Top 50+ Essential Linux Commands You Should Know
Mar. 1, 2023Linux is a popular open-source operating system that’s used in a variety of fields such as software development, server administration, and cybersecurity. While Linux has a graphical user interface (GUI), it also includes a powerful command line interface. With the popularity ofSteam Deckof recent, everyone wants to learn more about Linux and its CLI, the Terminal. The Terminal may appear intimidating to many users, but it is a powerful tool that lets you do a plethora of tasks with ease. In this article, we will look at some of the most important Linux Terminal commands that every user should know.
We have covered commands for everything, ranging from basic file and directory management to more complex tasks like networking and system administration. Whether you are a novice or a seasoned Linux user, it’s time to open the Terminal and try out these commands.
Basic Help Commands
This command is going to be your savior whenever you need to know what a command does and all its options. It stands for “manual” and is used to show the help menu for any command along with its syntax and options to use.
The syntax to use the command is:
man
Sometimes, you might want to know the location of an executable command. Thewhichcommand returns the path of any program’s executable file on the system. It returns the path where the command is installed. The syntax to use the command is:
which <command_name>
Thewhereiscommand works similarly to thewhichcommand, except it provides the path for the executable, the source code and the man page. The syntax to use the command is:
whereis <command_name>
This command is used to print the system information like the operating system name, kernel name, etc. The syntax to use the command is:
uname
If you ever see an error “Permission Denied”, thesudocommand can help you in executing commands as the “superuser,” also known as the “root user”. It is advisable not to run a command withsudoprivileges always, as it can do some serious damage to the system.sudocan only work as the superuser if you have privileges to run the command as the root user. The syntax to use the command is:
sudo <command_name>
sshstands for “Secure SHell” and is used to connect to a remote host system using the ssh protocol. The syntax to use the command is:
ssh @<host_ip_address_or_domain_name>
There may be times when you need to switch to another user. This can be done using the su command which stands for “switch user”. The syntax to use the command is:
su
Once you execute this command, this will prompt you for a password and start a new shell/session for the new user.
Thewhocommand is particularly helpful inside a multi-user system and is used to show information such as the name of the user who’s currently logged in, last boot time, etc. The syntax to use thewhocommand is:
who
Generally, thewhocommand is used without any options, but the most common option used with the command is-a, which shows all the users logged in and their boot times.
Thewhoamicommand is used to show the current user who is logged in into the system. The syntax to use the command is:
whoami
If you ever need to add a new user to your system, use theuseraddor theaddusercommands. Theaddusercommand is a symbolic link to theuseraddcommand. These commands add a new user to the system and is very useful in the case of a multi-user environment. To execute the command, use the following syntax:
useradd -d <user_home_directory>
This command works similarly to the useradd command, except it modifies an existing user. It can modify groups, permission, etc for any existing user. The syntax to use the command is:
usermod <permission_set>
Much like you can modify the user permissions using the usermod command similarly, you can also modify the password for the current user using thepasswdcommand. Or, if you are the superuser, you can also change the password for other users using the same command. To change the password for the current user, run the commandpasswd, type the old password and then type the new password twice and hit enter.
Syntax ofpasswdcommand is as follows:
passwd
If you ever get lost in the Linux filesystem, run thepwdcommand. It stands for “print working directory” and as the name suggests, it shows your current position in the entire file system. The syntax to run the command is:
pwd
The ls command is used to show the contents of any directory specified, if the user has read permission. By default, it shows the contents of the current directory if no other parameter is specified. It is one of the most useful commands in Linux. The syntax to use the ls command is:
ls <directory_name>
This command is used to switch to a different directory from the current one. The syntax to use the command is:
cd <directory_name>
If the command is used without any arguments, it will redirect you to the home directory, i.e./home//
There are two types of paths which can be used with this command:
This command creates the directory(ies) if they do not already exist in the specified path. The syntax to create a new directory usingmkdiris:
mkdir <directory_name>
You can also use both absolute and relative paths to specify the directory name while creating a new sub-directory inside a different directory.
Generally, this command is used to delete empty directories, but can also remove directories with content using some special flags. The syntax to use this command is:
rmdir <directory_name>
This command is more versatile than thermdiras it can remove both folders as well as files and also has many options to work with. The syntax to use the rm command is:
rm <file_or_directory_name>
This command works the same as the COPY-PASTE in Windows and is used to make copies of files and directories and store them in the specified directory. The syntax to use the command is:
cp <original_file_path> <copied_file_path>
Themvcommand works the same as the CUT – PASTE in Windows and is used to move a file or directory into a different directory. The syntax to use the mv command is:
mv <source_file> <destination_file>
The links in Linux are similar to shortcuts in windows. To create a link in Linux, use the ln command as per the syntax shown below:
ln -s <source_path> <link_name>
Here, the-sflag is used to create a soft link. Soft links can be used to link to anything in a system including directories, file systems, etc. Any changes made to the original file are not reflected in the linked file.
If the-sflag is not used, a hard link will be created which has numerous limitations, such as you cannot link directories, file systems, etc. Any changes made to the hard-linked file will be reflected in the original file also.
This command is used to open any file or directory from the terminal with the default application selected. The syntax to use the command is:
xdg-open <file_directory_name>
The tar command stands for “tape archive” and is used to combine multiple files into a single archive file. It is one of the most important commands in Linux and can be used to both compress and decompress files. The archive file thus formed is with the extension .tar. The syntax to use thetarcommand is:
tar <archive_file> <file_or_directory_to_be_archived>
The zip command is used to compress a set of files and directories into a .zip archive file without losing the quality. The syntax to use the zip command is:
zip <file_1> <file_2>
The unzip command is used to extract .zip files. The syntax to use the unzip command is:
unzip <zip_file>
The gzip command works similarly to the zip command, except it has a higher compression rate and creates smaller archive files. The archive files are created with .gz file extension. The syntax to use the gzip command is:
gzip <file_1> <file_2>
To extract .gz files, use thegunzipcommand. It works similarly to the unzip command, except it takes more time to extract as it has a higher compression rate. The syntax to use thegunzipthe command is:
gunzip <archive_file>
In Linux, everything is treated as a file, even storage devices and file systems also. Themountcommand is quite useful as it can help in mounting various types of storage devices and file systems with the default mount location as/etc/fstab. The standard form of themountcommand is:
mount -t <path_to_mount>
To remove a file system or a storage device from the system, use theumountcommand. The syntax to use theumountcommand:
umount <path_of_device>
At times, you must have seen the annoying error message for lack of storage but can never find the file which is occupying the most disk space. For such a situation, you should use the du command which can help to monitor the files occupying the most disk space and further reveal some internal problems. The basic syntax to use theducommand is:
du <file_or_directory>
This command works similarly to theducommand, except it shows you the complete summary of the total available space in the file system. The syntax to use thedfcommand is:
df
The common options which you can use are:
Thewgetcommand is used to download files from the internet using various protocols like HTTP, HTTPS, FTPS, etc. The basic syntax to use thewgetcommand is:
wget <url_of_file>
Thecatcommand is used to print the entire contents of any given file(s). To view the contents of any number of files, use the following syntax:
cat
This command works similarly to thecatcommand, except it prints the contents of a file in ascending order. The syntax to use thesortcommand is:
sort <file_name>
This command removes the duplicate lines from the file’s contents or from another command’s output. The syntax to use theuniqcommand is:
uniq <file_name>
Thewccommand stands for word count. It can count the total number of words, characters, number of lines, etc. The syntax to use the command is:
wc <file_name>
This is probably one of the most important Linux commands and is used by every Linux user. Thechmodcommand is used to modify the permissions for a particular file or directory. The syntax to use the command is:
chmod <permission_set> <file_or_directory>
There are 3 types of permissions you can specify, using the permission set:
read: Allows the users to view the contents of a file or directory, abbreviated as ‘r’.
write: Allows the users to make changes to the file or directory abbreviated as ‘w’.
execute: Allows the users to execute a file abbreviated as ‘x’.
This command works similarly tochmod, except it changes the file owner by modifying the user group. Only the owner and the root user can change the file ownership. The syntax to use this command is:
chown
In Linux, if you ever need to compare two files, there are three commands to use –diff,cmp, andcomm. Thediffcommand displays the differences in two files line by line. The syntax to use thediffcommand is:
diff <file_1> <file_2>
Thecmpcommand works similarly to thediffcommand except it compares the two files byte-wise. If the command finds any disparity between two files, then it returns the first location of the disparity. The syntax to use thecmpcommand is:
cmp <file_1> <file_2>
Thecommcommand combines the output of both thediffand thecmpcommands. It shows both line-by-line comparison as well as the byte-wise comparison. The syntax to use the command is:
comm <file_1> <file_2>
Suppose you have a very large file like an access log file and want to see the first entries or the latest entries in it. You can always use thecatcommand to print out the file contents but it can become very cumbersome to scroll through thousands of lines. In such a situation, you can use either theheadcommand or thetailcommand. Theheadcommand will print the first 10 lines of the file by default, and thetailcommand will print the last 10 lines of the file, making it easier to see the desired lines. The syntax to use theheadcommand is:
head <file_1> <file_2>
The syntax to use thetailcommand is:
tail <file_1> <file_2>
As we said above, viewing the contents of a large file like a log file viacatcommand is not the best way as it may take a pretty long time to print the contents. Here,lesscommand will be your saviour as it will show the file contents without cluttering the terminal screen and it also works much faster than thecatcommand or any other text editors. It also has syntax highlighting and scrolling using the arrow keys or the page up/down keys. The syntax to use thelesscommand is:
less <filename_1> <filename_2> <filename_3>
To exit out of thelessview, press the “q” key.
This command is useful if you want to create multiple empty files quickly. You can also use thetouchcommand to change the access time of a file in the logs. The syntax to use thetouchcommand is:
touch <file_name>
These text editors have a variety of use cases like creating new files, searching for content inside files, viewing file content, etc. apart from editing files. The nano command-line text editor is the easiest text editor for any beginner to use. When you open any file in nano, you can straight away start making changes. All other shortcuts are mentioned below in the bottom pane. To open any file using the nano text editor, use the following syntax:
nano <file_name>
If the file does not exist, an empty file will be created, else the existing file will be opened in the editor.
The vi text editor has a relatively steep learning curve. It has several modes which tend to confuse new users. To open a file using the vi text editor, use the following syntax:
vi <file_name>
This will open the file in default mode. To make any changes, press “i” on the keyboard. This will change to INSERT mode. To save the changes made and exit out of vi, first press ESC on the keyboard and then press “ZZ”.
At times you need to work on a file, but you don’t know where it is located in the entire file system. To search for files in the system, you can either use thefindcommand or thelocatecommand. Thefindcommand has more options but takes more time to search for the query. The syntax to use thefindcommand is:
find
Thelocatecommand does not have many features but works very fast as it indexes every file and folder inside a database. The syntax to use thelocatecommand is:
locate
grepis one of the most important commands for Linux. It stands for “Global Regular Expression Print”. It helps to search for a particular string based on a pattern. The command uses both regular expressions as well as normal strings to search inside files or another command’s output. The syntax to use thegrepcommand:
grep <file_name>
This command shows the list of running user processes in the system for the current user or for other users. By default, it shows the current running process id, terminal ID, status, running time, and command name. The syntax to use the command is:
ps
Thetopand thehtopcommands work similarly to the ps command, with the difference being they display more information such as CPU utilization, memory usage, etc., which gets updated in real-time. You can use thetopandhtopcommands tokill a process in Linux. The top command can be viewed as aCLI version of the Windows Task Manager. The syntax to use the command is:
top
Thehtopis similar to the top command, except it has more features and a user-friendly console but it does not come preinstalled. To installhtopon Debian-based systems, use the following command:
sudo apt install htop
To use thehtopconsole, typehtopin the terminal and pressenteron the keyboard. To exit out of eithertoporhtopconsole, pressqon the keyboard.
There may be times when some program is not working properly or freezing the system by consuming a ton of system resources. In such a situation, the best solution is to terminate the process. To kill a process, use thekillor thekillallcommands. Both commands work the same. However, there are certain differences.killtakes the process id of the process you want to terminate, which you can fetch either from ps or top command, Whereas, thekillallcommand outputs all the processes running with the name given as input. The syntax to use these commands is:
sudo kill <process_id>
sudo killall <process_name>
If you have executed a really big combination of commands and want to execute it again but can’t remember what you used, there’s a command for it. To see a list of commands you have already executed, use thehistorycommand. Thehistorycommand stores generally a list of 500 commands. The syntax to use the command is:
history
To execute a command from the history list, use the syntax:
!<serial_number>
In Linux, processes that are currently managed by the shell and have not yet finished execution are known as “jobs” and are assigned a unique sequence number to identify them. If you use the ampersand symbol “&” along with any command, the job will run in the background and will not occupy the terminal window. Such a job is known as a “Background Job”.
If you run the command without the ampersand symbol, then the job will execute in the foreground and will occupy the terminal window. Such a job is known as a “Foreground Job”. To see all the running jobs in your system, use thejobscommand. This will list all the jobs along with their job IDs. The syntax to use the command is:
jobs <job_id>
To place a job in the background and assign the status of “running” until it finishes execution, use the following syntax:
bg % <job_id>
To bring back a running background job, use the following syntax:
fg % <job_id>
Theexportcommand is used to create and view all the environment variables. To create environment variables with the export command, use the following syntax:
export <variable_name>=
The environment variables so created are temporary in nature and get removed as soon as you reboot the system. To permanently create environment variables, add the above command to the.bashrcfile using any text editor of your choice.
The crontab command is an actual boon for Linux users as it can run any task automatically periodically. Any task which runs at specific time intervals by thecrontabcommand is known as cronjobs. This command can be very useful for taking backups or cleaning the system, etc. To use thecrontabcommand, use the following syntax:
crontab
When you use the crontab -e command, it opens the default text editor to edit the current crontab. The syntax to schedule a task using the command is:
<date_of_month> <day_of_week>
A service is a program or an application that runs in the background. To manage such background services in Linux, you need to use theservicecommand, as shown in the syntax:
service <service_name>
This command is often overlooked but a very essential command in Linux. After running many different commands, the terminal screen may feel cluttered. To clear the screen of all the command outputs, use theclearcommand as shown below:
clear
You can also the shortcut CTRL+L to clear the screen.
Theechocommand is used to print the parameter passed to it. The syntax to use theechocommand is:
echo
At times, you may have to use a very big set of commands multiple times. So, to save time from typing the big commands again and again, use the alias command. It is used to replace the big commands with a smaller character set. The syntax to create an alias is:
alias =""
To remove an alias, use theunaliascommand as shown below:
unalias <alias_name>
If you are stuck in a system without a GUI and need to do some simple calculations, you can use thebccommand. It will open a terminal-based calculator. To open thebccalculator, use the following syntax:
bc
Theexitcommand is used to exit out of the current terminal session. Use the following syntax to use the exit command:
exit
These are probably the most essential Linux commands you will ever need. In Linux, you can install almost all packages and software using the distro’s respective package managers. For Debian-based systems, you haveaptpackage manager, for Fedora and RedHat-based systems, you havednfpackage manager, and for Arch-based systems, you can use thepacmanpackage manager. Apart from these distro-specific package managers, you can also use snap or flatpak which can work on anyLinux distro. To install any packages using theaptpackage manager, use the syntax:
sudo apt install <package_name>
For installing packages using thednf, use the following syntax:
sudo dnf install <package_name>
To install any package using thepacmanpackage manager, use the given syntax:
sudo pacman -S <package_name>
To install any package using thesnappackage manager, use the given syntax:
sudo snap install <package_name>
For flatpak, use the given syntax:
sudo flatpak install <package_name>
If you ever need to know what is your IP address, MAC address, etc. you can use either theipcommand or theifconfigcommand. Theifconfighas more features thanipcommand but has to be installed separately with the command:
sudo apt install wireless-tools
To see the IP address of your network interface, using theIPcommand:
ip addr
And the syntax for using theifconfigcommand is as follows:
ifconfig
Use thepingcommand to test the network strength, as shown below:
ping <ip_address>
The shell operators are a fantastic way to combine Linux commands and run as a single one. There are a few important ones that you’ll be using such as:
The ‘&’ operator
The ‘&’ operator allows you to run any command in the background so that you can use the terminal for other tasks. For example, you need to copy a huge file which will take a lot of time to finish, thereby, blocking your terminal for any other use. In such a situation, you can use the regularcpcommand as shown above but add an ampersand symbol (&) at the end to let the command run in the background.
The ‘&&’ operator
Even though the ‘&&’ symbol looks similar to the ‘&’ but it works completely differently. The ‘&&’ allows us to run two or more commands at the same time. The syntax to use the ‘&&’ operator is:
command_1 && command_2
Here, we have combined two commands to run in a single line, but thecommand_2will get executed once thecommand_1finishes executing.
The ‘>’ operator
The ‘>’ operator works as an output redirector and redirects the output of one command to another command and is known as the “overwrite operator”. This operator will help you to overwrite the contents of a file without even opening a text editor. For example:
echo “Test line” > test.txt
This command will overwrite the contents of the test.txt file with the line “Test line”.
The ‘»’ operator
This operator is known as the “append operator” and works similarly to the “overwrite operator,” except this does not overwrite a file with new contents but helps you to add new content at the end of the file. For example:
echo “Hello World” » test.txt
This command will add the output of the first command at the end of the file “test.txt” without overwriting the contents of the file.
We have covered several useful Linux commands which will help you to use the command line easily. If you ever feel stuck or can’t remember the flags or the command syntax, be sure to check the official man pages. Hope this article has helped you to learn some new Linux commands. In case of any problem, do let us know in the comments below.
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