An A-Z Index of the Linux BASH command line

 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

  bind     Set or display readline key and function bindings 

  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

  chattr   Change file attributes on a Linux file system 

  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

  curl     Transfer data  from or to a server

  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

  htop     Interactive process viewer

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

  iostat   Report CPU and i/o statistics

  ip       Routing, devices and tunnels

j

  jobs     List active jobs

  join     Join lines on a common field

k

  kill     Kill a process by specifying its PID

  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 a function variable 

  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

  lsattr   List file attributes on a Linux second extended file system

  lsblk    List block devices

  ls       List information about file(s)

  lsof     List open files

  lspci    List all PCI devices

m

  make     Recompile a group of programs

  man      Help manual

  mkdir    Create new folder(s)

  mkfifo   Make FIFOs (named pipes)

  mkfile   Make a file

  mkisofs  Create an hybrid ISO9660/JOLIET/HFS filesystem

  mknod    Make block or character special files

  mktemp   Make a temporary file

  more     Display output one screen at a time

  most     Browse or page through a text file

  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

  nc       Netcat, read and write data across networks

  netstat  Networking connections/stats

  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

  pgrep    List processes by name

  pkill    Kill processes by name

  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

r

  ram      ram disk device

  rar      Archive files with compression

  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

  ss       Socket Statistics

  ssh      Secure Shell client (remote login program)

  stat     Display file or file system status 

  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

  tput     Set terminal-dependent capabilities, color, position

  traceroute Trace Route to Host

  trap      Execute a command when the shell receives a signal

  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

  unrar    Extract files from a rar archive 

  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

  w        Show who is logged on and what they are doing

  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

  xz       Compress or decompress .xz and .lzma files

y

   yes       Print a string until interrupted

z

   zip      Package and compress (archive) files

   .         Run a command script in the current shell

   !!        Run the last command again

   ###      Comment / Remark