--- name: "udhcpc" section: "8" platform: "linux" package: "udhcpc" version: "1:1.37.0-6" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/busybox" --- # udhcpc(8) The Swiss Army Knife of Embedded Linux Part of [busybox(1)](/busybox/1.md). ## NAME BusyBox - The Swiss Army Knife of Embedded Linux ## SYNTAX ``` busybox [arguments...] # or [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. 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. ## 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: ``` [, [[, acpid, adjtimex, ar, arch, arp, arping, ascii, ash, awk, base64, basename, bc, blkdiscard, blkid, blockdev, brctl, bunzip2, bzcat, bzip2, cal, cat, chgrp, chmod, chown, chroot, chvt, clear, cmp, cp, cpio, crc32, crond, crontab, cttyhack, cut, date, dc, dd, deallocvt, depmod, devmem, df, diff, dirname, dmesg, dnsdomainname, dos2unix, dpkg, dpkg-deb, du, dumpkmap, dumpleases, echo, ed, egrep, env, expand, expr, factor, fallocate, false, fatattr, fdisk, fgrep, find, findfs, fold, free, freeramdisk, fsfreeze, fstrim, ftpget, ftpput, getfattr, getopt, getty, grep, groups, gunzip, gzip, halt, head, hexdump, hostid, hostname, httpd, hwclock, i2cdetect, i2cdump, i2cget, i2cset, i2ctransfer, id, ifconfig, ifdown, ifup, init, insmod, install, ionice, ip, ipcalc, kill, killall, klogd, last, less, link, linux32, linux64, linuxrc, ln, loadfont, loadkmap, logger, login, logname, logread, losetup, ls, lsmod, lsscsi, lzcat, lzma, lzop, md5sum, mdev, microcom, mim, mkdir, mkdosfs, mke2fs, mkfifo, mknod, mkpasswd, mkswap, mktemp, modinfo, modprobe, more, mount, mt, mv, nameif, nbd-client, nc, netstat, nl, nologin, nproc, nsenter, nslookup, nuke, od, openvt, partprobe, passwd, paste, patch, pidof, ping, ping6, pivot_root, poweroff, printf, ps, pwd, rdate, readlink, realpath, reboot, renice, reset, resume, rev, rm, rmdir, rmmod, route, rpm, rpm2cpio, run-init, run-parts, sed, seq, setkeycodes, setpriv, setsid, sh, sha1sum, sha256sum, sha3sum, sha512sum, shred, shuf, sleep, sort, ssl_client, start-stop-daemon, stat, strings, stty, su, sulogin, svc, svok, swapoff, swapon, switch_root, sync, sysctl, syslogd, tac, tail, tar, taskset, tc, tee, telnet, test, tftp, time, timeout, top, touch, tr, traceroute, traceroute6, true, truncate, ts, tty, tunctl, ubirename, udhcpc, udhcpc6, udhcpd, uevent, umount, uname, uncompress, unexpand, uniq, unix2dos, unlink, unlzma, unshare, unxz, unzip, uptime, usleep, uudecode, uuencode, vconfig, vi, w, watch, watchdog, wc, wget, which, who, whoami, xargs, xxd, xz, xzcat, yes, zcat ``` ## COMMAND DESCRIPTIONS - **acpid** acpid \[-df\] \[-c CONFDIR\] \[-l LOGFILE\] \[-a ACTIONFILE\] \[-M MAPFILE\] \[-e PROC\_EVENT\_FILE\] \[-p PIDFILE\] Listen to ACPI events and spawn specific helpers on event arrival ``` -d Log to stderr, not log file (implies -f) -f Run in foreground -c DIR Config directory [/etc/acpi] -e FILE /proc event file [/proc/acpi/event] -l FILE Log file [/var/log/acpid.log] -p FILE Pid file [/var/run/acpid.pid] -a FILE Action file [/etc/acpid.conf] -M FILE Map file [/etc/acpi.map] ``` Accept and ignore compatibility options -g -m -s -S -v - **adjtimex** adjtimex \[-q\] \[-o OFS\] \[-f FREQ\] \[-p TCONST\] \[-t TICK\] Read or set kernel time variables. See [**adjtimex**(2)](/adjtimex/2.md) ``` -q Quiet -o OFF Time offset, microseconds -f FREQ Frequency adjust, integer kernel units (65536 is 1ppm) -t TICK Microseconds per tick, usually 10000 (positive -t or -f values make clock run faster) -p TCONST ``` - **ar** ar x\|p\|t \[-ov\] ARCHIVE \[FILE\]... Extract or list FILEs from an ar archive ``` x Extract p Extract to stdout t List -o Restore mtime -v Verbose ``` - **arch** arch Print system architecture - **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 -d Delete ARP entry -s Set new entry -v Verbose -n Don't resolve names -i IF Network interface -D Read HWADDR from IFACE -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 Exit with 1 if DST_IP replies -U Unsolicited ARP mode, update your neighbors -A ARP answer mode, update your neighbors -c N Stop after sending N ARP requests -w TIMEOUT Seconds to wait for ARP reply -I IFACE Interface to use (default eth0) -s SRC_IP Sender IP address DST_IP Target IP address ``` - **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/-E FILE Read program from FILE -e AWK_PROGRAM ``` - **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) ``` - **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 - **blkdiscard** blkdiscard \[-o OFS\] \[-l LEN\] \[-s\] DEVICE Discard sectors on DEVICE ``` -o OFS Byte offset into device -l LEN Number of bytes to discard -s Perform a secure discard ``` - **blkid** blkid \[BLOCKDEV\]... Print UUIDs of all filesystems - **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 --getra Get readahead in 512-byte sectors --setra SECTORS Set readahead --flushbufs Flush buffers --rereadpt Reread partition table ``` - **brctl** brctl COMMAND \[BRIDGE \[ARGS\]\] 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 \[-cfk\] \[FILE\]... 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 ``` - **chgrp** chgrp \[-RhLHPcvf\]... GROUP FILE... Change the group membership of FILEs to GROUP ``` -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) -R Recurse -c List changed files -v Verbose -f Hide errors ``` - **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 ``` - **chown** chown \[-RhLHPcvf\]... USER\[:\[GRP\]\] FILE... Change the owner and/or group of FILEs to USER and/or GRP ``` -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) -R Recurse -c List changed files -v Verbose -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 \[-ls\] \[-n NUM\] 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 ``` - **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 on stdin, 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 - **crond** crond \[-fbS\] \[-l N\] \[-L LOGFILE\] \[-c DIR\] ``` -f Foreground -b Background (default) -S Log to syslog (default) -l N Set log level. Most verbose 0, default 8 -L FILE Log to FILE -c DIR Cron dir. Default:/var/spool/cron/crontabs ``` - **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 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 delimiter for output (default = -d for -f, one space for -F) -D Don't sort/collate sections or match -fF lines without delimiter -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) [-s] TIME Set time to 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 ``` N may be suffixed by c (1), w (2), b (512), kB (1000), k (1024), MB, M, GB, G - **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 ``` - **devmem** devmem ADDRESS \[WIDTH \[VALUE\]\] Read/write from physical address ``` ADDRESS Address to act upon WIDTH Width (8/16/...) VALUE Data to be written ``` - **df** df \[-PkmhTai\] \[-B SIZE\] \[-t TYPE\] \[FILESYSTEM\]... 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 -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 \[-cr\] \[-n LEVEL\] \[-s SIZE\] Print or control the kernel ring buffer ``` -c Clear ring buffer after printing -n LEVEL Set console logging level -s SIZE Buffer size -r Print raw message buffer ``` - **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) ``` - **dumpkmap** dumpkmap \> keymap Print a binary keyboard translation table to stdout - **dumpleases** dumpleases \[-r\|-a\] \[-d\] \[-f LEASEFILE\] Display DHCP leases granted by udhcpd ``` -f FILE Lease file -r Show remaining time -a Show expiration time -d Show time in seconds ``` - **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 - **fallocate** fallocate \[-o OFS\] -l LEN FILE Preallocate space for FILE ``` -o OFS Offset of range -l LEN Length of range ``` - **fatattr** fatattr \[-+rhsvda\] FILE... Change file attributes on FAT filesystem ``` - Clear attributes + Set attributes r Read only h Hidden s System v Volume label d Directory a Archive ``` - **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 Typically 255 -S SECTORS Typically 63 ``` - **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 -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 -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 -ok CMD ARG ; Prompt and run CMD with {} replaced -quit Exit ``` - **findfs** findfs LABEL=label or UUID=uuid Find a filesystem device based on a label or UUID - **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 - **freeramdisk** freeramdisk DEVICE Free all memory used by the specified ramdisk - **fsfreeze** fsfreeze --\[un\]freeze MOUNTPOINT Flush and halt writes to MOUNTPOINT - **fstrim** fstrim \[OPTIONS\] MOUNTPOINT ``` -o OFFSET Offset in bytes to discard from -l LEN Bytes to discard -m MIN Minimum extent length -v Print number of discarded bytes ``` - **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 ``` - **getfattr** getfattr \[-h\] {-d\|-n ATTR} FILE... Get extended attributes ``` -h Do not follow symlinks -d Dump all attributes -n ATTR Get attribute ATTR ``` - **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 - **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 \[-HhnlLoqvsrRiwFEz\] \[-m N\] \[-A\|B\|C N\] { 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 -z NUL terminated input -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 \[-cfkdt\] \[FILE\]... Compress FILEs (or stdin) ``` -d Decompress -c Write to stdout -f Force -k Keep input files -t Test integrity ``` - **halt** halt \[-d DELAY\] \[-nfw\] 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 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 ``` - **hostid** hostid Print out a unique 32-bit identifier for the machine - **hostname** hostname \[-sidf\] \[HOSTNAME \| -F FILE\] Show 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 Run in foreground -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 \[-ul\] \[-f DEV\] \[-s\|-w\|--systz\|--param-get PARAM\|--param-set PARAM=VAL\] Show or set hardware clock (RTC) ``` -f DEV Use this device (e.g. /dev/rtc2) -u Assume RTC is kept in UTC -l Assume RTC is kept in local time (if neither is given, read from /etc/adjtime) -s Set system time from RTC -w Set RTC from system time --systz Set in-kernel timezone, correct system time if RTC is kept in local time --param-get PARAM Get RTC parameter --param-set PARAM=VAL Set RTC parameter ``` - **i2cdetect** i2cdetect -l \| -F I2CBUS \| \[-ya\] \[-q\|-r\] I2CBUS \[FIRST LAST\] Detect I2C chips ``` -l List installed buses -F BUS# List functionalities on this bus -y Disable interactive mode -a Force scanning of non-regular addresses -q Use smbus quick write commands for probing (default) -r Use smbus read byte commands for probing FIRST and LAST limit probing range ``` - **i2cdump** i2cdump \[-fy\] \[-r FIRST-LAST\] BUS ADDR \[MODE\] Examine I2C registers ``` I2CBUS I2C bus number ADDRESS 0x03-0x77 MODE is: b Byte (default) w Word W Word on even register addresses i I2C block s SMBus block c Consecutive byte Append p for SMBus PEC -f Force access -y Disable interactive mode -r Limit the number of registers being accessed ``` - **i2cget** i2cget \[-fy\] BUS CHIP-ADDRESS \[DATA-ADDRESS \[MODE\]\] Read from I2C/SMBus chip registers ``` I2CBUS I2C bus number ADDRESS 0x03-0x77 MODE is: b Read byte data (default) w Read word data c Write byte/read byte Append p for SMBus PEC -f Force access -y Disable interactive mode ``` - **i2cset** i2cset \[-fy\] \[-m MASK\] BUS CHIP-ADDRESS DATA-ADDRESS \[VALUE\] ... \[MODE\] Set I2C registers ``` I2CBUS I2C bus number ADDRESS 0x03-0x77 MODE is: c Byte, no value b Byte data (default) w Word data i I2C block data s SMBus block data Append p for SMBus PEC -f Force access -y Disable interactive mode -r Read back and compare the result -m MASK Mask specifying which bits to write ``` - **i2ctransfer** i2ctransfer \[-fay\] I2CBUS { rLENGTH\[@ADDR\] \| wLENGTH\[@ADDR\] DATA...}... Read/write I2C data in one transfer ``` -f Force access to busy addresses -a Force access to non-regular addresses -y Disable interactive mode ``` - **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 ``` - **ifconfig** ifconfig \[-a\] \[IFACE\] \[ADDRESS\] 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 \[-nmvf\] \[-i FILE\] -a \| IFACE... ``` -a Deconfigure all interfaces -i FILE Use FILE instead of /etc/network/interfaces -n Dry run (note: doesn't disable mappings) -m Don't run any mappings -v Print out what would happen before doing it -f Force ``` - **ifup** ifup \[-nmvf\] \[-i FILE\] -a \| IFACE... ``` -a Configure all interfaces -i FILE Use FILE instead of /etc/network/interfaces -n Dry run (note: doesn't disable mappings) -m Don't run any mappings -v Print out what would happen before doing it -f Force ``` - **init** init Init is the first process started during boot. It never exits. It (re)spawns children according to /etc/inittab. Signals: HUP: reload /etc/inittab TSTP: stop respawning until CONT QUIT: re-exec another init USR1/TERM/USR2/INT: run halt/reboot/poweroff/Ctrl-Alt-Del script - **insmod** insmod FILE \[SYMBOL=VALUE\]... Load kernel module - **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 ``` - **ionice** ionice \[-c 1-3\] \[-n 0-7\] \[-t\] { -p PID \| PROG ARGS } Change I/O priority and class ``` -c N Class. 1:realtime 2:best-effort 3:idle -n N Priority -t Ignore errors ``` - **ip** ip \[OPTIONS\] address\|route\|link\|tunnel\|neigh\|rule \[ARGS\] OPTIONS := -f\[amily\] inet\|inet6\|link \| -o\[neline\] ip addr add\|del IFADDR dev IFACE \| show\|flush \[dev IFACE\] \[to PREFIX\] ip route list\|flush\|add\|del\|change\|append\|replace\|test ROUTE ip link set IFACE \[up\|down\] \[arp on\|off\] \[multicast on\|off\]\ \[promisc on\|off\] \[mtu NUM\] \[name NAME\] \[qlen NUM\] \[address MAC\]\ \[master IFACE \| nomaster\] \[netns PID\] \[type TYPE ARGS\] ip tunnel add\|change\|del\|show \[NAME\]\ \[mode ipip\|gre\|sit\] \[remote ADDR\] \[local ADDR\] \[ttl TTL\] ip neigh show\|flush \[to PREFIX\] \[dev DEV\] \[nud STATE\] ip rule \[list\] \| add\|del SELECTOR ACTION - **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 ``` - **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 ``` - **klogd** klogd \[-c N\] \[-n\] Log kernel messages to syslog ``` -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 \[-EFIMmNSRh~\] \[FILE\]... 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** 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 ``` - **loadfont** loadfont \< font Load a console font from stdin - **loadkmap** loadkmap \< keymap Load a binary keyboard translation table from stdin - **logger** logger \[-s\] \[-t TAG\] \[-p PRIO\] \[MESSAGE\] 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 (number 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 HOST Host user came from (for network logins) -p Preserve environment ``` `$LOGIN_TIMEOUT` Seconds (default 60, 0 - disable) - **logname** logname Print the name of the current user - **logread** logread \[-fF\] Show messages in syslogd's circular buffer ``` -f Output data as log grows -F Same as -f, but dump buffer first ``` - **losetup** losetup \[-rP\] \[-o OFS\] {-f\|LOOPDEV} FILE: associate loop devices\ losetup -c LOOPDEV: reread file size\ losetup -d LOOPDEV: disassociate\ losetup -a: show status\ losetup -f: show next free loop device ``` -o OFS Start OFS bytes into FILE -P Scan for partitions -r Read-only -f Show/use next free loop device ``` - **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}] ``` - **lsmod** lsmod List loaded kernel modules - **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 ``` - **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 \[-vS\] { \[-s\] \| \[-df\] } ``` -v Verbose -S Log to syslog too -s Scan /sys and populate /dev -d Daemon, listen on netlink -f Run in foreground ``` Bare mdev is a kernel hotplug helper. To activate it:\ echo /sbin/mdev \>/proc/sys/kernel/hotplug It uses /etc/mdev.conf with lines\ \[-\]\[ENV=regex;\]...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. If /dev/mdev.log file exists, debug log will be appended to it. - **microcom** microcom \[-d DELAY\_MS\] \[-t TIMEOUT\_MS \] \[-s SPEED\] \[-X\] TTY Copy bytes from stdin to TTY and from TTY to stdout ``` -d DELAY Wait up to DELAY ms for TTY output before sending every next byte to it -t TIMEOUT Exit if both stdin and TTY are silent for TIMEOUT ms -s SPEED Set serial line to SPEED -X Disable special meaning of NUL and Ctrl-X from stdin ``` - **mim** mim \[-f FILE\] \[SHELL\_OPTIONS\] \[TARGET\] ... Run a script from a Makefile-like specification file ``` -f FILE Spec file (default Mimfile) ``` - **mkdir** mkdir \[-m MODE\] \[-p\] DIRECTORY... Create DIRECTORY ``` -m MODE Mode -p No error if exists; make parent directories as needed ``` - **mkdosfs** mkdosfs \[-v\] \[-n LABEL\] BLOCKDEV \[KBYTES\] Make a FAT32 filesystem ``` -v Verbose -n LBL Volume label ``` - **mke2fs** mke2fs \[-Fn\] \[-b BLK\_SIZE\] \[-i INODE\_RATIO\] \[-I INODE\_SIZE\] \[-m RESERVED\_PERCENT\] \[-L LABEL\] BLOCKDEV \[KBYTES\] ``` -b BLK_SIZE Block size, bytes -F Force -i RATIO Max number of files is filesystem_size / RATIO -I BYTES Inode size (min 128) -L LBL Volume label -m PERCENT Percent of blocks to reserve for admin -n Dry run ``` - **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 MINOR must be omitted) ``` - **mkpasswd** mkpasswd \[-P FD\] \[-m TYPE\] \[-S SALT\] \[PASSWORD\] \[SALT\] Print [**crypt**(3)](/crypt/3.md) hashed PASSWORD ``` -P N Read password from fd N -m TYPE des,md5,sha256/512 (default ) -S SALT ``` - **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 -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 - **modinfo** modinfo \[-adlpn0\] \[-F keyword\] 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 NUL terminated output ``` - **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 \[OPTIONS\] \[-o OPT\] 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 -t FSTYPE[,...] Filesystem type(s) -T FILE Read FILE instead of /etc/fstab -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 Same as -r ``` There are filesystem-specific -o flags. - **mt** mt \[-f DEVICE\] OPCODE VALUE Control magnetic tape drive operation 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 \[-finT\] 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 ``` - **nameif** nameif \[-s\] \[-c FILE\] \[IFNAME HWADDR\]... Rename network interface while it in the down state. The device with address HWADDR is renamed to IFNAME. ``` -c FILE Configuration file (default: /etc/mactab) -s Log to syslog ``` - **nbd-client** nbd-client { \[-b BLKSIZE\] \[-N NAME\] \[-t SEC\] \[-p\] HOST \[PORT\] \| -d } BLOCKDEV Connect to HOST and provide network block device on BLOCKDEV - **nc** nc \[-iN\] \[-wN\] \[-l\] \[-p PORT\] \[-f FILE\|IPADDR PORT\] \[-e PROG\] Open a pipe to IP:PORT or FILE ``` -l Listen mode, for inbound connects (use -ll with -e for persistent server) -p PORT Local port -w SEC Connect timeout -i SEC Delay interval for lines sent -f FILE Use file (ala /dev/ttyS0) instead of network -e PROG Run PROG after connect ``` - **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 ``` - **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 ``` - **nologin** nologin Politely refuse a login - **nproc** nproc \[--all\] \[--ignore=N\] Print number of available CPUs ``` --all Number of installed CPUs --ignore=N Exclude N CPUs ``` - **nsenter** nsenter \[OPTIONS\] \[PROG ARGS\] ``` -t PID Target process to get namespaces from -m[FILE] Enter mount namespace -u[FILE] Enter UTS namespace (hostname etc) -i[FILE] Enter System V IPC namespace -n[FILE] Enter network namespace -p[FILE] Enter pid namespace -U[FILE] Enter user namespace -S UID Set uid in entered namespace -G GID Set gid in entered namespace --preserve-credentials Don't touch uids or gids -r[DIR] Set root directory -w[DIR] Set working directory -F Don't fork before exec'ing PROG ``` - **nslookup** nslookup \[-type=QUERY\_TYPE\] \[-debug\] HOST \[DNS\_SERVER\] Query DNS about HOST QUERY\_TYPE: soa,ns,a,aaaa,cname,mx,txt,ptr,srv,any - **nuke** nuke DIR... Remove DIRs - **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 ``` - **partprobe** partprobe DEVICE... Ask kernel to rescan partition table - **passwd** passwd \[-a ALG\] \[-dlu\] \[USER\] Change USER's password (default: current user) ``` -a ALG des,md5,sha256/512 (default ) -d Set password to '' -l Lock (disable) account -u Unlock (enable) account ``` - **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 ``` - **pidof** pidof \[NAME\]... List PIDs of all processes with names that match NAMEs - **ping** ping \[OPTIONS\] HOST Send ICMP ECHO\_REQUESTs to HOST ``` -4,-6 Force IP or IPv6 name resolution -c CNT Send only CNT pings -s SIZE Send SIZE data bytes in packets (default 56) -i SECS Interval -A Ping as soon as reply is received -t TTL Set TTL -I IFACE/IP Source interface or IP address -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 display output at start/finish -p HEXBYTE Payload pattern ``` - **ping6** ping6 \[OPTIONS\] HOST Send ICMP ECHO\_REQUESTs to HOST ``` -c CNT Send only CNT pings -s SIZE Send SIZE data bytes in packets (default 56) -i SECS Interval -A Ping as soon as reply is received -I IFACE/IP Source interface or IP address -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 display output at start/finish -p HEXBYTE Payload pattern ``` - **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 \[-d DELAY\] \[-nf\] 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 \[-s/-p\] HOST Set and print time from HOST using RFC 868 ``` -s Only set system time -p Only print time ``` - **readlink** readlink \[-fnv\] FILE Display the value of a symlink ``` -n Don't add newline -f Canonicalize by following all symlinks -v Verbose ``` - **realpath** realpath FILE... Print absolute pathnames of FILEs - **reboot** reboot \[-d DELAY\] \[-nf\] Reboot the system ``` -d SEC Delay interval -n Do not sync -f Force (don't go through init) ``` - **renice** renice \[-n\] PRIORITY \[\[-p\|g\|u\] ID...\]... Change scheduling priority of a running process ``` -n Add PRIORITY to current nice value Without -n, nice value is set to PRIORITY -p Process ids (default) -g Process group ids -u Process user names ``` - **reset** reset Reset terminal (ESC codes) and termios (signals, buffering, echo) - **resume** resume BLOCKDEV \[OFFSET\] Restore system state from 'suspend-to-disk' data in BLOCKDEV - **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 ``` - **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 \[-ne\] \[-A inet\[6\]\] \[{add\|del} \[-net\|-host\] TARGET \[netmask MASK\]\ \[gw GATEWAY\] \[metric N\] \[mss BYTES\] \[window BYTES\] \[reject\] \[IFACE\]\] Show or 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 -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 - **run-init** run-init \[-d CAP,CAP...\] \[-n\] \[-c CONSOLE\_DEV\] 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 -d CAPS Drop capabilities -n Dry run ``` - **run-parts** run-parts \[-a ARG\]... \[-u UMASK\] \[--reverse\] \[--test\] \[--exit-on-error\] DIRECTORY Run a bunch of scripts in DIRECTORY ``` -a ARG Pass ARG as argument to scripts -u UMASK Set UMASK before running scripts --reverse Reverse execution order --test Dry run --exit-on-error Exit if a script exits with non-zero ``` - **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 ``` 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 with leading zeros -s SEP String separator ``` - **setkeycodes** setkeycodes { SCANCODE KEYCODE }... Modify kernel's scancode-to-keycode map, allowing unusual keyboards to generate usable keycodes. SCANCODE is either xx or e0xx (hexadecimal), KEYCODE is decimal. - **setpriv** setpriv \[OPTIONS\] PROG ARGS Run PROG with different privilege settings \-d,--dump Show current capabilities --nnp,--no-new-privs Ignore setuid/setgid bits and file capabilities --inh-caps CAP,CAP Set inheritable capabilities --ambient-caps CAP,CAP Set ambient capabilities - **setsid** setsid \[-c\] PROG ARGS Run PROG in a new session. PROG will have no controlling terminal and will not be affected by keyboard signals (^C etc). ``` -c Set controlling terminal to stdin ``` - **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 ``` - **ssl\_client** ssl\_client \[-e\] -s FD \[-r FD\] \[-n SNI\] - **start-stop-daemon** start-stop-daemon -S\|-K \[OPTIONS\] \[-- ARGS\] Search for matching processes, and then -S: start a process unless a matching process is found -K: stop all matching processes Process matching: ``` -u USERNAME|UID Match only this user's processes -n NAME Match processes with NAME in comm field in /proc/PID/stat -x EXECUTABLE Match processes with this command in /proc/PID/cmdline -p FILE Match a process with PID from FILE All specified conditions must match -S only: -x EXECUTABLE Program to run -a NAME Zeroth argument -b Background -O FILE Append stdout and stderr to FILE -N N Change nice level -c USER[:[GRP]] Change user/group -d DIR Change to DIR -m Write PID to pidfile specified by -p -K only: -s SIG Signal to send -t Match only, exit with 0 if found Other: -o Exit with status 0 if nothing is done -v Verbose -q Quiet ``` - **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) ``` - **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 \[-lmp\] \[-s SH\] \[-\] \[USER \[FILE ARGS \| -c 'CMD' \[ARG0 ARGS\]\]\] Run shell under USER (by default, root) ``` -,-l Clear environment, go to home dir, 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 ``` -p Start a login shell -t SEC Timeout ``` - **svc** svc \[-udopchaitkx\] SERVICE\_DIR... Control services monitored by runsv supervisor ``` -u If service is not running, start it; restart if it stops -d If service is running, send TERM+CONT signals; do not restart it -o Once: if service is not running, start it; do not restart it -pchaitk Send STOP, CONT, HUP, ALRM, INT, TERM, KILL signal to service -x Exit: runsv will exit as soon as the service is down ``` - **svok** svok SERVICE\_DIR Check whether runsv supervisor is running. Exit code is 0 if it does, 100 if it does not, 111 (with error message) if SERVICE\_DIR does not exist. - **swapoff** swapoff \[-a\] \[DEVICE\] Stop swapping on DEVICE ``` -a Stop swapping on all swap devices ``` - **swapon** swapon \[-a\] \[-e\] \[-d\[POL\]\] \[DEVICE\] Start swapping on DEVICE ``` -a Start swapping on all swap devices -d[POL] Discard blocks at swapon (POL=once), as freed (POL=pages), or both (POL omitted) -e Silently skip devices that do not exist ``` - **switch\_root** switch\_root \[-c CONSOLE\_DEV\] 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 \[-df\] \[FILE\]... Write all buffered blocks (in FILEs) to disk\ \-d Avoid syncing metadata\ \-f Sync filesystems underlying FILEs - **sysctl** sysctl \[-enq\] { -a \| -p \[FILE\]... \| \[-w\] \[KEY\[=VALUE\]\]... } Show/set kernel parameters ``` -e Don't warn about unknown keys -n Don't show key names -q Quiet -a Show all values -p Set values from FILEs (default /etc/sysctl.conf) -w Set values ``` - **syslogd** syslogd \[OPTIONS\] System logging utility ``` -n Run in foreground -R HOST[:PORT] Log to HOST:PORT (default PORT:514) -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) -O FILE Log to FILE (default: /var/log/messages, stdout if -) -s SIZE Max size (KB) before rotation (default 200KB, 0=off) -b N N rotated logs to keep (default 1, max 99, 0=purge) -l N Log only messages more urgent than prio N (1-8) -S Smaller output -t Strip client-generated timestamps -D Drop duplicates -f FILE Use FILE as config (default:/etc/syslog.conf) ``` - **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 \[-ZzJjahmvokO\] \[-f TARFILE\] \[-C DIR\] \[FILE\]... 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 --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 --to-command COMMAND Pipe files to COMMAND ``` - **taskset** taskset \[-ap\] \[HEXMASK \| -c LIST\] { PID \| PROG ARGS } Set or get CPU affinity ``` -p Operate on PID -a Operate on all threads -c Affinity is a list, not mask ``` - **tc** tc OBJECT CMD \[dev STRING\] OBJECT: qdisc\|class\|filter CMD: add\|del\|change\|replace\|show qdisc \[handle QHANDLE\] \[root\|ingress\|parent CLASSID\]\ \[\[QDISC\_KIND\] \[help\|OPTIONS\]\]\ QDISC\_KIND := \[p\|b\]fifo\|tbf\|prio\|red\|etc. qdisc show \[dev STRING\] \[ingress\] class \[classid CLASSID\] \[root\|parent CLASSID\]\ \[\[QDISC\_KIND\] \[help\|OPTIONS\] \] class show \[ dev STRING \] \[root\|parent CLASSID\] filter \[pref PRIO\] \[protocol PROTO\]\ \[root\|classid CLASSID\] \[handle FILTERID\]\ \[\[FILTER\_TYPE\] \[help\|OPTIONS\]\] filter show \[dev STRING\] \[root\|parent CLASSID\] - **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 ``` - **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 in bytes ``` - **time** time \[-vpa\] \[-o FILE\] PROG ARGS Run PROG, display resource usage when it exits ``` -v Verbose -p POSIX output format -f FMT Custom 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. - **top** top \[-bH\] \[-n COUNT\] \[-d SECONDS\] Show a view of process activity in real time. Read the status of all processes from /proc each SECONDS and show 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 SEC Delay between updates -H Show threads ``` - **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 ``` - **traceroute** traceroute \[-46Flnrv\] \[-f 1ST\_TTL\] \[-m MAXTTL\] \[-q PROBES\] \[-p PORT\]\ \[-t TOS\] \[-w WAIT\_SEC\] \[-s SRC\_IP\] \[-i IFACE\]\ \[-z PAUSE\_MSEC\] HOST \[BYTES\] Trace the route to HOST ``` -4,-6 Force IP or IPv6 name resolution -F Set don't fragment bit -l Display TTL value of the returned packet -n Print numeric addresses -r Bypass routing tables, send directly to HOST -v Verbose -f N First number of hops (default 1) -m N Max number of hops -q N Number of probes per hop (default 3) -p N Base UDP port number used in probes (default 33434) -s IP Source address -i IFACE Source interface -t N Type-of-service in probe packets (default 0) -w SEC Wait for a response (default 3) -z MSEC Wait before each send ``` - **traceroute6** traceroute6 \[-nrv\] \[-f 1ST\_TTL\] \[-m MAXTTL\] \[-q PROBES\] \[-p PORT\]\ \[-t TOS\] \[-w WAIT\_SEC\] \[-s SRC\_IP\] \[-i IFACE\]\ \[-z PAUSE\_MSEC\] HOST \[BYTES\] Trace the route to HOST ``` -n Print numeric addresses -r Bypass routing tables, send directly to HOST -v Verbose -f N First number of hops (default 1) -m N Max number of hops -q N Number of probes per hop (default 3) -p N Base UDP port number used in probes (default 33434) -s IP Source address -i IFACE Source interface -t N Type-of-service in probe packets (default 0) -w SEC Wait for a response (default 3) -z MSEC Wait before each send ``` - **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 ``` - **tty** tty \[-s\] 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/TAP interfaces ``` -f DEV TUN device (default /dev/net/tun) -t NAME Create iface (default: tapN) -d NAME Delete iface ``` - **ubirename** ubirename UBI\_DEVICE OLD\_VOLNAME NEW\_VOLNAME \[OLD2 NEW2\]... Rename UBI volumes on UBI\_DEVICE - **udhcpc** udhcpc \[-fbqRB\] \[-a\[MSEC\]\] \[-t N\] \[-T SEC\] \[-A SEC\|-n\]\ \[-i IFACE\] \[-s PROG\] \[-p PIDFILE\]\ \[-oC\] \[-r IP\] \[-V VENDOR\] \[-F NAME\] \[-x OPT:VAL\]... \[-O OPT\]... ``` -i IFACE Interface to use (default eth0) -s PROG Run PROG at DHCP events (default /etc/udhcpc/default.script) -p FILE Create pidfile -B Request broadcast replies -t N Send up to N discover packets (default 3) -T SEC Pause between packets (default 3) -A SEC Wait if lease is not obtained (default 20) -b Background if lease is not obtained -n Exit if lease is not obtained -q Exit after obtaining lease -R Release IP on exit -f Run in foreground -S Log to syslog too -a[MSEC] Validate offered address with ARP ping -r IP Request this IP address -o Don't request any options (unless -O is given) -O OPT Request option OPT from server (cumulative) -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) -x 14:'"dumpfile"' - option 14 (shell-quoted) -F NAME Ask server to update DNS mapping for NAME -V VENDOR Vendor identifier (default 'udhcp VERSION') -C Don't send MAC as client identifier Signals: USR1 Renew lease USR2 Release lease ``` - **udhcpc6** udhcpc6 \[-fbqR\] \[-t N\] \[-T SEC\] \[-A SEC\|-n\] \[-i IFACE\] \[-s PROG\]\ \[-p PIDFILE\] \[-ldo\] \[-r IPv6\] \[-x OPT:VAL\]... \[-O OPT\]... ``` -i IFACE Interface to use (default eth0) -p FILE Create pidfile -s PROG Run PROG at DHCP events (default /etc/udhcpc/default6.script) -B Request broadcast replies -t N Send up to N discover packets -T SEC Pause between packets (default 3) -A SEC Wait if lease is not obtained (default 20) -b Background if lease is not obtained -n Exit if lease is not obtained -q Exit after obtaining lease -R Release IP on exit -f Run in foreground -S Log to syslog too -l Send 'information request' instead of 'solicit' (used for servers which do not assign IPv6 addresses) -r IPv6 Request this address ('no' to not request any IP) -d Request prefix -o Don't request any options (unless -O is given) -O OPT Request option OPT from server (cumulative) -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) -x 14:'"dumpfile"' - option 14 (shell-quoted) Signals: USR1 Renew lease USR2 Release lease ``` - **udhcpd** udhcpd \[-fS\] \[-I ADDR\] \[-a MSEC\] \[CONFFILE\] DHCP server ``` -f Run in foreground -S Log to syslog too -I ADDR Local address -a MSEC Timeout for ARP ping (default 2000) Signals: USR1 Update lease file ``` - **uevent** uevent \[PROG ARGS\] uevent runs PROG for every netlink notification. PROG's environment contains data passed from the kernel. Typical usage (daemon for dynamic device node creation):\ \# uevent mdev & mdev -s - **umount** umount \[-rlfda\] \[-t FSTYPE\] FILESYSTEM\|DIRECTORY Unmount filesystems ``` -a Unmount all filesystems -r Remount devices read-only if mount is busy -l Lazy umount (detach filesystem) -f Force umount (i.e., unreachable NFS server) -d Free loop device if it has been used -t FSTYPE[,...] Unmount only these filesystem type(s) ``` - **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** 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 ``` - **unshare** unshare \[OPTIONS\] \[PROG ARGS\] ``` -m,--mount[=FILE] Unshare mount namespace -u,--uts[=FILE] Unshare UTS namespace (hostname etc.) -i,--ipc[=FILE] Unshare System V IPC namespace -n,--net[=FILE] Unshare network namespace -p,--pid[=FILE] Unshare PID namespace -U,--user[=FILE] Unshare user namespace -f Fork before execing PROG -r Map current user to root (implies -U) --mount-proc[=DIR] Mount /proc filesystem first (implies -m) --propagation slave|shared|private|unchanged Modify mount propagation in mount namespace --setgroups allow|deny Control the setgroups syscall in user namespaces ``` - **unxz** unxz \[-cfk\] \[FILE\]... Decompress FILEs (or stdin) ``` -c Write to stdout -f Force -k Keep input files -t Test integrity ``` - **unzip** unzip \[-lnojpqK\] 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 -K Do not clear SUID bit -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 ``` - **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 \[-c CMD\] \[-R\] \[-H\] \[FILE\]... Edit FILE ``` -c CMD Initial command to run ($EXINIT and ~/.exrc also available) -R Read-only -H List available features ``` - **w** w Show who is logged on - **watch** watch \[-n SEC\] \[-t\] PROG ARGS Run PROG periodically ``` -n SEC Period (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 FILEs (or stdin) ``` -c Count bytes -m Count characters -l Count newlines -w Count words -L Print longest line length ``` - **wget** wget \[-cqS\] \[--spider\] \[-O FILE\] \[-o LOGFILE\] \[--header STR\]\ \[--post-data STR \| --post-file FILE\] \[-Y on/off\]\ \[--no-check-certificate\] \[-P DIR\] \[-U AGENT\] \[-T SEC\] 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 --no-check-certificate Don't validate the server's certificate -c Continue retrieval of aborted transfer -q Quiet -P DIR Save to DIR (default .) -S Show server response -T SEC Network read timeout is SEC seconds -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 ``` - **who** who \[-aH\] 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 ``` -0 NUL terminated input -a FILE Read from FILE instead of stdin -o Reopen stdin as /dev/tty -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 \[-pri\] \[-g N\] \[-c N\] \[-l LEN\] \[-s OFS\] \[-o OFS\] \[FILE\] 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 ## 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 \ ## 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 \ ``` run-parts ``` Erik Andersen \ ``` 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 \ ``` rpm2cpio, unzip, get_header_cpio, read_gz interface, rpm ``` Jeff Angielski \ ``` ftpput, ftpget ``` Edward Betts \ ``` expr, hostid, logname, whoami ``` John Beppu \ ``` du, nslookup, sort ``` Brian Candler \ ``` tiny-ls(ls) ``` Randolph Chung \ ``` fbset, ping, hostname ``` Dave Cinege \ ``` more(v2), makedevs, dutmp, modularization, auto links file, various fixes, Linux Router Project maintenance ``` Jordan Crouse \ ``` ipcalc ``` Magnus Damm \ ``` tftp client insmod powerpc support ``` Larry Doolittle \ ``` pristine source directory compilation, lots of patches and fixes. ``` Glenn Engel \ ``` httpd ``` Gennady Feldman \ ``` Sysklogd (single threaded syslogd, IPC Circular buffer support, logread), various fixes. ``` Karl M. Hegbloom \ ``` cp_mv.c, the test suite, various fixes to utility.c, &c. ``` Daniel Jacobowitz \ ``` mktemp.c ``` Matt Kraai \ ``` documentation, bugfixes, test suite ``` Stephan Linz \ ``` ipcalc, Red Hat equivalence ``` John Lombardo \ ``` tr ``` Glenn McGrath \ ``` Common unarchiving code and unarchiving applets, ifupdown, ftpgetput, nameif, sed, patch, fold, install, uudecode. Various bugfixes, review and apply numerous patches. ``` Manuel Novoa III \ ``` 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 \ ``` 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 \ ``` Original author of BusyBox in 1995, 1996. Some of his code can still be found hiding here and there... ``` Tim Riker \ ``` bug fixes, member of fan club ``` Kent Robotti \ ``` reset, tons and tons of bug reports and patches. ``` Chip Rosenthal \, \ ``` wget - Contributed by permission of Covad Communications ``` Pavel Roskin \ ``` Lots of bugs fixes and patches. ``` Gyepi Sam \ ``` Remote logging feature for syslogd ``` Linus Torvalds \ ``` mkswap, fsck.minix, mkfs.minix ``` Mark Whitley \ ``` grep, sed, cut, xargs(previous), style-guide, new-applet-HOWTO, bug fixes, etc. ``` Charles P. Wright \ ``` gzip, mini-netcat(nc) ``` Enrique Zanardi \ ``` tarcat (since removed), loadkmap, various fixes, Debian maintenance ``` Tito Ragusa \ ``` devfsd and size optimizations in strings, openvt and deallocvt. ``` Paul Fox \ ``` vi editing mode for ash, various other patches/fixes ``` Roberto A. Foglietta \ ``` port: dnsd ``` Bernhard Reutner-Fischer \ ``` misc ``` Mike Frysinger \ ``` initial e2fsprogs, printenv, setarch, sum, misc ``` Jie Zhang \ ``` fixed two bugs in msh and hush (exitcode of killed processes) ```