Navigation

pwd: Print name of current working directory

cd: Change directory

ls: List directory contents

Exploring the System

file: View a brief description of the file contents

less: View file contents

Manipulating Files and Directories

cp: Copy files and directories

mv: Move/rename files and directories

mkdir: Create directories

rm: Remove files and directories

ln: Create hard and symbolic links

Working with Commands

type: Indicate how a command name is interpreted

which: Display which executable program will be executed

help: Get help for shell builtins

man: Display a command’s manual page

apropos: Display a list of appropriate commands

info: Display a command’s info entry

whatis: Display one-line manual page descriptions

alias: Create an alias for a command

Redirection

cat: Concatenate files

sort: Sort lines of text

uniq: Report or omit repeated lines

grep: Print lines matching a pattern

wc: Print newline, word, and byte counts for each file

head: Output the first part of a file

tail: Output the last part of a file

tee: Read from standard input and write to standard output and files

Seeing the World as the Shell Sees It

echo: Display a line of text

Advanced Keyboard Tricks

clear: Clear the screen

history: Display the contents of the history list

Permissions

id: Display user identity

chmod: Change a file’s mode

umask: Set the default file permissions

su: Run a shell as another user

sudo: Execute a command as another user

chown: Change a file’s owner

chgrp: Change a file’s group ownership

passwd: Change a user’s password

Processes

ps: Report a snapshot of current processes

top: Display tasks

jobs: List active jobs

bg: Place a job in the background

fg: Place a job in the foreground

kill: Send a signal to a process

killall: Kill processes by name

shutdown: Shutdown or reboot the system

The Environment

printenv: Print part or all of the environment

set: Set shell options

export: Export environment to subsequently executed programs

alias: Create an alias for a command

Storage Media

mount: Mount a file system

umount: Unmount a file system

fsck: Check and repair a file system

fdisk: Manipulate disk partition table

mkfs: Create a file system

dd: Convert and copy a file

genisoimage (mkisofs): Create an ISO 9660 image file

wodim (cdrecord): Write data to optical storage media

md5sum: Calculate an MD5 checksum

Networking

ping: Send an ICMP ECHO_REQUEST to network hosts

traceroute: Print the route packets trace to a network host

ip: Show / manipulate routing, devices, policy routing and tunnels

netstat: Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

ftp: Internet file transfer program

wget: Non-interactive network downloader

ssh: OpenSSH SSH client (remote login program)

Searching for Files

locate: Find files by name

find: Search for files in a directory hierarchy

xargs: Build and execute command lines from standard input

touch: Change file times

stat: Display file or file system status

Archiving and Backup

gzip: Compress or expand files

bzip2: A block sorting file compressor

tar: Tape archiving utility

zip: Package and compress files

rsync: Remote file and directory synchronization

Text Processing

cat: Concatenate files and print on the standard output

sort: Sort lines of text files

uniq: Report or omit repeated lines

cut: Remove sections from each line of files

paste: Merge lines of files

join: Join lines of two files on a common field

comm: Compare two sorted files line by line

diff: Compare files line by line

patch: Apply a diff file to an original

tr: Translate or delete characters

sed: Stream editor for filtering and transforming text

aspell: Interactive spell checker

Formatting Output

nl: Number lines

fold: Wrap each line to a specified length

fmt: A simple text formatter

pr: Prepare text for printing

printf: Format and print data

groff: A document formatting system

Printing

pr: Convert text files for printing

lpr: Print files

a2ps: Format files for printing on a PostScript printer

lpstat: Show printer status information

lpq: Show printer queue status

lprm: Cancel print jobs

Compiling Programs

make: Utility to maintain programs

Reference:

Shotts, William. The Linux command line: a complete introduction. No Starch Press, 2019.