The terminal in Linux is an interface in which you can type and execute text-based commands. It allows for efficient management of the operating system and software, providing a direct way to interact with the system's kernel and services. Unlike graphical user interfaces (GUIs), the terminal provides a lightweight, more controlled, and scriptable way of interacting with the computer.
Graphical Method: On most Linux desktop environments, you can open the terminal from the applications menu. Look for "Terminal".
Keyboard Shortcut: Many distributions allow you to open a terminal window by pressing Ctrl + Alt + T.
Prints the path of the current working directory.
Changes the working directory, abbreviation for 'change directory'.
cd <folder>: Go into a folder.cd: Go to home directory.cd ..: Go 1 directory up.cd ../..: Go 2 directories up.cd ../../etc: Go 2 directories up and go to theetcfolder.cd ~: Go to your home directory.
Creates a folder inside the working directory.
mkdir dir1: Create a folder nameddir1in the current directory.mkdir dir1 dir2 dir3: Create multiple folders in the current directory.mkdir ~/Desktop/dir1: Create a folder nameddir1on the existing desktop directory.mkdir -p dir1/dir2/dir3: Create parented directories, creating intermediate folders if they don't exist.
Lists files in the working directory.
ls: List files and folders in the current directory.ls -a: List all files, including hidden ones.ls -l: Detailed list view with file information such as permissions and size.ls -lh: List files in a human-readable format.ls dir1: List the contents of thedir1directory.
Creates a new empty file.
touch output.txt: Creates an empty file namedoutput.txt.
Writes output to files:
>: Writes the output of a command to a file, overwriting the file if it exists.pwd > output.txt: Writes the path of the working directory tooutput.txt.
>>: Appends the output of a command to a file.pwd >> output.txt: Appends the path of the working directory tooutput.txt.
Stands for Concatenate. Creates, views, and concatenates files:
cat output.txt: Displays the contents ofoutput.txt.cat file1.txt file2.txt > merged.txt: Concatenates two files intomerged.txt.
Moves or renames files and directories:
mv output.txt dir1/: Movesoutput.txtto thedir1directory.mv dir1/* .: Moves everything fromdir1to the current directory.mv oldname.txt newname.txt: Renames a file.
Copies files and directories:
cp output.txt output2.txt: Copiesoutput.txttooutput2.txt.cp -r dir1 dir2: Recursively copies thedir1directory todir2.
markdown Copy code
Prints the path of the current working directory: pwd
Changes the working directory:
cd: Go to the home directory.cd ..: Go one directory up.cd ../..: Go two directories up.cd ../../etc: Go two directories up and into theetcfolder.cd ~: Go to the user's home directory.cd -: Switch back to the previous working directory.
Creates a folder inside the working directory:
mkdir dir1: Create a folder nameddir1in the current directory.mkdir dir1 dir2 dir3: Create multiple folders in the current directory.mkdir ~/Desktop/dir1: Create a folder nameddir1on the desktop.mkdir -p dir1/dir2/dir3: Create parented directories, creating intermediate folders if they don't exist.
Lists files in the working directory:
ls: List files and folders in the current directory.ls -a: List all files, including hidden ones.ls -A: List all files, including hidden ones but without the current and parent directories (.and..)ls -l: Detailed list view with file information such as permissions and size.ls -lh: List files in a human-readable format.ls dir1: List the contents of thedir1directory.
Creates a new empty file:
touch output.txt: Creates an empty file namedoutput.txt.
Writes output to files:
>: Writes the output of a command to a file, overwriting the file if it exists.- Example:
pwd > output.txt: Writes the path of the working directory tooutput.txt.
- Example:
>>: Appends the output of a command to a file.- Example:
pwd >> output.txt: Appends the path of the working directory tooutput.txt.
- Example:
Creates, views, and concatenates files:
cat output.txt: Displays the contents ofoutput.txt.cat file1.txt file2.txt > merged.txt: Concatenates two files intomerged.txt.
Moves or renames files and directories:
mv output.txt dir1/: Movesoutput.txtto thedir1directory.mv dir1/* .: Moves everything fromdir1to the current directory.mv oldname.txt newname.txt: Renames a file.
Copies files and directories:
cp output.txt output2.txt: Copiesoutput.txttooutput2.txt.cp -r dir1 dir2: Recursively copies thedir1directory todir2.
Removes files and directories:
rm output.txt: Removesoutput.txt.rm -rf dir1: Recursively removesdir1and its contents.
Determines the file type of a given file:
file image.jpg: Displays the file type ofimage.jpg.
Displays detailed information about a file or file system:
stat filename.txt: Shows file details including inode, size, and permissions.
Creates links between files.
ln -s source.txt link.txt: Creates a symbolic link namedlink.txtpointing tosource.txt.ln source.txt link.txt: Creates a hard link namedlink.txttosource.txt.
Counts lines, words, and characters in a file:
wc filename.txt: Displays line, word, and character count for the file.wc -l filename.txt: Displays the line count only.ls -A | wc -l: Displays the file count in the current directory.
Stream editor used for filtering and transforming text:
sed 's/old/new/' file.txt: Replaces the first occurrence of "old" with "new" in each line.sed -i 's/old/new/g' file.txt: Replaces all occurrences of "old" with "new" in the file.
Read more about sed here.
A powerful text processing tool:
awk '{print $1}' file.txt: Prints the first column of a file.awk '/pattern/ {print $0}' file.txt: Prints lines matching a pattern.
Read more about awk here.
Cuts specific sections from a file:
cut -d',' -f2 file.csv: Extracts the second column from a CSV file using,as a delimiter.
Displays large files one page at a time:
less largefile.txt: Openslargefile.txtfor paginated viewing.
Displays the first few lines of a file:
head -n 5 file.txt: Displays the first five lines of the file.
Displays the last few lines of a file:
tail -n 5 file.txt: Displays the last five lines of the file.tail -f logfile.txt: Continuously displays new lines added to a file in real time.
Compares the contents of two files line by line:
diff file1.txt file2.txt: Shows the differences line by line.
Sorts the lines in a file:
sort file.txt: Alphabetically sorts the file.sort -n file.txt: Sorts the file numerically.sort -r file.txt: Sorts the file in reverse order.sort -k 2 file.txt: Sorts by the second column.
Opens and edits files:
nano output.txt: Opensoutput.txtfor editing.
Read more about nano here.
Creates, extracts, or manipulates archive files:
tar -cvf archive.tar file1 file2: Creates an archive containingfile1andfile2.tar -xvf archive.tar: Extracts the contents ofarchive.tar.tar -czvf archive.tar.gz dir/: Creates a compressed archive of thedirdirectory.
Compresses and extracts files:
zip myzip.zip file1 file2: Compressesfile1andfile2intomyzip.zip.unzip myzip.zip: Extracts the contents ofmyzip.zip.
Displays files in a tree structure:
tree: Displays the directory structure starting from the current directory.tree -L 1: Displays the directory structure up to a depth of 1.
Searches for files and directories based on various criteria:
find . -name "*.py": Finds all.pyfiles in the current directory and subdirectories.find . -iname "*.py": Performs a case-insensitive search for.pyfiles.find /home/user/projects -type d -name build: Finds all directories namedbuildin/home/user/projects.find /home/user -mtime -7: Finds files modified in the last 7 days in/home/user.find /var/log -size +100M: Finds files larger than 100MB in/var/log.find /home/user/images -name "*.jpg" -exec mv {} /home/user/backup \;: Finds all.jpgfiles in/home/user/imagesand moves them to/home/user/backup.find /path/to/dir -name "*.tmp" -exec rm {} \;: Finds all.tmpfiles and deletes them.
Stands for “global regular expression print”, a powerful command used for searching text using patterns.
apt list | grep firefox: Filters the list of packages for "firefox."grep "word" filename.txt: Searches for a specific word in a file.grep -r "word" /path/to/directory: Recursively searches for a word in all files in a directory.grep -A 3 "pattern" filename.txt: Displays 3 lines after each pattern match.grep -i "pattern" filename.txt: Performs a case-insensitive search.grep -c "pattern" filename.txt: Counts the number of lines matching the pattern.
Outputs the username of the current user.
Displays a string or text passed as an argument:
echo "Hello World": Displays "Hello World" in the terminal.
Clears the terminal screen, making it blank.
Shows the manual page for commands, providing detailed information about command usage and options.
man mkdir: Shows the manual for themkdircommand.
Provides a more detailed guide for commands:
info mkdir: Shows detailed information aboutmkdir.
Displays previously entered commands in the terminal:
history: Shows the full command history.history | tail -n 20: Displays the last 20 commands.history -c: Clears the command history.
Changes file permissions:
chmod 755 file.txt: Grants read, write, and execute permissions for the owner and read/execute for others.
Executes a command with superuser privileges:
sudo apt install gimp: Installs the GIMP software.
Changes file ownership:
chown user file.txt: Assigns ownership offile.txttouser.
Changes the group ownership of a file:
chgrp group file.txt: Changes the group offile.txttogroup.
Sets default file permissions:
umask 022: Ensures new files are created with644permissions.
Switches to another user:
su user: Switches to the specified user.
Adds a new user:
adduser username: Creates a new user account namedusername.
Deletes a user:
deluser username: Removes the userusername.
Displays information about logged-in users:
who: Lists all users currently logged in.
Shows the login history of users:
last: Displays a list of user logins.
An interactive process viewer, offering a detailed overview of system processes and the ability to manage them directly.
htop: Opens a visual overview of system processes.
Terminates processes by PID or name:
kill 533494: Terminates the process with PID533494.killall firefox: Terminates all processes namedfirefox.
Displays all running processes:
ps aux: Lists all running processes.ps aux | grep firefox: Filters the list of processes for "firefox".
Executes a command that continues running in the background, immune to hangup signals.
nohup python script.py &: Runs script.py in the background, ensuring it continues even if the terminal closes.
Suspends a foreground process, moving it to the background in a stopped state. This allows the terminal to return to the prompt for other tasks while keeping the process's state intact.
Lists active or suspended jobs:
bg %1: Resumes job 1 in the background.fg %1: Brings job 1 to the foreground.
Displays disk usage for files and directories:
du -h /path/to/directory: Displays human-readable sizes.du -sh /path/to/directory: Displays the size of the directory.du -a -h /path/to/directory: Displays sizes of all files and directories.du -h --max-depth=1 /path/to/directory: Limits depth to show directory sizes.
Displays available disk space:
df -h: Shows disk space in a human-readable format.df -m: Shows disk space in mega bytes.
Shows memory usage:
free -h: Displays memory usage in a human-readable format.
Displays real-time process activity.
Interactive tool to analyze disk usage.
- Clean up the APT cache:
- List disk usage:
sudo du -sh /var/cache/apt - Clean:
sudo apt clean
- List disk usage:
- Remove packages you no longer need:
sudo apt autoremove - Cleanup journal logs:
- List disk usage:
journalctl --disk-usage - Remove logs from x-time:
sudo journalctl --vacuum-time=7d
- List disk usage:
- Clear thumbnail cache:
- List disk usage:
du -sh ~/.cache/thumbnails - Clear:
rm -rf ~/.cache/thumbnails
- List disk usage:
- Clear temporary files:
- List disk usage:
sudo du -sh /tmp - Clear:
sudo rm -rf /tmp/*
- List disk usage:
Shows system uptime and load averages:
uptime: Displays the current uptime.uptime -s: Shows the last boot time.
Displays system information:
uname -a: Displays all system information.
Displays or sets the system date and time:
date: Shows the current date and time.
Manages system time, date, and time zones:
timedatectl: Displays current time settings.
Safely shuts down or reboots the system.
shutdown now(Shuts down the system immediately.)shutdown -r +10(Reboots the system after a 10-minute delay.)
Reboots the system immediately.
Controls the systemd system and service manager.
systemctl status: Shows the status of all active systemd units.systemctl status NetworkManager: Shows the status of theNetworkManagerservice.systemctl enable <service>: Enables a service to start automatically at boot.systemctl disable <service>: Disables a service from starting at boot.systemctl restart <service>: Restarts a service.
Displays environment variables in the current shell session:
env: Lists all environment variables.
Sets environment variables in the current shell session:
export VAR=value: Sets the value ofVAR.
Unsets environment variables in the current shell session:
unset VAR: RemovesVAR.
Prints the value of a specific environment variable:
printenv PATH: Displays thePATHvariable.
Note
ifconfigis considered deprecated and replaced by theiptoolset.netstatis considered deprecated and replaced by thesstoolset.
List your IP addresses.
Ping to a device.
ping google.com(Pings google.com.)
Displays detailed information about network connections, listening ports, and the programs (processes) using those ports.
Transfers data using various protocols:
curl http://example.com: Fetches the content ofexample.com.curl -o output.html http://example.com: Saves the content tooutput.html.curl -O http://example.com/file.zip: Saves the file with its original name (file.zip).curl -T uploadfile.txt ftp://example.com/upload/: Upload a file to a ftp server.curl -u username:password https://example.com/api: Upload using authenication.curl -X GET https://api.example.com/resource: Send a HTTP GET.curl -X POST -d "key1=value1" https://api.example.com/resource: Send a HTTP POST.
Downloads files from the web:
wget http://example.com/file.zip: Downloadsfile.zip.wget -O my_files.zip http://example.com/file.zip: Downloadsfile.zip.-b: Runs the download in the background.--no-check-certificate: Skips SSL certificate validation.--spider: Checks if a file or URL exists without downloading it.--mirror: Mirrors a website, creating a local copy.
Copies files between systems:
scp file.txt user@remote:/path: Copiesfile.txtto a remote system.scp user@remote:/path/to/file.txt ./: Copiesfile.txtfrom the remote system to the current directory.scp -r localdir user@remote:/path/to/destination: Recursively copieslocaldirto the remote system.
Connects to a remote system securely:
ssh user@hostname: Logs intohostnameasuser.ssh -A user@hostname: Logs intohostnameasuserwith ssh agent forwarding.ssh user@hostname "ls -l /path/to/directory": Runs the command on the remote system and displays the output locally.ssh-copy-id user@hostname: Installs your public key on the remote system for passwordless login.