Useful Unix Commands Sorted Into Groups

# directory manipulation:
ls (ll) - list directory contents
dir - list directory contents
vdir - list directory contents
dircolors - color setup for ls
cd - change current/working directory
pwd - print name of current/working directory
mkdir - make directories
rmdir - remove empty directories
namei - follow a pathname until a terminal point is found
dirs - displays the list of currently remembered directories
pushd - adds a directory to the top of the directory stack
popd - removes entries from the directory stack
pathchk - check whether file names are valid or portable

# file manipulation:
cp - copy files and/or directories
install - copy files and set attributes
mv - move/rename files
rename - rename files
basename - strip directory and suffix from filenames
dirname - strip non-directory suffix from file name
rm - remove files or directories
shred - delete a file securely, first overwriting it to hide its contents
ln - make links between files
link - call the link function to create a link to a file
unlink - call the unlink function to remove the specified file
readlink - print contents of symbolic link
alternatives - maintain symbolic links determining default commands
file - determine file type
touch - change file timestamps
chattr - change file attributes on a Linux second extended file system
lsattr - list file attributes on a Linux second extended file system
mkfifo - make FIFOs (named pipes)
mknod - make block or character special files
mktemp - make temporary file name (unique)

# access rights/owner
chown - change file owner and group
chgrp - change group ownership
chmod - change file access permissions
access - determine whether a file can be accessed
chacl - change the access control list of a file or directory
setfacl - set file access control lists
setfattr - set extended attributes of filesystem objects
umask - set the user file creation mask
whoami - print effective userid
groups - print the groups a user is in
id - print real and effective UIDs and GIDs
logname - print user´s login name
chfn - change your finger information
chsh - change your login shell

# search for files/content
find - search for files in a directory hierarchy
which - shows the full path of (shell) commands
type - shows the full path of (shell) commands (bash only)
where - shows the full path of (shell) commands (tcsh only)
whereis - locate the binary, source, and manual page files for a command
grep, egrep, fgrep - print lines matching a pattern (string)
look - display lines beginning with a given string
xargs - build and execute command lines from standard input

# compare files
test - check file types and compare values
cmp - compare two files
comm - compare two sorted files line by line
diff - find differences between two files
diff3 - find differences between three files
diffstat - make histogram from diff-output
pdiff - produce a pretty comparison between files
sdiff - find differences between two files and merge interactively
rediff, editdiff - fix offsets and counts of a hand-edited diff
sum - checksum and count the blocks in a file
cksum - checksum and count the bytes in a file
md5sum - compute and check MD5 message digest
sha1sum - compute and check SHA1 message digest
ptx - produce a permuted index of file contents
fam - file alteration monitor
gendiff - utility to aid in error-free diff file generation
lsdiff - show which files are modified by a patch
splitdiff - separate out incremental patches
patch - apply a diff file to an original
newer - compare file modification times

# show file contents
cat - concatenate files and print on the standard output
tac - concatenate and print files in reverse
more - file perusal filter for crt viewing
less - file perusal filter for crt viewing
head - output the first part of files
tail - output the last part of files
column - columnate lists
hexdump - ascii, decimal, hexadecimal, octal dump
xxd - make a hexdump or do the reverse
od - dump files in octal and other formats
pr - convert text files for printing
wc - print the number of bytes, words, and lines in files
nl - number lines of files
printf - format and print data
lv - a Powerful Multilingual File Viewer
strings - print the strings of printable characters in files

# modify files
sort - sort lines of text files
tsort - perform topological sort
cssort - Czech sort
uniq - remove duplicate lines from a sorted file
split - split a file into pieces
csplit - split a file into sections determined by context lines
cut - remove sections from each line of files
paste - merge lines of files
join - join lines of two files on a common field
merge - three-way file merge
expand - convert tabs to spaces
unexpand - convert spaces to tabs
colrm - remove columns from a file
rev - reverse lines of a file
col - filter reverse line feeds from input
ul - do underlining
fmt - simple optimal text formatter
fold - wrap each input line to fit in specified width
join - join lines of two files on a common field
paste - merge lines of files
tr - translate or delete characters
cstocs - charset encoding convertor for the Czech and Slovak languages
enca - guess encoding of text files and convert them if required
recode - convert files between various character sets and surfaces
iconv - convert encoding of given files from one encoding to another
unix2dos - UNIX to DOS text file format converter
dos2unix - DOS/MAC to UNIX text file format converter

# editors
ed, red - text editor
sed - a Stream EDitor
awk, gawk - pattern scanning and processing language
igawk - gawk with include files
vi, vim - Vi IMproved, a programmers text editor
vimdiff - edit two or three versions of a file with Vim and show differences
vimtutor - the Vim tutor
xxd - make a hexdump or do the reverse
emacs - handle outline editing, compiling, running subshells, ...
pico - simple text editor in the style of the Pine Composer
makeindex - a general purpose, formatter-independent index processor
aspell
ispell
pdffonts - Portable Document Format (PDF) font analyzer
pdfimages - Portable Document Format (PDF) image extractor
pdfinfo - Portable Document Format (PDF) document information extractor
pdftotext - Portable Document Format (PDF) to text converter

# compress files
tar - the GNU version of the tar archiving utility
gzip, gunzip, zcat - compress or expand files
zgrep, zegrep, zfgrep - search possibly compressed files for a regular expression
znew - recompress .Z files to .gz files
zcmp, zdiff - compare compressed files
zmore - file perusal filter for crt viewing of compressed text
zless - file perusal filter for crt viewing of compressed text
zforce - force a .gz extension on all gzip files
gzexe - compress executable files in place
bzip2, bunzip2 - a block-sorting file compressor
bzip2recover - recovers data from damaged bzip2 files
bzcat - decompresses files to stdout
bzmore, bzless - file perusal filter for crt viewing of bzip2 compressed text
bzcmp, bzdiff - compare bzip2 compressed files
bzgrep, bzfgrep, bzegrep - search possibly bzip2 compressed files for a regular expression
zip, zipcloak, zipnote, zipsplit - package and compress (archive) files
unzip - list, test and extract compressed files in a ZIP archive
funzip - filter for extracting from a ZIP archive in a pipe
unzipsfx - self-extracting stub for prepending to ZIP archives
zipgrep - search files in a ZIP archive for lines matching a pattern
zipinfo - list detailed information about a ZIP archive
cpio - copy files to and from archives
lha
unarj
unrar
ar - create, modify, and extract from archives
pax - read and write file archives and copy directory hierarchies
ranlib - generate index to archive

# disk manipulation
mount - mount a file system
umount - unmount file systems
eject - eject removable media
sync - flush filesystem buffers
dd - convert and copy a file
df - report filesystem disk space usage
isosize - outputs the length of a iso9660 file system
du - estimate file space usage
quota - display disk usage and limits
edquota - edit user quotas
repquota - summarize quotas for a filesystem
setquota - set disk quotas
warnquota - send mail to users over quota
fdisk - partition table manipulator
sfdisk - partition table manipulators
ide_info - IDE device description tool
badblocks - search a device for bad blocks
fdformat - low-level formats a floppy disk
setfdprm - sets user-provided floppy disk parameters
hdparm - get/set hard disk parameters
mkfs - build a Linux file system
mkfs.minix - make a Linux MINIX filesystem
mke2fs - create a Linux second extended file system
fsck - check and repair a Linux file system
e2fsck - check a Linux second extended file system
debugfs - ext2 file system debugger
dumpe2fs - dump filesystem information
e2image - Save critical ext2 filesystem data to a file
e2label - Change the label on an ext2 filesystem
resize2fs - ext2 file system resizer
tune2fs - adjust tunable filesystem parameters on second extended filesystems
mklost+found - create a lost+found directory on a mounted Linux second extended file system
mkswap - set up a Linux swap area
swapon, swapoff - enable/disable devices and files for paging and swapping
mt - control magnetic tape drive operation
stinit - initialize SCSI magnetic tape drives
mkisofs - create an hybrid ISO9660/JOLIET/HFS filesystem with optional Rock Ridge attributes
devdump, isoinfo, isovfy, isodump - utility programs for dumping and verifying iso9660 images
isosize - outputs the length of a iso9660 file system
volname - return volume name
minfo - print the parameters of a MSDOS filesystem
updfstab - update /etc/fstab to reflect removable devices

# shells
sh - command interpreter (shell)
ash - command interpreter (shell)
bsh - command interpreter (shell)
bash - GNU Bourne-Again SHell
csh - C shell with file name completion and command line editing
tcsh - C shell with file name completion and command line editing
ksh
zsk
nash - script interpretor to interpret linuxrc images
tclsh - Simple shell containing Tcl interpreter
mc - Visual shell for Unix-like systems
pilot - simple file system browser in the style of the Pine Composer
dialog - display dialog boxes from shell scripts
gdialog - display dialog boxes from shell scripts

# system info
w - show who is logged on and what they are doing
who - show who is logged on
whois, fwhois - query a whois or nicname database
users - print the user names of users currently logged in to the current host
last, lastb - show listing of last logged in users
arch - print machine architecture
kernelversion - program to report major version of kernel
lsmod - list loaded modules
modinfo - display information about a kernel module
uname - print system information
uptime - tell how long the system has been running
ps - report process status
pstree - display a tree of processes
top - display top CPU processes
tload - graphic representation of system load average
skill, snice - report process status
pidof - find the process ID of a running program
free - display amount of free and used memory in the system
fuser - identify processes using files or sockets
runlevel - find the current and previous system runlevel
dmesg - print or control the kernel ring buffer
ipcs - provide information on ipc facilities
readprofile - a tool to read kernel profiling information
hostid - print the numeric identifier for the current host
pinky - lightweight finger
printenv - print all or part of environment
tty - print the file name of the terminal connected to standard input
consoletype - print type of the console connected to standard input
script - make typescript of terminal session
ldd - print shared library dependencies
mev - a program to report mouse events
sensors - printing sensors information
showkey - examine the codes sent by the keyboard
size - list section sizes and total size
strace - trace system calls and signals
vmstat - report virtual memory statistics

# system control
echo - output the arguments, separated by spaces, followed by a newline
history - display the command history list with line numbers
getopt - parse command options (enhanced)
setsid - run a program in a new session
watch - execute a program periodically, showing output fullscreen
read - one line is read from the standard input
bg - resume the suspended job in the background
fg - resume job in the foreground and make it the current job
jobs - list the active jobs
disown - removes jobs from the table of active jobs
nice - run a program with modified scheduling priority
renice - alter priority of running processes
kill - send a signal to the processes named by pid or jobspec
killall - kill processes by name
pgrep, pkill - look up or signal processes based on name and other attributes
nohup - run a command immune to hangups, with output to a non-tty
time - time a simple command or give resource usage
times - print the accumulated user and system times for the shell
ulimit - provides control over the resources available to the shell
tzselect - select a time zone
zic - time zone compiler
ipcrm - remove a message queue, semaphore set or shared memory id
setterm - set terminal attributes
tunelp - set various parameters for the lp device
env - run a program in a modified environment
doexec - run an executable with an arbitrary argv[0]
stty - change and print terminal line settings
deallocvt - deallocate unused virtual consoles
chvt - change foreground virtual terminal
openvt - start a program on a new virtual terminal (VT)
tset, reset - terminal initialization
resizecons - change kernel idea of the console size
screen - screen manager with VT100/ANSI terminal emulation
gpm - a cut and paste utility and mouse server for virtual consoles
mesg - control write access to your terminal
hostname - show or set the system´s host name
initlog - log messages and events to the system logger
sys-unconfig - shell script to reconfigure the system upon next boot
kbdconfig - simple interface for configuring system keyboard
kbdrate - reset the keyboard repeat rate and delay time
setkeycodes - load kernel scancode-to-keycode mapping table entries
setleds - set the keyboard leds
setmetamode - define the keyboard meta key handling
setup - setup devices and file systems, mount root file system
logwatch - system log analyzer and reporter
logrotate - rotates, compresses, and mails system logs

# system manipulation
mingetty - minimal getty for consoles
agetty - alternative Linux getty
login - sign on
logout - exit a login shell
exit - cause the shell to exit
su - run a shell with substitute user and group IDs
sudo - execute a command as another user
suexec - Switch User For Exec
sulogin - single-user login
nologin - politely refuse a login
faillog - examine faillog and set login failure limits
passwd - update a user´s authentication tokens(s)
chpasswd - update password file in batch
pwck - verify integrity of password files
smbpasswd - change a user?s SMB password
chage - change user password expiry information
faillog - examine faillog and set login failure limits
lastlog - examine lastlog file
adduser, useradd - create a new user or update default new user information
newusers - update and create new users in batch
userdel - delete a user account and related files
usermod - modify a user account
pwck - verify integrity of password files
groupadd - create a new group
groupdel - delete a group
groupmod - modify a group
grpck - verify integrity of group files
pwconv, pwunconv, grpconv, grpunconv - convert to and from shadow passwords and groups
newgrp - log in to a new group
gpasswd - administer the /etc/group file
vipw, vigr - edit the password or group files
visudo - edit the sudoers file
init - process control initialization
telinit - process control initialization
ntsysv - simple interface for configuring runlevels
chkconfig - updates and queries runlevel information for system services
shutdown - bring the system down
halt, reboot, poweroff - stop the system
ctrlaltdel - set the function of the Ctrl-Alt-Del combination
pivot_root - change the root file system
chroot - run command or interactive shell with special root directory
depmod - handle dependency descriptions for loadable kernel modules
insmod - install loadable kernel module
modprobe - high level handling of loadable modules
rmmod - unload loadable modules
raw - bind a Linux raw character device
kudzu - detects and configures new and/or changed hardware on a system
lockdev, liblockdev, dev_testlock, dev_lock, dev_relock, dev_unlock - manage device lockfiles
tmpwatch - removes files which haven?t been accessed for a period of time

# networking
ifconfig - configure a network interface
route - show / manipulate the IP routing table
ethtool - display or change ethernet card settings
ping, ping6 - send ICMP ECHO_REQUEST to network hosts
traceroute - print the route packets take to network host
tracepath, tracepath6 - traces path to a network host discovering MTU along this path
tcpdump - dump traffic on a network
tcpslice - extract pieces of and/or glue together tcpdump files
mtr - a network diagnostic tool
netstat - print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships
netreport - request notification of network interface changes
ifuser - identify destinations routed to a particular network interface
nameif - name network interfaces based on MAC addresses
usernetctl - allow a user to manipulate a network interface if permitted
arp - manipulate the system ARP cache
arping - send ARP REQUEST to a neighbour host
rdisc - network router discovery daemon
ipcalc - perform simple manipulation of IP addresses
domainname - show or set the system´s NIS/YP domain name
dnsdomainname - show the system´s DNS domain name
nisdomainname - show or set system´s NIS/YP domain name
ypdomainname - show or set the system´s NIS/YP domain name
nodename - show or set the system´s DECnet node name
mii-tool - view, manipulate media-independent interface status
pppdump - convert PPP record file to readable format
pppstats - print PPP statistics
chat - automated conversational script with a modem
wvdial - PPP dialer with built?in intelligence
plipconfig - fine tune PLIP device parameters
slattach - attach a network interface to a serial line
setserial - get/set Linux serial port information
ppp-watch - daemon to make PPP interfaces act more like other interfaces
statserial - display serial port modem status lines
dig - DNS lookup utility
host - DNS lookup utility
nslookup - query Internet name servers interactively
nsupdate - Dynamic DNS update utility
rndc - name server control utility
nmblookup - NetBIOS over TCP/IP client used to lookup NetBIOS names
nmap - network exploration tool and security scanner
rx, rb, rz - XMODEM, YMODEM, ZMODEM (Batch) file receive
sx, sb, sz - XMODEM, YMODEM, ZMODEM file send
stunnel - universal SSL tunnel

# network clients
ftp - internet file transfer program
ncftp - browser program for the File Transfer Protocol
sftp - Secure file transfer program
scp - secure copy (remote file copy program)
lynx - a general purpose distributed information browser for the World Wide Web
links - lynx-like alternative character mode WWW browser
wget - utility for non-interactive download of files from the Web
mail - send and receive mail
write - send a message to another user
wall - send a message to everybody´s terminal
pine - a Program for Internet News and Email
formail - mail (re)formatter
mailstats - display mail statistics
mutt - The Mutt Mail User Agent
urlview - URL extractor/launcher
ssh - OpenSSH SSH client (remote login program)
telnet - user interface to the TELNET protocol
finger - user information lookup program
pinky - lightweight finger
smbclient - ftp-like client to access SMB/CIFS resources on servers
smbmnt - helper utility for mounting SMB filesystems
smbmount - mount an smbfs filesystem
smbumount - smbfs umount for normal users
testprns - check printer name for validity with smbd
minicom - friendly serial communication program
runscript - script interpreter for minicom
rdate - get the time via the network
talk - talk to another user

# daemons and servers
crond - daemon to execute scheduled commands (Vixie Cron)
syslogd - Linux system logging utilities
lpd - line printer daemon
xfs - X font server
pppd - Point to Point Protocol daemon
inetd - internet "super-server"
xinetd - the extended Internet services daemon
tcpd - access control facility for internet services
vsftpd - Very Secure FTP Daemon
httpd - Apache hypertext transfer protocol server
webalizer - a web server log file analysis tool
sshd - OpenSSH SSH daemon
sendmail - mail delivery system
smail - mail delivery system
qmail - mail delivery system
fetchmail - fetch mail from a POP, IMAP, ETRN, or ODMR-capable server
procmail - autonomous mail processor
exportfs - maintain list of NFS exported file systems
nfsstat - print NFS statistics
nhfsstone - Network File System benchmark program
showmount - show mount information for an NFS server
pmap_dump - print a list of all registered RPC programs
pmap_set - set the list of registered RPC programs
rpcinfo - report RPC information
rdisc - network router discovery daemon
smbd
nmbd
testparm - check an smb.conf configuration file for internal correctness

# multimedia
play - play any sound file to audio device
showriff - show structure of RIFF files (wav, avi, ...)
sox - Sound eXchange : universal sound sample translator
rec - record audio to any sound file format
record - records *.wav files
streamer - record audio and/or video
cdplay - an interactive text-mode program for controlling and playing audio CD Roms
cdrecord - record audio or data Compact Discs from a master
dvdrecord - record audio or data Compact Discs and DVDs from a master
esd - The Enlightened Sound Daemon
oggenc - encode audio into the Ogg Vorbis format
oggdec - simple decoder, Ogg Vorbis file to PCM audio file (WAV or RAW)
ogginfo - gives information about Ogg files, and does extensive validity checking
ogg123 - plays Ogg Vorbis files
vcut - cuts Ogg Vorbis files
timidity - MIDI to WAV converter and player
cjpeg - compress an image file to a JPEG file
djpeg - decompress a JPEG file to an image file
thumbnail - create a TIFF file with thumbnail images
tiffcp - copy (and possibly convert) a TIFF file
tiffdump - print verbatim information about TIFF files
tiffinfo - print information about TIFF files
tiffsplit - split a multi-image TIFF into single-image TIFF files
pamcut - cut a rectangle out of a PAM, PBM, PGM, or PPM image
pamdeinterlace - remove ever other row from a PAM/PNM image
pamfile - describe a Netpbm (PAM or PNM) file
pamoil - turn a PAM image into an oil painting
pcdindex - create index image for a photo CD
pnmcat - concatenate portable anymaps
pnmcut - cut a rectangle out of a PBM, PGM, or PPM image
pnmfile - describe a portable anymap
pnmflip - perform one or more flip operations on a portable anymap
ppmfade - generate a transition between two image files using special effects
ppmdither - ordered dither for color images
ppmrainbow - generate a rainbow
ppmtv - make a portable pixmap look like taken from an American TV
radio - console radio application
fbset - show and modify frame buffer device settings

# miscelaneous
sleep - delay for a specified amount of time
usleep - sleep some number of microseconds
at, batch, atq, atrm - queue, examine or delete jobs for later execution
atrun - run jobs queued for later execution
clock - determine processor time
hwclock - query and set the hardware clock (RTC)
setclock - sets the hardware clock from the system clock
clockdiff - measure clock difference between hosts
date - print or set the system date and time
ddate - converts Gregorian dates to Discordian dates
cal - displays a calendar
units - unit conversion program
bc - an arbitrary precision calculator language
dc - an arbitrary precision calculator
octave - a high-level interactive language for numerical computations
expr - evaluate expressions
factor - print the prime factors of each number
seq - print a sequence of numbers
flex - fast lexical analyzer generator
clear - clear the terminal screen
true - do nothing, successfully
false - do nothing, unsuccessfully
yes - output a string repeatedly until killed
tee - read from standard input and write to standard output and files
lp - send requests to an LPRng print service
lpc - line printer control program
lpd - line printer daemon
lpq - spool queue examination program
lpr - off line print
lprm - remove jobs from the line printer spooling queue
lpstat - print information about the status of the LP print service
monitor - receive logging information from LPD
tunelp - set various parameters for the lp device
man - format and display the on-line manual pages
manpath - determine user´s search path for man pages
info - read Info documents
pinfo - curses based lynx-style info browser
whatis - search the whatis database for complete words
apropos - search the whatis database for strings
card - print reference card of program options
rpm - RPM Package Manager

Copyright (c) 2003 Bohdan Milar