This page provides a comprehensive overview of the most commonly used commands in Linux. It covers a wide range of commands that are essential for navigating the Linux operating system, managing files and directories, working with users and permissions, networking, process management, system information, and more.
The article is structured into sections, making it easy to locate commands based on their respective categories. Each command is presented with a brief description of its functionality and usage. The commands are accompanied by examples and explanations, enabling readers to understand how they can be applied in practical scenarios.
File and directory operations involve various commands that allow you to interact with files and directories in Linux. Here is a brief description of some common file and directory operations:
Command | Description |
---|---|
ls |
Lists all files and directories in the present working directory |
ls -R |
Lists files in sub-directories as well |
ls -a |
Lists hidden files as well |
ls -al |
Lists files and directories with detailed information like permissions, size, owner, etc. |
cd or cd ~ |
Navigate to HOME directory |
cd .. |
Move one level up |
cd |
To change to a particular directory |
cd / |
Move to the root directory |
cat > filename |
Creates a new file and then allow you to add on the file. Ctrl D to get out of it. |
cat filename |
Displays the file content |
cat file1 file2 > file3 |
Joins two files (file1, file2) and stores the output in a new file (file3) |
mv file "new file path" |
Moves the files to the new location |
mv filename new_file_name |
Renames the file to a new filename |
rm filename |
Deletes a file |
mkdir directoryname |
Creates a new directory in the present working directory or at the specified path |
rmdir |
Deletes an empty directory |
mv |
Renames or moves a file or directory |
User and permissions management commands help you manage users and control access to files and directories. Some common commands in this category include chown
for changing ownership of files and directories, chmod
for modifying file permissions, adduser
for adding new users, passwd
for changing user passwords, and userdel
for removing users.
Command | Description |
---|---|
chown user filename |
Changes the ownership of a file/directory |
chown user:group filename |
Changes the user and group for a file or directory |
sudo adduser username |
Adds a new user |
sudo passwd -l 'username' |
Changes the password of a user |
sudo userdel -r 'username' |
Removes a user and their home directory |
sudo usermod -a -G GROUPNAME USERNAME |
Adds a user to a group |
sudo deluser USER GROUPNAME |
Removes a user from a group |
chmod |
Changes the permissions of a file or directory |
chmod +x filename |
Grants execute permission to a file |
chmod u+rwx filename |
Grants read, write, and execute permissions to the owner |
Text editing commands are used to create, modify, and view text files in Linux. The most commonly used text editor in Linux is vi
or vim
. Commands like i
, a
, and o
are used to insert text in vi, while dd
and dw
are used to delete text. Other commands like y
, p
, and :wq
are used for copying, pasting, and saving changes, respectively.
Command | Description |
---|---|
vi |
Opens the vi text editor |
i |
Inserts at the cursor position (goes into insert mode) |
a |
Writes after the cursor (goes into insert mode) |
A |
Writes at the end of the line (goes into insert mode) |
ESC |
Terminates insert mode |
u |
Undoes the last change |
U |
Undoes all changes to the entire line |
o |
Opens a new line (goes into insert mode) |
dd |
Deletes a line |
3dd |
Deletes 3 lines |
D |
Deletes contents of the line after the cursor |
C |
Deletes contents of a line after the cursor and inserts new text |
dw |
Deletes a word |
4dw |
Deletes 4 words |
cw |
Changes a word |
x |
Deletes a character at the cursor |
r |
Replaces a character |
R |
Overwrites characters from the cursor onward |
s |
Substitutes one character under the cursor and continues to insert |
S |
Substitutes the entire line and begins to insert at the beginning of the line |
~ |
Changes the case of an individual character |
Networking commands in Linux help you manage network connections and troubleshoot network-related issues. Commands like ping
are used to check network connectivity, ifconfig
displays network interface configuration, ssh
allows remote login to another machine, and scp
is used for secure file transfer between hosts.
Command | Description |
---|---|
ssh username@ip-address or hostname |
Logs into a remote Linux machine using SSH |
ping hostname |
Pings and analyzes network and host connections |
scp file username@hostname:destination |
Copies a file securely to a remote server |
ssh-keygen |
Generates SSH key pairs |
ifconfig |
Displays network interface configuration |
netstat |
Displays network connections and statistics |
Process management commands are used to monitor and control running processes in Linux. ps
displays information about running processes, kill
terminates processes, top
provides real-time monitoring of processes, and bg
and fg
are used to manage processes in the background and foreground, respectively.
Command | Description |
---|---|
ps |
Gives the status of processes running for a user |
ps PID |
Gives the status of a particular process |
pidof |
Gives the Process ID (PID) of a process |
kill PID |
Terminates a process |
top |
Details on all active processes |
bg |
Sends a process to the background |
fg |
Runs a stopped process in the foreground |
System information commands provide information about the system's hardware and software. Commands like date
display the current date and time, uptime
shows system uptime, who
lists the currently logged-in users, and df
provides information about disk space usage.
Command | Description |
---|---|
date |
Displays the current date and time |
cal |
Displays a calendar |
uptime |
Displays system uptime |
who |
Lists users currently logged in |
df |
Gives free hard disk space on your system |
free |
Gives free RAM on your system |
There are various other useful commands in Linux that perform different tasks. Some examples include history
for displaying command history, clear
for clearing the terminal screen, and exit
for exiting the current shell or terminal session. These commands help enhance productivity and perform routine tasks efficiently.
Command | Description |
---|---|
history |
Displays a list of previously executed commands |
clear |
Clears the terminal screen |
exit |
Exits the current shell or terminal session |
Computer Science
Sulav Jung Hamal - 2024/08/20