoa]{+|-|=}[rwxXst]

-R      Recurse
-c      List changed files
-v      Verbose
-f      Hide errors
cksum

cksum FILE...

Calculate CRC32 checksum of FILEs

clear

clear

Clear screen

cmp

cmp [-ls] [-n NUM] 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
-n NUM  Compare at most NUM bytes
comm

comm [-123] FILE1 FILE2

Compare FILE1 with FILE2

-1      Suppress lines unique to FILE1
-2      Suppress lines unique to FILE2
-3      Suppress lines common to both files
cp

cp [-arPLHpfinlsTu] SOURCE DEST or: cp [-arPLHpfinlsu] SOURCE... { -t DIRECTORY | DIRECTORY }

Copy SOURCEs 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
-n      Don't overwrite
-l,-s   Create (sym)links
-T      Refuse to copy if DEST is a directory
-t DIR  Copy all SOURCEs into DIR
-u      Copy only newer files
cpio

cpio [-dmvu] [-F FILE] [-R USER[:GRP]] [-H newc] [-tio] [EXTR_FILE]...

Extract (-i) or list (-t) files from a cpio archive, or take file list from stdin and create an archive (-o)

Main operation mode:

        -t      List
        -i      Extract EXTR_FILEs (or all)
        -o      Create (requires -H newc)
Options:

        -H newc Archive format
        -d      Make leading directories
        -m      Restore mtime
        -v      Verbose
        -u      Overwrite
        -F FILE Input (-t,-i,-p) or output (-o) file
        -R USER[:GRP]   Set owner of created files
        -L      Dereference symlinks
        -0      NUL terminated input
        --ignore-devno
        --renumber-inodes
crc32

crc32 FILE...

Calculate CRC32 checksum of FILEs

cut

cut [OPTIONS] [FILE]...

Print selected fields from FILEs to stdout

-b LIST Output only bytes from LIST
-c LIST Output only characters from LIST
-d SEP  Field delimiter for input (default -f TAB, -F run of whitespace)
-O SEP  Field delimeter for output (default = -d for -f, one space for -F)
-D      Don't sort/collate sections or match -fF lines without delimeter
-f LIST Print only these fields (-d is single char)
-F LIST Print only these fields (-d is regex)
-s      Output only lines containing delimiter
-n      Ignored
date

date [OPTIONS] [+FMT] [[-s] TIME]

Display time (using +FMT), or set time

-u              Work in UTC (don't convert to local time)
-d TIME         Display TIME, not 'now'
-D FMT          FMT (strptime format) for -s/-d TIME conversion
-r FILE         Display last modification time of FILE
-R              Output RFC-2822 date
-I[SPEC]        Output ISO-8601 date
                SPEC=date (default), hours, minutes, seconds or ns

Recognized TIME formats:

@seconds_since_1970
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 [-x] [-eSCRIPT]... [-fFILE]... [FILE]...

Tiny RPN calculator. Operations: Arithmetic: + - * / % ^ ~ - divide with remainder | - modular exponentiation v - square root p - print top of the stack without popping f - print entire stack k - pop the value and set precision i - pop the value and set input radix o - pop the value and set output radix Examples: dc -e'2 2 + p' -> 4, dc -e'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] [iflag=skip_bytes|count_bytes|fullblock|direct] [oflag=seek_bytes|append|direct]

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
conv=swab       Swap every pair of bytes
iflag=skip_bytes        skip=N is in bytes
iflag=count_bytes       count=N is in bytes
oflag=seek_bytes        seek=N is in bytes
iflag=direct    O_DIRECT input
oflag=direct    O_DIRECT output
iflag=fullblock Read full blocks
oflag=append    Open output in append mode
status=noxfer   Suppress rate output
status=none     Suppress all output

if=/dev/zero and if=/dev/urandom are supported N may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G

df

df [-PkmhT] [-t TYPE] [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)
-T      Print filesystem type
-t TYPE Print only mounts of this type
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

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 [DIR]

Perform actions on Debian packages (.deb)

-c      List files
-f      Print control fields
-e      Extract control files to DIR (default: ./DEBIAN)
-x      Extract files to DIR (no default)
-X      Verbose extract
du

du [-aHLdclsxhmk] [FILE]...

Summarize disk space used for FILEs (or directories)

-a      Show file sizes too
-b      Apparent size (including holes)
-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)
echo

echo [-neE] [ARG]...

Print ARGs to stdout

-n      No trailing newline
-e      Interpret backslash escapes (\t=tab etc)
-E      Don't interpret backslash escapes (default)
ed

ed [-p PROMPT] [-s] [FILE]

env

env [-i0] [-u NAME]... [-] [NAME=VALUE]... [PROG ARGS]

Print current environment or run PROG after setting up environment

-, -i   Start with empty environment
-0      NUL terminated output
-u NAME Remove variable from environment
expand

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

Convert tabs to spaces, writing to stdout

-i      Don't convert tabs after non blanks
-t      Tabstops every N chars
expr

expr EXPRESSION

Print the value of EXPRESSION

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 LEN   Substring of STRING, POS counts 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.

factor

factor [NUMBER]...

Print prime factors

find

find [-HL] [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'

-L,-follow      Follow symlinks
-H              ...on command line only
-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,s,p)
        -executable     File is executable
        -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
        -atime DAYS     atime +N/-N/N days in the past
        -ctime DAYS     ctime +N/-N/N days in the past
        -mmin MINS      mtime is greater than (+N), less than (-N),
                        or exactly N minutes in the past
        -amin MINS      atime +N/-N/N minutes in the past
        -cmin MINS      ctime +N/-N/N minutes in the past
        -newer FILE     mtime is more recent than FILE's
        -inum N         File has inode number N
        -samefile FILE  File is same as FILE
        -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
        -empty          Match empty file/directory
        -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
        -exec CMD ARG + Run CMD with {} replaced by list of file names
        -delete         Delete current file/directory. Turns on -depth option
        -quit           Exit
fold

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

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

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

free [-bkmgh]

Display free and used memory

fsync

fsync [-d] FILE...

Write all buffered blocks in FILEs to disk

-d      Avoid syncing metadata
ftpget

ftpget [OPTIONS] HOST [LOCAL_FILE] REMOTE_FILE

Download a file via FTP

-c      Continue previous transfer
-v      Verbose
-u USER Username
-p PASS Password
-P PORT
ftpput

ftpput [OPTIONS] HOST [REMOTE_FILE] LOCAL_FILE

Upload a file to a FTP server

-v      Verbose
-u USER Username
-p PASS Password
-P PORT
getopt

getopt [OPTIONS] [--] OPTSTRING PARAMS

-a              Allow long options starting with single -
-l LOPT[,...]   Long options to recognize
-n PROGNAME     The name under which errors are reported
-o OPTSTRING    Short options to recognize
-q              No error messages on unrecognized options
-Q              No normal output
-s SHELL        Set shell quoting conventions
-T              Version test (exits with 4)
-u              Don't quote 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

grep

grep [-HhnlLoqvsrRiwFE] [-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
-R      Recurse and dereference symlinks
-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
-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 groups USER is in

gunzip

gunzip [-cfkt] [FILE]...

Decompress FILEs (or stdin)

-c      Write to stdout
-f      Force
-k      Keep input files
-t      Test integrity
gzip

gzip [-cfkdt123456789] [FILE]...

Compress FILEs (or stdin)

-1..9   Compression level
-d      Decompress
-c      Write to stdout
-f      Force
-k      Keep input files
-t      Test integrity
hd

hd FILE...

hd is an alias for hexdump -C

head [OPTIONS] [FILE]...

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

-n N[bkm]       Print first N lines
-n -N[bkm]      Print all except N last lines
-c [-]N[bkm]    Print first N bytes
                (b:*512 k:*1024 m:*1024^2)
-q              Never print headers
-v              Always print headers
hexdump

hexdump [-bcdoxCv] [-e FMT] [-f FMT_FILE] [-n LEN] [-s OFS] [FILE]...

Display FILEs (or stdin) in a user specified format

-b              1-byte octal display
-c              1-byte character display
-d              2-byte decimal display
-o              2-byte octal display
-x              2-byte hex display
-C              hex+ASCII 16 bytes per line
-v              Show all (no dup folding)
-e FORMAT_STR   Example: '16/1 "%02x|""\n"'
-f FORMAT_FILE
-n LENGTH       Show only first LENGTH bytes
-s OFFSET       Skip OFFSET bytes
httpd

httpd [-fv[v]] [-c CONFFILE] [-p [IP:]PORT] [-r REALM] [-h HOME] or httpd -d/-e STRING

Listen for incoming HTTP requests

-f              Run in foreground
-v[v]           Verbose
-p [IP:]PORT    Bind to IP:PORT (default *:80)
-r REALM        Authentication Realm for Basic Authentication
-h HOME         Home directory (default .)
-c FILE         Configuration file (default {/etc,HOME}/httpd.conf)
-e STRING       HTML encode STRING
-d STRING       URL decode STRING
iconv

iconv [-lc] [-o outfile] [-f from-enc] [-t to-enc] [FILE]...

Convert text between character encodings

-l  List all known character encodings
-c  Silently discard characters that cannot be converted
-o  Use outfile for output
-f  Use from-enc for input characters
-t  Use to-enc for output characters
id

id [-ugGnr] [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
inotifyd

inotifyd PROG FILE1[:MASK]...

Run PROG on filesystem changes. When a filesystem event matching MASK occurs on FILEn, PROG ACTUAL_EVENTS FILEn [SUBFILE] is run. If PROG is -, events are sent to stdout. Events:

c       File is modified
x       File can't be watched anymore
y       Subfile is moved into dir
m       Subfile is moved out of dir
n       Subfile is created
d       Subfile is deleted

inotifyd waits for PROG to exit. When x event happens for all FILEs, inotifyd exits.

install

install [-cdDsp] [-o USER] [-g GRP] [-m MODE] [-t DIR] [SOURCE]... DEST

Copy files and set attributes

-c      Just copy (default)
-d      Create directories
-D      Create leading target directories
-s      Strip symbol table
-p      Preserve date
-o USER Set ownership
-g GRP  Set group ownership
-m MODE Set permissions
-t DIR  Install to DIR
ipcalc

ipcalc [-bnmphs] ADDRESS[/PREFIX] [NETMASK]

Calculate and display network settings from IP address

-b      Broadcast address
-n      Network address
-m      Default netmask for IP
-p      Prefix for IP/NETMASK
-h      Resolved host name
-s      No error messages
jn

jn DIR JUNC

Create directory junction JUNC to DIR

kill

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

Send a signal (default: TERM) to given PIDs

-l      List all signal names and numbers
killall

killall [-lq] [-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
less

less [-EFIMmNSRh~] [FILE]...

View FILE (or stdin) one screenful at a time

-E      Quit once the end of a file is reached
-F      Quit if entire file fits on first screen
-I      Ignore case in all searches
-M,-m   Display status line with line numbers
        and percentage through the file
-N      Prefix line number to each line
-S      Truncate long lines
-R      Remove color escape codes in input
-~      Suppress ~s displayed past EOF

link FILE LINK

Create hard LINK to FILE

ln

ln [-sfnbtv] [-S SUF] 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
-T      Treat LINK as a file, not DIR
-v      Verbose
logname

logname

Print the name of the current user

ls

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

List directory contents

-1      One column output
-a      Include names starting with .
-A      Like -a, but exclude . and ..
-x      List by lines
-d      List directory names, not contents
-L      Follow symlinks
-H      Follow symlinks on command line
-R      Recurse
-p      Append / to directory names
-F      Append indicator (one of */=@|) to names
-l      Long format
-i      List inode numbers
-n      List numeric UIDs and GIDs instead of names
-s      List allocated blocks
-lc     List ctime
-lu     List atime
--full-time     List full date/time
-h      Human readable sizes (1K 243M 2G)
--group-directories-first
-S      Sort by size
-X      Sort by extension
-v      Sort by version
-t      Sort by mtime
-tc     Sort by ctime
-tu     Sort by atime
-r      Reverse sort order
-w N    Format N columns wide
--color[={always,never,auto}]
lsattr

lsattr [-Radl] [FILE]...

List file attributes

-R      Recurse
-a      Include names starting with .
-d      List directory names, not contents
-l      List long flag names

Attributes:

j       Junction
l       Symbolic link
R       Reparse point
o       Offline
e       Encrypted
c       Compressed
S       Sparse
r       Read only
h       Hidden
s       System
a       Archive
t       Temporary
n       Not indexed
lzcat

lzcat [FILE]...

Decompress to stdout

lzma

lzma -d [-cfk] [FILE]...

Decompress FILEs (or stdin)

-d      Decompress
-c      Write to stdout
-f      Force
-k      Keep input files
-t      Test integrity
lzop

lzop [-cfUvd123456789CF] [FILE]...

-1..9   Compression level
-d      Decompress
-c      Write to stdout
-f      Force
-U      Delete input files
-v      Verbose
-F      Don't store or verify checksum
-C      Also write checksum of compressed block
lzopcat

lzopcat [-vF] [FILE]...

-v      Verbose
-F      Don't verify checksum
man

man [-aw] [SECTION] MANPAGE[.SECTION]...

Display manual page

-a      Display all pages
-w      Show page locations

$COLUMNS overrides output width

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
mkdir

mkdir [-m MODE] [-p] DIRECTORY...

Create DIRECTORY

-m MODE Mode
-p      No error if exists; make parent directories as needed
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
-q      Fail silently on errors
-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

mv

mv [-finT] SOURCE DEST or: mv [-fin] SOURCE... { -t DIRECTORY | DIRECTORY }

Rename SOURCE to DEST, or move SOURCEs to DIRECTORY

-f      Don't prompt before overwriting
-i      Interactive, prompt before overwrite
-n      Don't overwrite an existing file
-T      Refuse to move if DEST is a directory
-t DIR  Move all SOURCEs into DIR
nc

nc [-l] [-p PORT] [IPADDR PORT]

Open a pipe to IP:PORT

-l      Listen mode, for inbound connects
-p PORT Local port
nl

nl [OPTIONS] [FILE]...

Write FILEs to standard output with line numbers added

-b STYLE        Which lines to number - a: all, t: nonempty, n: none
-i N            Line number increment
-s STRING       Use STRING as line number separator
-v N            Start from N
-w N            Width of line numbers
nproc

nproc [--all] [--ignore=N]

Print number of available CPUs

--all           Number of installed CPUs
--ignore=N      Exclude N CPUs
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

paste

paste [-d LIST] [-s] [FILE]...

Paste lines from each input file, separated with tab

-d LIST Use delimiters from LIST, not tab
-s      Serial: one file at a time
patch

patch [-RNE] [-p N] [-i DIFF] [ORIGFILE [PATCHFILE]]

-p N    Strip N leading components from file names
-i DIFF Read DIFF instead of stdin
-R      Reverse patch
-N      Ignore already applied patches
-E      Remove output files if they become empty
--dry-run       Don't actually change files
pgrep

pgrep [-flanovx] [-s SID|-P PPID|PATTERN]

Display process(es) selected by regex PATTERN

-l      Show command name too
-a      Show command line too
-f      Match against entire command line
-n      Show the newest process only
-o      Show the oldest process only
-v      Negate the match
-x      Match whole name (not substring)
-s      Match session ID (0 for current)
-P      Match parent process ID
pidof

pidof [-s] [-o PID] [NAME]...

List PIDs of all processes with names that match NAMEs

-s      Show only one PID
-o PID  Omit given pid
        Use %PPID to omit pid of pidof's parent
pipe_progress

pipe_progress

Display a dot to indicate pipe activity

pkill

pkill [-l|-SIGNAL] [-xfvno] [-s SID|-P PPID|PATTERN]

Send signal to processes selected by regex PATTERN

-l      List all signals
-x      Match whole name (not substring)
-f      Match against entire command line
-s SID  Match session ID (0 for current)
-P PPID Match parent process ID
-v      Negate the match
-n      Signal the newest process only
-o      Signal the oldest process only
printenv

printenv [VARIABLE]...

Print environment VARIABLEs. If no VARIABLE specified, print all.

printf

printf FORMAT [ARG]...

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

ps

ps [-o COL1,COL2=HEADER]

Show list of processes

-o COL1,COL2=HEADER     Select columns for display
pwd

pwd

Print the full filename of the current working directory

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...

Print absolute pathnames of FILEs

reset

reset

Reset terminal (ESC codes) and termios (signals, buffering, echo)

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 [-p] DIRECTORY...

Remove DIRECTORY if it is empty

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

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

Manipulate RPM packages

Commands:

-i      Install package
-qp     Query package
-qpi    Show information
-qpl    List contents
-qpd    List documents
-qpc    List config files
rpm2cpio

rpm2cpio PACKAGE.rpm

Output a cpio archive of the rpm file

sed

sed [-i[SFX]] [-nrE] [-f FILE]... [-e CMD]... [FILE]... or: sed [-i[SFX]] [-nrE] CMD [FILE]...

-e CMD  Add CMD to sed commands to be executed
-f FILE Add FILE contents to sed commands to be executed
-i[SFX] Edit files in-place (otherwise write to stdout)
        Optionally back files up, appending SFX
-n      Suppress automatic printing of pattern space
-r,-E   Use extended regex syntax
-b      Keep CR/LF (Windows-only)

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
sh

sh [-il] [-|+Cabefmnuvx] [-|+o OPT]... [-c 'SCRIPT' [ARG0 ARGS] | FILE ARGS | -s 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
sha3sum

sha3sum [-c[sw]] [-a BITS] [FILE]...

Print or check SHA3 checksums

-c      Check sums against list in FILEs
-s      Don't output anything, status code shows success
-w      Warn about improperly formatted checksum lines
-a BITS 224 (default), 256, 384, 512
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
shred

shred [-fuz] [-n N] [-s SIZE] FILE...

Overwrite/delete FILEs

-f      Chmod to ensure writability
-s SIZE Size to write
-n N    Overwrite N times (default 3)
-z      Final overwrite with zeros
-u      Remove file
shuf

shuf [-n NUM] [-o FILE] [-z] [FILE | -e [ARG...] | -i L-H]

Randomly permute lines

-n NUM  Output at most NUM lines
-o FILE Write to FILE, not standard output
-z      NUL terminated output
-e      Treat ARGs as lines
-i L-H  Treat numbers L-H as 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 [-nrughMcszbdfiokt] [-o FILE] [-k START[.OFS][OPTS][,END[.OFS][OPTS]] [-t CHAR] [FILE]...

Sort lines of text

-o FILE Output to FILE
-c      Check whether input is sorted
-b      Ignore leading blanks
-f      Ignore case
-i      Ignore unprintable characters
-d      Dictionary order (blank or alphanumeric only)
-n      Sort numbers
-g      General numerical sort
-h      Sort human readable numbers (2K 1G)
-M      Sort month
-V      Sort version
-t CHAR Field separator
-k N[,M] Sort by Nth field
-r      Reverse sort order
-s      Stable (don't sort ties alphabetically)
-u      Suppress duplicate lines
-z      NUL terminated input and output
split

split [OPTIONS] [INPUT [PREFIX]]

-b N[k|m]       Split by N (kilo|mega)bytes
-l N            Split by N lines
-a N            Use N letters as suffix
ssl_client

ssl_client [-e] -h handle [-n SNI]

stat

stat [-ltf] [-c FMT] FILE...

Display file (default) or filesystem status

-c FMT  Use the specified format
-f      Display filesystem status
-L      Follow links
-t      Terse display

FMT sequences for files:

%a     Access rights in octal
%A     Access rights in human readable form
%b     Number of blocks allocated (see %B)
%B     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
%G     Group name
%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
%U     User name
%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

FMT sequences for file systems:

%a     Free blocks available to non-superuser
%b     Total data blocks
%c     Total file nodes
%d     Free file nodes
%f     Free blocks
%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 [-fo] [-t o|d|x] [-n LEN] [FILE]...

Display printable strings in a binary file

-f              Precede strings with filenames
-o              Precede strings with octal offsets
-t o|d|x        Precede strings with offsets in base 8/10/16
-n LEN          At least LEN characters form a string (default 4)
su

su [-c "CMD"]

Run shell with elevated privileges

-c CMD  Command to pass to 'sh -c'
sum

sum [-rs] [FILE]...

Checksum and count the blocks in a file

-r      Use BSD sum algorithm (1K blocks)
-s      Use System V sum algorithm (512byte blocks)
sync

sync

Write all buffered blocks to disk

tac

tac [FILE]...

Concatenate FILEs and print them in reverse

tail

tail [OPTIONS] [FILE]...

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

-c [+]N[bkm]    Print last N bytes
-n N[bkm]       Print last N lines
-n +N[bkm]      Start on Nth line and print the rest
                (b:*512 k:*1024 m:*1024^2)
-q              Never print headers
-v              Always print headers
-f              Print data as file grows
-F              Same as -f, but keep retrying
-s SECONDS      Wait SECONDS between reads with -f
tar

tar c|x|t [-ZzJjahmvokO] [-f TARFILE] [-C DIR] [-T FILE] [-X FILE] [LONGOPT]... [FILE]...

Create, extract, or list files from a tar file

c       Create
x       Extract
t       List
-f FILE Name of TARFILE ('-' for stdin/out)
-C DIR  Change to DIR before operation
-v      Verbose
-O      Extract to stdout
-m      Don't restore mtime
-o      Don't restore user:group
-k      Don't replace existing files
-Z      (De)compress using compress
-z      (De)compress using gzip
-J      (De)compress using xz
-j      (De)compress using bzip2
--lzma  (De)compress using lzma
-a      (De)compress based on extension
-h      Follow symlinks
-T FILE File with names to include
-X FILE File with glob patterns to exclude
--exclude PATTERN       Glob pattern to exclude
--overwrite             Replace existing files
--strip-components NUM  NUM of leading components to strip
--no-recursion          Don't descend in directories
--numeric-owner         Use numeric user:group
--no-same-permissions   Don't restore access permissions
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)
time

time [-pa] [-o FILE] PROG ARGS

Run PROG, display resource usage when it exits

-p      POSIX output format
-o FILE Write result to FILE
-a      Append (else overwrite)
timeout

timeout [-s SIG] [-k KILL_SECS] SECS PROG ARGS

Run PROG. Send SIG to it if it is not gone in SECS seconds. Default SIG: TERM. If it still exists in KILL_SECS seconds, send KILL.

touch

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

Update mtime of FILEs

-c      Don't create files
-h      Don't follow links
-a      Change only atime
-m      Change only mtime
-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
truncate

truncate [-c] -s SIZE FILE...

Truncate FILEs to SIZE

-c      Do not create files
-s SIZE
ts

ts [-is] [STRFTIME]

Pipe stdin to stdout, add timestamp to each line

-s      Time since start
-i      Time since previous line
tsort

tsort [FILE]

Topological sort

ttysize

ttysize [w] [h]

Print dimensions of stdin tty, or 80x24

uname

uname [-amnrspvio]

Print system information

-a      Print all
-m      Machine (hardware) type
-n      Hostname
-r      Kernel release
-s      Kernel name (default)
-p      Processor type
-v      Kernel version
-i      Hardware platform
-o      OS name
uncompress

uncompress [-cf] [FILE]...

Decompress FILEs (or stdin)

-c      Write to stdout
-f      Overwrite
unexpand

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

Convert spaces to tabs, writing to stdout

-a      Convert all blanks
-f      Convert only leading blanks
-t N    Tabstops every N chars
uniq

uniq [-cduiz] [-f,s,w N] [FILE [OUTFILE]]

Discard duplicate lines

-c      Prefix lines by the number of occurrences
-d      Only print duplicate lines
-u      Only print unique lines
-i      Ignore case
-z      NUL terminated output
-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

unlink FILE

Delete FILE by calling unlink()

unlzma

unlzma [-cfk] [FILE]...

Decompress FILEs (or stdin)

-c      Write to stdout
-f      Force
-k      Keep input files
-t      Test integrity
unlzop

unlzop [-cfUvF] [FILE]...

-c      Write to stdout
-f      Force
-U      Delete input files
-t      Test integrity
-v      Verbose
-F      Don't verify checksum
unxz

unxz [-cfk] [FILE]...

Decompress FILEs (or stdin)

-c      Write to stdout
-f      Force
-k      Keep input files
-t      Test integrity
unzip

unzip [-lnojpq] FILE[.zip] [FILE]... [-x FILE]... [-d DIR]

Extract FILEs from ZIP archive

-l      List contents (with -q for short form)
-n      Never overwrite files (default: ask)
-o      Overwrite
-j      Do not restore paths
-p      Write to stdout
-t      Test
-q      Quiet
-x FILE Exclude FILEs
-d DIR  Extract 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
vi

vi [-c CMD] [-R] [-H] [FILE]...

Edit FILE

-c CMD  Initial command to run ($EXINIT and ~/.exrc also available)
-R      Read-only
-H      List available features
watch

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

Run PROG periodically

-n SEC  Period (default 2)
-t      Don't print header
wc

wc [-clwL] [FILE]...

Count lines, words, and bytes for FILEs (or stdin)

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

wget [-cqS] [--spider] [-O FILE] [-o LOGFILE] [--header STR] [--post-data STR | --post-file FILE] [-Y on/off] [-P DIR] [-U AGENT] URL...

Retrieve files via HTTP or FTP

--spider        Only check URL existence: $? is 0 if exists
--header STR    Add STR (of form 'header: value') to headers
--post-data STR Send STR using POST method
--post-file FILE        Send FILE using POST method
-c              Continue retrieval of aborted transfer
-q              Quiet
-P DIR          Save to DIR (default .)
-S              Show server response
-O FILE         Save to FILE ('-' for stdout)
-o LOGFILE      Log messages to FILE
-U STR          Use STR for User-Agent header
-Y on/off       Use proxy
which

which [-a] COMMAND...

Locate COMMAND

-a      Show all matches
whoami

whoami

Print the user name associated with the current effective user id

whois

whois [-i] [-h SERVER] [-p PORT] NAME...

Query WHOIS info about NAME

-i      Show redirect results too
-h,-p   Server to query
xargs

xargs [OPTIONS] [PROG ARGS]

Run PROG on every item given by stdin

-0      NUL terminated input
-a FILE Read from FILE instead of stdin
-r      Don't run command if input is empty
-t      Print the command on stderr before execution
-p      Ask user whether to run each command
-E STR,-e[STR]  STR stops input processing
-I STR  Replace STR within PROG ARGS with input line
-n N    Pass no more than N args to PROG
-s N    Pass command line of no more than N bytes
-P N    Run up to N PROGs in parallel
-x      Exit if size is exceeded
xxd

xxd [-pri] [-g N] [-c N] [-n LEN] [-s OFS] [-o OFS] [FILE]

Hex dump FILE (or stdin)

-g N            Bytes per group
-c N            Bytes per line
-p              Show only hex bytes, assumes -c30
-i              C include file style
-l LENGTH       Show only first LENGTH bytes
-s OFFSET       Skip OFFSET bytes
-o OFFSET       Add OFFSET to displayed offset
-r              Reverse (with -p, assumes no offsets in input)
xz

xz -d [-cfk] [FILE]...

Decompress FILEs (or stdin)

-d      Decompress
-c      Write to stdout
-f      Force
-k      Keep input files
-t      Test integrity
xzcat

xzcat [FILE]...

Decompress to stdout

yes

yes [STRING]

Repeatedly print a line with STRING, or 'y'

zcat

zcat [FILE]...

Decompress to stdout