Quick reference Linux commands

alias - Create an alias

awk - Find and Replace text, database sort/validate/index

break - Exit from a loop

builtin - Run a shell builtin

cal - Display a calendar

cse - Conditionally perform a command

cat - Display the contents of a file

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

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

date - Display or change the date & time

dc - Desk Calculator

dd - Data Dump - Convert and copy a file

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

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

du - Estimate file space usage

echo - Display message on screen ed A line-oriented text editor (edlin)

egrep - Search file(s) for lines that match an extended expression eject Eject CD-ROM

enable - Enable and disable builtin shell commands

env - Display, set, or remove environment variables

eval - Evaluate several commands/arguments

exec - Execute a command exit Exit the shell

expand - Convert tabs to spaces

export - Set an environment variable

expr - Evaluate expressions

factor - Print prime factors

false - Do nothing, unsuccessfully

fdformat - Low-level format a floppy disk

fdisk - Partition table manipulator for Linux

fgrep - Search file(s) for lines that match a fixed string

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 - Filesystem consistency check and repair.

function - Define Function Macros

gawk - Find and Replace text within file(s)

getopts - Parse positional parameters

grep - Search file(s) for lines that match a given pattern

groups - Print group names a user is in

gzip - Compress or decompress named file(s)

hash - Remember the full pathname of a name argument

head - Output the first part of file(s)

history - Command History

hostname - Print or set system name

id - Print user and group id's

if - Conditionally perform a command

import - Capture an X server screen and save the image to file

info - Help info

install - Copy files and set attributes

join - Join lines on a common field

kill - Stop a process from running

less - Display output one screen at a time

let - Perform arithmetic on shell variables

ln - Make links between files

local - Create variables

locate - Find files

logname - Print current login name

logout - Exit a login shell

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)

m4 - Macro processor

man - Help manual

mkdir - Create new folder(s)

mkfifo - Make FIFOs (named pipes)

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

mv - Move or rename files or directories

nice - Set the priority of a command or job

nl - Number lines and write files

nohup - Run a command immune to hangups

passwd - Modify a user password

paste - Merge lines of files pathchk Check file name portability

popd - Restore the previous value of the current directory

pr - Convert text 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

pwd - Print Working Directory

quota - Display disk usage and limits

quotacheck - Scan a file system for disk usage

quotactl - Set disk quotas

ram - ram disk device

rcp - Copy files between two machines.

read - read a line from standard input

readonly - Mark variables/functions as readonly remsync Synchronize remote files via email

return - Exit a shell function

rm - Remove files

rmdir - Remove folder(s)

rpm - Remote Package Manager

rsync - Remote file copy (Synchronize file trees) screen Terminal window manager

sdiff - Merge two files interactively

sed - Stream Editor

select - Accept keyboard input

seq - Print numeric sequences

set - Manipulate shell variables and functions

shift - Shift positional parameters

shopt - Shell Options

shutdown - Shutdown or restart linux

sleep - Delay for a specified time

sort - Sort text files

source - Run commands from a file `.'

split - Split a file into fixed-size pieces

su - Substitute user identity

sum - Print a checksum for a file

symlink - Make a new name for a file

sync - Synchronize data on disk with memory

tac - Concatenate and write files in reverse

tail - Output the last part of files

tar - Tape ARchiver

tee - Redirect output to multiple files

test - Evaluate a conditional expression

time - Measure Program Resource Use

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

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

un
iq - 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)

useradd - Create new 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 Verbosely list directory contents (`ls -l -b') vdir Verbosely list directory contents (`ls -l -b')

watch - Execute/display a program periodically

wc - Print byte, word, and line counts

whereis - Report all known instances of a command

which - Locate a program file in the user's path.

while - Execute commands

who - Print all usernames currently logged in whoami Print the current user id and name (`id -un')

xargs - Execute utility, passing constructed argument list(s)

yes - Print a string until interrupted

.period - Run commands from a file