Linux Ubuntu Commands Cheat Sheet

 

System Information Ubuntu Commands

System information commands in Ubuntu enable users to retrieve important information about their system such as user information, CPU usage, etc. See the table containing system information command lists below:

Commands	Description
free	Displays the amount of free and used memory in the system
ps	Displays a snapshot of the current processes
ps aux	Displays detailed information about all processes currently running
uptime	Displays the current uptime of the system
w	Displays the list of currently logged-in users
uname	Displays system information
uname -a	Displays detailed system information
hostname	Displays the name of the current host
info	Provides access to the documentation of various installed software packages
lshw	Lists hardware configuration of the system
history	Displays a list of previously executed commands
help	Displays information about built-in shell commands
man	Displays the manual page for a specified command
tty	Reports the file name of the terminal device that is currently used to interact with the shell

System Administration Ubuntu Commands

In this section, I have listed system administration Ubuntu commands that you can use to monitor system performance, install and update software, and other administrative tasks. Check out the following table:

Commands	Description
sudo	Allows users to run programs with the security privileges of another user, typically the root user
sudo -s	Starts a shell with root privileges
sudo -s -u -user	Starts a shell with the privileges of the specified user
sudo -k	Invalidates the user’s cached credentials
sudo visudo	Opens the sudoers file for editing
sudo -H nautilus	Opens the file browser with root privileges
sudo  /etc/init.d/gdm restart	Restarts the GDM (GNOME Display Manager) service
sudo /etc/init.d/kdm restart	Restarts the KDM (KDE Display Manager) service
passwd	Allows users to change their password
shutdown	Shuts down the system in a safe way
sync	Forces all file system changes to be written to disk
reboot	Reboots the system
install	Installs one or more packages on a Linux system using a package manager
setstatus	Displays the status of the SELinux security system
service	Controls system services, such as starting, stopping, and restarting them
getent	Retrieves entries from databases
env	Displays the current environment variables or sets a new environment variable
jobs	Displays a list of jobs running in the background of a shell

Permission Management Ubuntu Commands

In this section, I’ve listed the commands you’ll need to change access permissions and perform other system administration tasks:

Commands	Description
chmod	Changes the permissions of a file or directory and determines who can read, write, or execute a file
chown	Changes the owner and/or group of a file or directory

System Monitoring Ubuntu Commands

This category contains system monitoring Ubuntu commands that allow users to monitor system performance and provide real-time information on system resource usage and process activity. To check the system monitoring Linux commands, go through the below table:

Commands	Description
top	Displays information about the active processes running on the system
htop	Shows a list of all the running processes throughout the system
vmstat	Shows detailed information about system performance, including memory usage, CPU utilization, and Input/Output (I/O) statistics
free	Displays the total amount of free and used memory in the system, as well as the buffers and cached memory used by the kernel
ps	Displays information about the active processes on the system, including their process ID (PID), CPU usage, memory usage, and other details
uptime	Displays how long the system has been running and the current system load averages
time	Measures the execution time of a command or script
dmesg	Displays the kernel ring buffer messages, which include system boot messages and other kernel-related messages
finger	Displays information about a user, including their login name, full name, home directory, login shell, and the time they last logged in

Shell Built-in Ubuntu Commands

The shell directly executes some commands. Here, you can find these commands without the use of an external program. Following are the shell built-in Linux commands:

Commands	Description
export	Sets environment variables that are used by processes started by the shell that exported the variable
echo	Displays text on the screen or redirects it to a file or variable
alias	Creates a shortcut or alternate name for a command
unalias	Removes an alias previously created with the “alias” command.
exit	Closes the current shell or terminal session
clear	Clears the terminal screen
bash	Enables users to interact with Linux Operating System
declare	Declares variables and specifies their attributes, such as their data type or scope
source	Executes a script in the current shell environment rather than creating a new subshell to run the script

File and Directory Management Ubuntu Commands

You can use the file and directory management Ubuntu commands to manage and manipulate files and directories, such as copying, removing, searching, and navigating through them. Get the list in a tabular form below:

Commands	Description
mkdir	Creates a new directory
cd	Changes the current working directory to a specified directory
cd ..	Changes the current working directory to the parent directory of the current directory
pwd	Prints the current working directory
rm [file]	Removes a file
rm -r [dir]	Removes a directory and its contents
rm -f [file]	Forces the removal of a file
rm -rf [dir]	Forces the removal of a directory and its contents
mv	Moves or renames files or directories
cp	Copies files or directories
locate	Searches for files in a database that contains a cached record of all files on the system
cmp	Compares two files byte-by-byte and reports the first byte and line that differs between them
comm	Compares two sorted files line by line and displays the lines that are common or unique to each file
lsof	Lists all open files and the processes that opened them
chgrp	Changes the group ownership of files and directories
file	Determines the type of a file by examining its contents
fsck	Checks and repairs a file system for errors
patch	Applies a patch file to an original file, making the changes specified in the patch file
stat	Displays detailed information about a file, including its size, permissions, owner, and modification time

File Management and Manipulation Ubuntu Commands

You’ll find commands in this category that allow users to manage and manipulate files and directories, such as creating, listing, and comparing files and directories, making it simple to organize and work with files on your Linux system. For example:

Commands	Description
ls	Lists files in a directory
ls -al	Lists all files in a directory, including hidden files, with detailed information.
ls -R	Lists files in a directory and all of its subdirectories
ls -a	Lists all files in a directory, including hidden files
touch	Modifies timestamps of a file or creates an empty file if it doesn’t exist
diff	Compares two files line by line and shows the differences between them

Compression and Archiving Ubuntu Commands

This category contains commands that enable users to compress, decompress, and archive files:

Commands	Description
zip	Archives files and directories into a compressed zip archive format
unzip	Extract the contents of a zip archive file
bzip2	Compresses files using the Burrows-Wheeler block sorting text compression algorithm and Huffman coding
gzip	Compresses files using the Lempel-Ziv algorithm and Huffman coding
gunzip	Decompresses files that have been compressed using gzip
tar	Creates and manipulates archive files

Package Management Commands in Ubuntu

These commands allow users to manage software packages by installing, removing, updating, and searching for packages:

Commands	Description
apt-get update	Updates the list of available packages
apt-get upgrade	Upgrades all installed packages to their latest version
apt-get dist-upgrade	Upgrades all installed packages to their latest version
apt-get install pkg	Installs a package
apt-get purge pkg	Completely removes a package, including its configuration files
apt-get autoremove	Removes any packages that were installed as dependencies and are no longer needed
apt-get -f install	Attempts to fix any broken dependencies and install missing packages
dpkg -l	Lists all installed packages
dpkg – -configure -a	Configures all packages that have been unpacked but not yet configured
dpkg -i pkg.deb	Installs a package from a .deb file
snap	Installs and manages applications on systems

Network Configuration and Firewall Management Commands

In this category, you’ll find commands for configuring and managing network interfaces and firewall rules in the Linux operating system:

Commands	Description
wget	Downloads files from the internet
ifconfig	Shows network interface configuration
iwconfig	Shows wireless network interface configuration
sudo iwlist scan	Scans for available wireless networks
sudo systemctl restart networking.service	Restarts the networking service
ifup interface	Brings up a network interface
ifdown interface	Brings down a network interface
firewall -cmd	Allows users to configure and manage the firewall settings
ufw enable	Enables the firewall
ufw disable	Disables the firewall
ufw default allow	Sets the default policy to allow traffic
ufw default deny	Sets the default policy to deny traffic
ufw status	Shows the status of the firewall
ufw allow port	Opens a port
ufw deny port	Closes a port
ufw deny from ip	Blocks traffic from a specific IP address

Network Management Ubuntu Commands

These commands allow users to manage network connections, display network information, and troubleshoot network issues:

Commands	Description
ip	Displays and manipulates network interfaces and routing tables
ping	Sends a packet to a host and measures the response time
ssh	Remotely logs into a server or other device over a network
scp	Transfers files between hosts on a network

User Management Ubuntu Commands

You can use user management commands to manage user accounts and permissions, such as creating, modifying, and deleting user accounts, managing user groups, and setting permissions on files and directories, all of which contribute to the security and accessibility of the system. The table containing user management Linux commands is given below:

Commands	Description
useradd	Creates a new user account, including setting up a home directory and assigning a password
adduser	Creates a new user account interactively or using command-line options
who	Displays information about the users who are currently logged in
whoami	Displays the current username of the user who is logged in
id	Displays the user and group IDs of a specified user or the current user
usermod	Modifies a user account, such as changing the user’s login name, password, home directory, or group membership
users	Displays a list of usernames of users who are currently logged in
su	Switches the current user to another user account, usually with elevated privileges, by prompting for the target user’s password
chage	Modifies the password expiry information for a user
userdel	Deletes a user account and all associated files and directories
addgroup	Creates a new user group
groupadd	Creates a new user group
groupmod	Modifies the properties of an existing user group

Disk Management Commands in Ubuntu

In this section, you’ll find commands for displaying disk usage, as well as creating, resizing, and formatting disk partitions, as well as mounting and unmounting file systems, to help you optimize storage usage and maintain the health of your Linux system’s storage. Check the table below:

Commands	Description
df	Displays the disk usage statistics for the file system
df -h	Displays the disk usage statistics for the file system in human-readable format
du	Estimates the file space usage
fdisk	Allows users to create, delete, and modify partitions on hard drives, flash drives, and other storage devices
shred	Securely deletes files by overwriting them multiple times with random data
dd	Copies and converts data between files, partitions, and devices at the block level
mount	Mounts a file system, making it accessible at a specified mount point in the directory tree
mke2fs	Creates a new ext2/ext3/ext4 file system on a specified device
mkfs	Creates a new file system on a specified device and supports various file system types such as ext2, ext3, ext4, NTFS, and FAT32

Text Processing Ubuntu Commands

In this section, I’ve listed commands for editing, searching, sorting, and transforming text to help you work with large text files and automate text processing tasks:

Commands	Description
wc	Counts the number of lines, words, and characters in a text file
sort	Sorts the lines of a text file in alphabetical or numerical order
nano	Allows users to create and edit text files
cut	Extracts specific columns or fields from a text file
jed	Opens up a powerful text editor that supports multiple modes and macros
vi	Opens up a powerful text editor that uses modal editing to allow for quick and efficient editing
vim	Opens up a more advanced version of the vi editor with additional features such as syntax highlighting and plugins
paste	Merges lines from multiple files and writes them to the standard output
egrep	Searches a text file for lines that match a specified pattern using extended regular expressions
split	Splits a text file into smaller files based on the number of lines or bytes
sed	A stream editor that performs editing operations on a text stream or file
tr	Translates or deletes characters in a text stream or file
uniq	Filters out duplicate lines from a sorted text file
cat	Displays the contents of a file on the terminal
head	Displays the first ten lines of a file on the terminal
tail	Displays the last ten lines of a file
grep	Searches for a specific pattern or text in a file or output
less	Displays the contents of a file one page at a time, allowing scrolling back and forth.
more	Display the contents of a text file one screen at a time allowing user to scroll up and down through the file, search for specific text, and navigate to specific lines

Miscellaneous Commands in Ubuntu

This section contains commands that provide additional functionality and utility, such as task scheduling, time and calendar display, and so on:

Commands	Description
lsblk	Lists information about all available or specified block devices and can also display the relationship between the different devices, such as partitions and logical volumes
enable	Enables or disables a service at startup or a specific hardware device or driver
bc	Command-line calculator that allows for floating-point arithmetic and advanced mathematical functions
cron	Automates tasks to run at specified times or intervals
crontab	Schedules periodic commands or scripts to run at specified intervals
ncal	Displays a calendar for a given month or year
neofetch	Displays system information and an ASCII art logo of the operating system
tree	Displays a directory tree structure in a hierarchical forma
whereis	Locates the binary, source, and manual page files for a command
whatis	Displays a brief description of a command
which	Displays the location of a command or script in the system’s PATH
at	Schedules a one-time command or script to run at a specified time
tee	Redirects the output of a command to a file and to the screen
date	Displays the current date and time

Ubuntu Keyboard Shortcuts

In this section, you will find some keyboard shortcuts for Ubuntu. Using these shortcuts can help you save time on your tasks:

Commands	Description
CTRL+ALT+T	Opens terminal in Ubuntu
CTRL+A	Places the cursor at the start of the active line
CTRL+E	Places the cursor at the end of the active line.
CTRL+U	Removes the entire active line
CTRL+K	Removes the command from the cursor to the right
CTRL+W	Removes the word preceding the cursor.
CTRL+R	Performs a history search for commands that match the user’s input
CTRL+C	Stop the active process
CTRL+ D	Closes the current terminal
CTRL+Z	Sends the signal SIGSTOP to temporarily halt the active process
CTRL+L	Clears terminal display
CTRL+Q	Resumes suspended commands
CTRL+S	Halts command output to the screen
CTRL+Z	Halts the current command and places it in the background
CTRL+G	Exits the history search mode.
CTRL+J	Completes the history search at the current command line.
CTRL+O	Executes the command found in the reverse search.
CTRL+N / Down Arrow	Displays the following command line
CTRL+P / Up Arrow	Displays the preceding command line
CTRL+ _	Undo the last action
ALT+F	Goes forward one word
ALT+B	Goes back one word
ALT+P	Searches the history forward from the current line
CTRL+SHIFT+T	Opens a new tab on the currently active terminal.
CTRL+SHIFT+W	Closes the active tab
CTRL+SHIFT+C	Copies the highlighted characters to the clipboard
CTRL+SHIFT+V or SHIFT+INSERT	Pastes contents of the clipboard to the active line
Up/Down Arrow keys	Allows to quickly execute previous commands multiple times
TAB	Completes the typing command
CTRL+B / Left Arrow	Moves cursor position one character backward
CTRL+F / Right Arrow	Moves cursor position one character forward
CTRL+XX	Switches between the current cursor position and the start line
CTRL+]+A	Moves the cursor forward to next character of A
ALT+CTRL+]+A	Backs the cursor to the preceding character of A