A
alias - Create an alias •
apropos - Search Help manual pages (man -k)
apt-get - Search for and install software packages (Debian/Ubuntu)
aptitude - Search for and install software packages (Debian/Ubuntu)
aspell - Spell Checker
awk - Find and Replace text, database sort/validate/index
B
basename - Strip directory and suffix from filenames
bash - GNU Bourne-Again SHell
bc - Arbitrary precision calculator language
bg - Send to background
break - Exit from a loop •
builtin - Run a shell builtin
bzip2 - Compress or decompress named file(s)
C
cal - Display a calendar
case - Conditionally perform a command
cat - Concatenate and print (display) the content of files
cd - Change Directory
cfdisk - Partition table manipulator for Linux
chgrp - Change group ownership
chmod - Change access permissions
chown - Change file owner and group
chroot - Run a command with a different root directory
chkconfig - System services (runlevel)
cksum - Print CRC checksum and byte counts
clear - Clear terminal screen
cmp - Compare two files
comm - Compare two sorted files line by line
command - Run a command - ignoring shell functions •
continue - Resume the next iteration of a loop •
cp - Copy one or more files to another location
cron - Daemon to execute scheduled commands
crontab - Schedule a command to run at a later time
csplit - Split a file into context-determined pieces
cut - Divide a file into several parts
D
date - Display or change the date & time
dc - Desk Calculator
dd - Convert and copy a file, write disk headers, boot records
ddrescue - Data recovery tool
declare - Declare variables and give them attributes •
df - Display free disk space
diff - Display the differences between two files
diff3 - Show differences among three files
dig - DNS lookup
dir - Briefly list directory contents
dircolors - Colour setup for `ls'
dirname - Convert a full pathname to just a path
dirs - Display list of remembered directories
dmesg - Print kernel & driver messages
du - Estimate file space usage
E
echo - Display message on screen •
egrep - Search file(s) for lines that match an extended expression
eject - Eject removable media
enable - Enable and disable builtin shell commands •
env - Environment variables
ethtool - Ethernet card settings
eval - Evaluate several commands/arguments
exec - Execute a command
exit - Exit the shell
expect - Automate arbitrary applications accessed over a terminal
expand - Convert tabs to spaces
export - Set an environment variable
expr - Evaluate expressions
F
false - Do nothing, unsuccessfully
fdformat - Low-level format a floppy disk
fdisk - Partition table manipulator for Linux
fg - Send job to foreground
fgrep - Search file(s) for lines that match a fixed string
file - Determine file type
find - Search for files that meet a desired criteria
fmt - Reformat paragraph text
fold - Wrap text to fit a specified width.
for - Expand words, and execute commands
format - Format disks or tapes
free - Display memory usage
fsck - File system consistency check and repair
ftp - File Transfer Protocol
function - Define Function Macros
fuser - Identify/kill the process that is accessing a file
G
gawk - Find and Replace text within file(s)
getopts - Parse positional parameters
grep - Search file(s) for lines that match a given pattern
groupadd - Add a user security group
groupdel - Delete a group
groupmod - Modify a group
groups - Print group names a user is in
gzip - Compress or decompress named file(s)
H
hash - Remember the full pathname of a name argument
head - Output the first part of file(s)
help - Display help for a built-in command •
history - Command History
hostname - Print or set system name
I
iconv - Convert the character set of a file
id - Print user and group id's
if - Conditionally perform a command
ifconfig - Configure a network interface
ifdown - Stop a network interface
ifup - Start a network interface up
import - Capture an X server screen and save the image to file
install - Copy files and set attributes
J
jobs - List active jobs •
join - Join lines on a common field
K
kill - Stop a process from running
killall - Kill processes by name
L
less - Display output one screen at a time
let - Perform arithmetic on shell variables •
link - Create a link to a file
ln - Create a symbolic link to a file
local - Create variables •
locate - Find files
logname - Print current login name
logout - Exit a login shell •
look - Display lines beginning with a given string
lpc - Line printer control program
lpr - Off line print
lprint - Print a file
lprintd - Abort a print job
lprintq - List the print queue
lprm - Remove jobs from the print queue
ls - List information about file(s)
lsof - List open files
M
make - Recompile a group of programs
man - Help manual
mkdir - Create new folder(s)
mkfifo - Make FIFOs (named pipes)
mkisofs - Create an hybrid ISO9660/JOLIET/HFS filesystem
mknod - Make block or character special files
more - Display output one screen at a time
mount - Mount a file system
mtools - Manipulate MS-DOS files
mtr - Network diagnostics (traceroute/ping)
mv - Move or rename files or directories
mmv - Mass Move and rename (files)
N
netstat - Networking information
nice - Set the priority of a command or job
nl - Number lines and write files
nohup - Run a command immune to hangups
notify-send - Send desktop notifications
nslookup - Query Internet name servers interactively
O
open - Open a file in its default application
op - Operator access
P
passwd - Modify a user password
paste - Merge lines of files
pathchk - Check file name portability
ping - Test a network connection
pkill - Stop processes from running
popd - Restore the previous value of the current directory
pr - Prepare files for printing
printcap - Printer capability database
printenv - Print environment variables
printf - Format and print data •
ps - Process status
pushd - Save and then change the current directory
pv - Monitor the progress of data through a pipe
pwd - Print Working Directory
Q
quota - Display disk usage and limits
quotacheck - Scan a file system for disk usage
quotactl - Set disk quotas
R
ram - ram disk device
rcp - Copy files between two machines
read - Read a line from standard input •
readarray - Read from stdin into an array variable •
readonly - Mark variables/functions as readonly
reboot - Reboot the system
rename - Rename files
renice - Alter priority of running processes
remsync - Synchronize remote files via email
return - Exit a shell function
rev - Reverse lines of a file
rm - Remove files
rmdir - Remove folder(s)
rsync - Remote file copy (Synchronize file trees)
S
screen - Multiplex terminal, run remote shells via ssh
scp - Secure copy (remote file copy)
sdiff - Merge two files interactively
sed - Stream Editor
select - Accept keyboard input
seq - Print numeric sequences
set - Manipulate shell variables and functions
sftp - Secure File Transfer Program
shift - Shift positional parameters
shopt - Shell Options
shutdown - Shutdown or restart linux
sleep - Delay for a specified time
slocate - Find files
sort - Sort text files
source - Run commands from a file '.'
split - Split a file into fixed-size pieces
ssh - Secure Shell client (remote login program)
strace - Trace system calls and signals
su - Substitute user identity
sudo - Execute a command as another user
sum - Print a checksum for a file
suspend - Suspend execution of this shell •
sync - Synchronize data on disk with memory
T
tail - Output the last part of file
tar - Store, list or extract files in an archive
tee - Redirect output to multiple files
test - Evaluate a conditional expression
time - Measure Program running time
timeout - Run a command with a time limit
times - User and system times
touch - Change file timestamps
top - List processes running on the system
traceroute - Trace Route to Host
trap - Run a command when a signal is set(bourne)
tr - Translate, squeeze, and/or delete characters
true - Do nothing, successfully
tsort - Topological sort
tty - Print filename of terminal on stdin
type - Describe a command •
U
ulimit - Limit user resources •
umask - Users file creation mask
umount - Unmount a device
unalias - Remove an alias •
uname - Print system information
unexpand - Convert spaces to tabs
uniq - Uniquify files
units - Convert units from one scale to another
unset - Remove variable or function names
unshar - Unpack shell archive scripts
until - Execute commands (until error)
uptime - Show uptime
useradd - Create new user account
userdel - Delete a user account
usermod - Modify user account
users - List users currently logged in
uuencode - Encode a binary file
uudecode - Decode a file created by uuencode
V
v - Verbosely list directory contents (`ls -l -b')
vdir - Verbosely list directory contents (`ls -l -b')
vi - Text Editor
vmstat - Report virtual memory statistics
W
wait - Wait for a process to complete •
watch - Execute/display a program periodically
wc - Print byte, word, and line counts
whereis - Search the user's $path, man pages and source files for a program
which - Search the user's $path for a program file
while - Execute commands
who - Print all usernames currently logged in
whoami - Print the current user id and name (`id -un')
wget - Retrieve web pages or files via HTTP, HTTPS or FTP
write - Send a message to another user
X
xargs - Execute utility, passing constructed argument list(s)
xdg-open - Open a file or URL in the user's preferred application.
Y
yes - Print a string until interrupted
Z
zip - Package and compress (archive) files.
Other
. - Run a command script in the current shell
!! - Run the last command again
### - Comment / Remark
