Comprehensive A‑Z Linux Command Cheat Sheet (2023)

A

access : Checks whether a program can access a specified file, useful for testing file existence.

accton : Starts or stops the accounting process or changes the accounting file.

aclocal : Generates aclocal.m4 automatically from configure.in.

acpi : Displays battery status and other ACPI information.

acpi_available : Tests whether the ACPI subsystem is available.

acpid : Provides intelligent power management by notifying user‑space programs of ACPI events.

addr2line : Converts an address to the corresponding file name and line number.

agetty : Manages physical or virtual terminals for multi‑user access.

alias : Replaces one string with another when a shell executes a command.

amixer : Command‑line mixer for ALSA sound drivers.

aplay : Command‑line audio player for ALSA.

aplaymidi : Plays standard MIDI files via ALSA MIDI ports.

apropos : Helps users find commands when they only remember keywords.

apt : High‑level CLI for package management, intended for end users.

apt-get : Command‑line tool for handling packages.

aptitude : Provides a rich interface for interacting with the package manager.

ar : Creates, modifies, and extracts files from archives.

arch : Prints the machine architecture.

arp : Manipulates the ARP cache, allowing full dumps.

aspell : Spell‑checking utility for Linux.

atd : Daemon that schedules jobs for later execution.

atrm : Removes a specified job by its job number.

atq : Lists pending jobs scheduled by at.

autoconf : Generates configuration scripts.

autoheader : Creates template header files for configure.

automake : Generates Makefile.in files following GNU standards.

autoreconf : Creates automatically buildable source code for Unix‑like systems.

autoupdate : Updates configure.in to newer Autoconf versions.

awk : Scripting language for data manipulation and report generation.

B

banner : Prints a large ASCII string to standard output.

basename : Strips directory components and suffixes, printing the file name.

batch : Reads commands from stdin or a file and executes them when the average load is below 1.5.

bc : Command‑line calculator.

bg : Moves a foreground job to the background.

biff : Mail notification system that alerts users of new mail.

bind : Sets Readline key bindings and variables.

bison : Parser generator similar to yacc.

break : Terminates for, while, or until loops.

builtin : Runs a shell builtin with arguments and returns its exit status.

bzcmp : Calls cmp on bzip2 compressed files.

bzdiff : Compares bzip2 compressed files.

bzgrep : Searches patterns inside bzip2 compressed files.

bzip2 : Compresses and decompresses files.

bzless : Views bzip2 files without reading the entire input first.

bzmore : Filters bzip2 files for CRT viewing.

C

cal : Shows a calendar for a specific month or year; defaults to the current month.

case : Preferred when multiple if/elif branches are needed on a single variable.

cat : Reads data from files and outputs their contents.

cc : Compiles C source code into an executable.

ccrypt : Command‑line tool for encrypting and decrypting data.

cd : Changes the current working directory.

cfdisk : Text‑based graphical interface for displaying or editing partition tables.

chage : Views and modifies user password expiration information.

chattr : Changes file attributes on a filesystem.

chfn : Modifies a user's full name and other details.

chgrp : Changes group ownership of files or directories.

chkconfig : Lists all available services and views or updates their run‑level settings.

chmod : Changes file access modes.

chown : Changes file owner or group.

chpasswd : Changes passwords for multiple users at once.

chroot : Changes the root directory for a process.

chrt : Manipulates real‑time attributes of processes.

chsh : Changes a user's login shell.

chvt : Switches between available TTY terminals.

cksum : Displays a CRC value, byte count, and file name.

clear : Clears the terminal screen.

cmp : Compares two files byte‑by‑byte to determine if they are identical.

col : Filters reverse line feeds; reads from stdin and writes to stdout.

colcrt : Formats text‑processor output for CRT displays.

colrm : Deletes selected columns from a file.

column : Displays file contents in columns.

comm : Compares two sorted files line‑by‑line, showing common and unique lines.

compress : Reduces file size, adding a .Z extension.

continue : Skips the current iteration of for, while, or until loops.

cp : Copies files, groups of files, or directories.

cpio : Handles archive files like *.cpio or *.tar, copying files to or from an archive.

cpp : Preprocesses source code before compilation.

cron : Schedules tasks to run automatically at specified times.

crontab : Lists scheduled tasks.

csplit : Splits a file into multiple parts based on user criteria.

ctags : Quickly accesses definitions such as function locations.

cupsd : Scheduler for CUPS, implementing Internet Printing Protocol.

curl : Transfers data to or from a server using any supported protocol.

cut : Extracts sections from each line of a file.

cvs : Stores file history and can revert to previous versions.

D

date : Displays or sets the system date and time.

dc : Evaluates arithmetic expressions in postfix notation.

dd : Converts and copies files, often used for low‑level data copying.

declare : Declares shell variables and functions, setting attributes and displaying values.

depmod : Generates dependency descriptions for kernel modules.

df : Shows total and available space information for filesystems.

diff : Displays line‑by‑line differences between files.

diff3 : Compares three files line‑by‑line.

dir : Lists directory contents.

dirname : Removes trailing slashes from a path, printing the remaining part.

dirs : Shows the list of remembered directories.

disable : Stops a printer or class.

dmesg : Checks the kernel ring buffer and prints kernel messages.

dmidecode : Retrieves hardware information such as CPU, RAM, and BIOS details.

domainname : Returns the NIS domain name of the host.

dos2unix : Converts DOS text files to UNIX format.

dosfsck : Diagnoses and attempts to fix MS‑DOS filesystem issues.

dstat : Retrieves statistics from system components like network, I/O devices, or CPU.

du : Tracks files and directories that consume excessive disk space.

dump : Backs up a filesystem to a storage device.

dumpe2fs : Prints superblock and block group information of a filesystem.

dumpkeys : Dumps the keyboard translation table.

E

echo : Displays the text/string passed as arguments.

ed : Line‑oriented text editor with a minimal interface.

egrep : Treats patterns as extended regular expressions and prints matching lines.

eject : Ejects removable media such as CD‑ROMs or floppy disks.

emacs : Simple‑interface editor without an insert mode.

enable : Starts a printer or class.

env : Prints environment variables or runs utilities in a custom environment.

eval : Executes arguments as a shell command.

ex : Line‑editing mode of the vi editor.

exec : Executes a command from within bash.

exit : Exits the current running shell.

expa : Converts tabs to spaces; reads from stdin if no file is specified.

expect : Automates interactive scripts that require user input.

export : Marks variables for export to child processes.

expr : Evaluates a given expression and displays the result.

F

factor : Prints prime factors of a given number.

fc : Lists, edits, or re‑executes previously entered shell commands.

fc-cache : Scans font directories and builds a cache for fontconfig‑using applications.

fc-list : Lists available fonts and styles, with filtering options.

fdisk : Dialog‑driven command for creating and manipulating disk partition tables.

fg : Brings a background job to the foreground.

fgrep : Searches for fixed strings in files.

file : Determines file type, reporting human‑readable or MIME types.

find : Searches for files and directories and performs subsequent actions.

finger : Provides detailed information about logged‑in users.

fmt : Formats text files for simplification and optimization.

fold : Wraps each line of input to a specified width.

for : Repeats a set of commands for each element in a list.

free : Shows total and used memory, swap, and kernel buffers.

Fun : Draws various patterns on the terminal.

function : Creates a function or method.

G

g++ : Preprocesses, compiles, assembles, and links source code to produce executables.

gawk : Pattern scanning and processing language.

gcc : GNU Compiler Collection for compiling C, C++, Objective‑C, etc.

gdb : GNU Debugger for programs written in C, C++, Ada, Fortran, and more.

getent : Retrieves entries from various system databases.

gpasswd : Manages /etc/group and /etc/gshadow.

grep : Searches files for a specific character pattern and prints matching lines.

groupadd : Creates a new user group.

groupdel : Deletes an existing group.

groupmod : Modifies an existing group.

groups : Lists groups a user belongs to.

grpck : Verifies integrity of group information.

grpconv : Converts to shadow groups.

gs : Calls Ghostscript, an interpreter for PostScript and PDF.

gunzip : Compresses or expands files.

gzexe : Compresses executable files and auto‑decompresses on execution.

gzip : Compresses files, creating a .gz file.

H

halt : Signals hardware to stop all CPU functions, leading to reboot or shutdown.

hash : Maintains a hash table of recently executed programs.

hdparm : Retrieves and modifies hard‑disk statistics, write‑cache, acoustic management, and DMA settings.

head : Prints the first N lines of input.

help : Shows information about shell built‑in commands.

hexdump : Filters and displays files or stdin in a human‑readable format.

history : Shows previously executed commands.

host : Performs DNS lookup operations.

hostid : Displays the host ID in hexadecimal.

hostname : Retrieves or sets the system's DNS or NIS domain name.

hostnamectl : Provides API to control and change the host name.

htop : Interactive real‑time system resource monitor.

hwclock : Accesses the hardware (real‑time) clock.

I

iconv : Converts text from one encoding to another.

id : Shows user and group IDs for the current or specified user.

if : Executes commands based on a condition.

ifconfig : Configures kernel‑resident network interfaces.

iftop : Network analysis tool for bandwidth statistics.

ifup : Activates a network interface.

import : Captures a screenshot of any active page and saves it as an image file.

info : Reads documentation in the info format, providing detailed command information.

insmod : Inserts a module into the kernel.

install : Copies files and sets attributes.

iostat : Monitors I/O statistics for devices and partitions.

iotop : Shows detailed disk I/O usage per process.

ip : Performs various network management tasks.

ipcrm : Removes IPC resources, cleaning up associated data structures.

ipcs : Displays information about IPC facilities the calling process can read.

iptables : Configures and maintains IPv4 Netfilter firewall tables.

iptables-save : Saves current iptables rules to a file.

iwconfig : Shows wireless parameters and statistics from /proc/net/wireless.

J

join : Joins lines of two files based on a common field.

journalctl : Views systemd, kernel, and journal logs.

K

kill : Sends signals to terminate processes.

L

last : Shows a list of all users who have logged in and out since the /var/log/wtmp file was created.

less : Views text files one screen at a time.

let : Evaluates arithmetic expressions for shell variables.

ln : Creates links between files.

locate : Finds files by name.

look : Displays lines that start with a given string.

lsblk : Shows detailed information about block devices.

lshw : Generates detailed hardware configuration information from /proc files.

lsmod : Shows the status of kernel modules.

lsof : Lists open files.

lsusb : Shows information about USB buses and connected devices.

M

mailq : Prints the mail queue.

man : Displays the manual page for any command.

md5sum : Verifies data integrity using MD5.

mkdir : Creates directories, allowing multiple at once.

modinfo : Shows information about a kernel module.

more : Views text files one screen at a time, useful for large files.

mount : Mounts a filesystem to the directory tree.

mpstat : Reports processor‑related statistics.

mv : Moves or renames files or directories.

N

nc (netcat) : Powerful network, security, or monitoring tool.

netstat : Shows network connections, routing tables, interface statistics, and more.

nmcli : Controls NetworkManager; can display device status, create, edit, activate/deactivate, and delete connections.

nslookup : Queries DNS for domain name or IP address mappings.

O

od : Converts input to various formats, defaulting to octal.

P

passwd : Changes a user account password.

paste : Horizontally merges files, separating columns with tabs.

pidof : Finds the process ID of a running program.

ping : Checks network connectivity between hosts.

pinky : Provides detailed information about logged‑in users.

pmap : Shows a process's memory map.

poweroff : Sends an ACPI signal to shut down the system.

printf : Displays formatted strings, numbers, or other data on the terminal.

ps : Lists currently running processes and their PIDs.

pwd : Prints the current working directory path.

R

ranlib : Generates an index to an archive.

rcp : Copies files between computers.

read : Reads a specified number of bytes from a file descriptor into a buffer.

readelf : Retrieves information from ELF files.

readlink : Prints the resolved symbolic link or canonical filename.

reboot : Reboots the system.

rename : Renames files using a Perl expression.

reset : Reinitializes the terminal.

restore : Restores files from a backup created with dump.

return : Exits a shell function.

rev : Reverses characters in each line.

rm : Removes files, directories, symbolic links, etc.

rmdir : Removes empty directories.

rmmod : Removes a module from the kernel.

route : Manages IP/kernel routing tables.

rsync : Synchronizes files and directories between two hosts.

S

sar : Monitors system resources such as CPU, memory, and I/O usage.

scp : Securely copies files between servers.

screen : Allows multiple shell sessions from a single SSH connection.

script : Records all terminal activity.

scriptreplay : Replays a recorded script log.

sdiff : Compares two files and writes results side‑by‑side.

sed : Finds, filters, replaces, and manipulates text.

select : Creates a numbered menu for user selection.

seq : Generates numbers from FIRST to LAST in INCREMENT steps.

setsid : Runs a program in a new session.

shift : Moves command‑line arguments left by one position.

showkey : Prints scan codes or ASCII codes for each key press.

shred : Securely deletes files from a hard drive.

shutdown : Safely shuts down the system.

sleep : Delays execution, creating a virtual job.

source : Reads and executes a file's contents in the current shell.

sort : Sorts file records in a specified order.

split : Splits a large file into smaller pieces.

ssh : Securely connects to a remote server or system.

strace : Powerful process monitoring and diagnostic tool.

stty : Changes and prints terminal line settings.

sudo : Prefix for commands that require super‑user privileges.

sum : Calculates checksums and block counts in files.

sync : Flushes caches to persistent storage.

systemctl : Checks and controls the systemd service manager.

T

tac : Concatenates and prints files in reverse order.

tail : Prints the last N lines of input.

tar : Creates or extracts archive files.

tee : Reads stdin and writes to stdout and one or more files.

time : Executes a command and prints real, user, and system CPU time.

top : Provides a dynamic real‑time view of system processes.

touch : Creates or modifies file timestamps.

tr : Translates or deletes characters.

tracepath : Traces the path to a destination, revealing MTU.

traceroute : Prints the route packets take to a host.

tree : Recursively lists directories with indentation.

tty : Displays information about the terminal.

type : Describes how a command name would be interpreted.

U

uname : Shows system information.

unexpand : Converts spaces to tabs.

uniq : Reports or filters duplicate lines in a file.

unix2dos : Converts Unix text files to DOS format.

until : Executes commands until a condition becomes true.

uptime : Shows how long the system has been running.

useradd : Adds a user account.

usermod : Modifies user attributes.

username : Retrieves the username and its configuration.

users : Shows usernames of currently logged‑in users.

userdel : Deletes a user account and related files.

V

vi : Default visual editor on Unix systems.

vmstat : Monitors performance metrics such as processes, memory, paging, block I/O, and CPU scheduling.

vnstat : Monitors network parameters like bandwidth consumption.

W

w : Shows who is logged in and what they are doing.

wall : Sends a message to all logged‑in users' terminals.

watch : Periodically executes a program, displaying full‑screen output.

wc : Counts lines, words, bytes, and characters in files.

wget : Downloads files from a server, can run in the background.

whatis : Retrieves a one‑line description from a manual page.

which : Locates the executable associated with a command by searching the PATH.

while : Repeats a set of commands as long as a condition remains true.

who : Shows information about currently logged‑in users.

whoami : Displays the current user's username.

write : Sends a line of text from one user's terminal to another's.

X

xargs : Builds and executes commands from standard input, converting input into arguments.

xdg-open : Opens a file or URL with the user's preferred application.

Y

yes : Prints a continuous stream of a given string; defaults to "y" if no string is provided.

Z

zdiff : Calls diff on gzip‑compressed files.

zdump : Prints the current time in specified time zones.

zgrep : Searches for expressions in compressed files.

zip : Compresses and packages files into a .zip archive.