apropos: Search through the Help manual pages
apt-get: Install and search for software packages
aspell: Spell checker
awk: It lets you find text and replace it
basename: Strips suffixes off files and directories
bash: GNU Bourne-Again Shell
bc: Arbitrary precision calculator language
bg: Sends to the background
break: Exit from a loop
builtin: Run a shell builtin
bzip2: Compresses or decompresses files
cal: Displays calendar
case: Perform a command conditionally
cat: Displays the content of the files after concatenation
cd: Change Directory
cfdisk: Partition table manipulator
chgrp: Changes the ownership of a group
chmod: Changes the access permissions
chown: Changes the owner and group of a file
chroot: Run a command, but with a different root directory
cksum: It displays the CRC checksum ad byte counts
clear: Clears the terminal screen
cmp: Compares two files
comm: Compares two sorted files line by line
continue: Resumes the next iteration of a particular loop
cp: Makes a copy of files to a different location
cron: Executes scheduled commands
crontab: Schedules a command that will run at a specified time
csplit: Splits a file into context-determined pieces
date: Changes the date and time
dc: Desk Calculator
ddrescue: Disk recovery tool
declare: Declares the variables and gives attributes
df: Gives the free space on your disk
diff: Prints the differences between two files
dig: Looks up the DNS
dir: Lists directory contents briefly
dirname: Changes a full pathname into just a path
dirs: Shows you the list of directories that are remembered
du: Get an estimation of the file space usage
echo: Displays message on the screen
egrep: Searches for files that have lines matching an extended expression
enable: Disable/enable bulletin shell commands
ethtool: Ethernet card settings
eval: Evaluates many commands
exec: Executes a command
exit: Exiting the shell
expand: Converts all the tabs to spaces
export: Sets an environment variable
expr: Evaluates expressions
false: Do nothing, unsuccessfully
fdformat: Perform low level format of a floppy disk
fdisk: Partition table manipulator for Linux systems
fg: Sends a task to the foreground
fgrep: Searches through files for tasks that match a string
file: Determines the file type
find: Find files that match a desired criteria
fmt: Reformats paragraph text
fold: Wraps text in order to fit a certain width
format: Formats tapes/disks
free: Reveals the memory usage
fsck: Checks the consistency of the file system and repairs it
fuser: Identifies and kills the process accessing a file
gawk: Finds text within files and replaces it
getopts: Parse positional parameters
grep: Searches in files for lines matching a certain pattern
groupadd: Adds security user groups
groupdel: Deletes a certain group
groupmod: Modifies a group
groups: Prints the names of groups in which a user is located
gzip: Compresses/decompresses files
hash: Complete pathname of a name argument
head: Outputs the first part of files
history: Command History
hostname: Print/set system name
iconv: Converts the character set in files
id: Displays the group ids/user ids
if: Conditional command
ifconfig: Configures network interfaces
ifdown: Stops a network interface
ifup: Starts a network interface app
import: Captures a screen and saves image in X server
Install: Sets attributes and copies files
jobs: Lists jobs that are active
Join: Joins lines on a common field
kill: Stops a process from running
Killall: Kills processes by name
less: Displays the output on a single screen at a time
let: Performs arithmetic on shell variables
link: Creates a link to another file
ln: Creates a symbolic link to another file
local: Creates variables
locate: Finds files
logname: Print the login name being used currently
logout: Use this command to exit a login shell.
lpc: Line Printer Control
lpr: Offline print
lprint: Prints a file
lprintd: Aborts an ongoing print job
lprintq: Lists the print queue
lprm: Removes the jobs from the print queue
make: Recompiles the group of programs
man: Provides help on a command
mkdir: Creates directories
mkfifo: Makes FIFOs
mknod: Creates character special files or block files
more: Displays the output in a single screen at a time
mount: Mounts a particular filesystem
mtools: Manipulates files from MS-DOS
mtr: Network diagnostics command
mv: Moves and renames files and directories
mmv: Mass Move and Rename
netstat: Provides information on networking
nice: Sets the priority of a job or a command
nl: Writes files and number lines
nohup: Runs a command not affected by hangups
notify-send: Sends desktop notifications
nslookup: Queries internet name servers interactively
open: Opens a file in its default application
op: Provides operator access
passwd: Modifies user passwords
paste: Merges lines in files
pathchk: Checks the portability of a file name
ping: Tests network connections
pkill: Stops processes from running
popd: Restores the previous value of the directory you’re currently in
pr: Prepares your files for printing
printcap: Printer capability database
printenv: Print environment variables
printf: Formats and prints data
ps: Process Status
pushd: Changes the directory and saves it first
pwd: Print Working Directory
quota: Displays the disk usage and its limits
quotacheck: Lets you scan a file system to find its disk usage
quotactl: Sets disk quotas
ram: Ram disk device
rcp: Copies files between two devices.
read: Reads a line from standard input
readarray: Reads from stdin into an array variable
readonly: Marks the variables and functions as readonly
reboot: Reboots your system
rename: Renames files
renice: Alters the priority of the processes running
remsync: Synchronises remote files through email
rev: Reverses the lines in a file
rm: Removes particular files
rsync: Synchronises file trees
screen: Run remote shells using ssh
scp: Creates a secure copy
sdiff: Merges two files in a secure manner
sed: Stream editor
select: Accepts keyboard inputs
seq: Prints numeric sequences
set: Manipulates shell functions and variables
sftp: Runs the secure file transfer program
shift: Shifts positional parameters
shopt: Shell Options
shutdown: Shuts down Linux or restarts it
sleep: Adds a delay
slocate: Finds particular files
sort: Sorts text files
source: Runs commands from a file
split: Breaks a file into fixed sizes
ssh: Runs the remote login program
strace: Traces signals and system calls
su: Substitutes the user identity
sudo: Executes commands as a different user
suspend: Suspends the execution of the current shell
sync: Synchronises data from a disk with the memory
tail: Outputs only the last part of a file
tar: Stores a list or extracts files in an archive
tee: Redirects output into multiple files
test: Evaluates conditional expressions
time: Measures the running time of a program
timeout: Puts a time limit on a command
times: Finds the user and system times
touch: Changes timestamps on a file
traceroute: Trace Route to a host
tr: Deletes characters, translates or squeezes them
tsort: Topological sorting
ulimit: Limits the user resources
umask: Determines the file permission for a new file
umount: Unmounts a device from the system
unalias: Removes an alias
uname: Prints the system information
unexpand: Converts the spaces in a file to tabs
uniq: Uniquify your files
units: Converts the units from one scale to another
unset: Removes the variable names or the function names
unshar: Unpacks the shell archive scripts
until: Executes a command until there is an error
uptime: Shows the uptime
usermod: Modifies a user account
users: Gives you a list of users who are currently logged in
uuencode: Encodes binary files
v: Lists the contents of a directory
vi: Text editor
vmstat: Reports on the virtual memory statistics
wait: Directs the system to wait for a process to finish
watch: Displays or executes a program periodically
wc: Prints the word, byte and line counts
while: Executes commands
who: Prints the usernames that are currently logged into the system
whoami: Prints the current name and user id
wget: Retrieves the web pages or files through HTTP, HTTPS or FTP
write: Sends messages to other users
xargs: Executes a utility and passes a constructed argument list
xdg-open: Opens a URL or a file in the user's preferred application
yes: Prints a string until it is interrupted
