Most Used Linux Commands

Command Description Example Usage
ls List the files and directories in the current directory
ls -l List files in long format
ls -a List all files, including hidden files
ls -lh List files in long format with human-readable file sizes
ls -R Recursively list all subdirectories
cd Change the current directory to the user's home directory
cd /path/to/directory Change the current directory to a specific directory
cd .. Move up one level in the directory structure
cd - Change the current directory to the previous directory
mkdir Create a new directory
mkdir directory Create a directory with the given name in the current directory
mkdir -p /path/to/directory Create a directory along with its parent directories
mkdir -m 777 directory Create a directory with the given permissions
grep Searches for a specific pattern in a file or input
grep "pattern" file.txt Search for the pattern in a specific file
grep -r "pattern" /path/to/directory Search for the pattern in all files in the given directory and its subdirectories
cat file.txt | grep "pattern" Search for the pattern in the output of a command
touch Create a new empty file or update modification and access timestamps of an existing file
touch file.txt Create a new empty file with the given name
touch -a file.txt Update only the access timestamp of the file
touch -m file.txt Update only the modification timestamp of the file
cp Copy files and directories
cp file.txt /path/to/destination Copy a file to a specific directory
cp -r directory /path/to/destination Copy a directory to a specific directory
cp -a source destination Preserve file attributes and permissions while copying
cp file1.txt file2.txt /path/to/destination Copy multiple files to a specific directory
rm Delete files and directories
rm file.txt Delete a file
rm -r directory Delete a directory and its contents
rm -f file.txt Delete a file without prompting for confirmation
rm -i file.txt Delete a file and prompt for confirmation before deleting
mv Move or rename files and directories
mv file.txt /path/to/destination Move a file to a specific directory
mv directory /path/to/destination Move a directory to a specific directory
mv file.txt newfile.txt Rename a file
mv -i file.txt /path/to/destination Move a file and prompt for confirmation before overwriting
pwd Show the current working directory
pwd Show the current working directory
pwd -P Show the physical current working directory (all symbolic links resolved)
pwd -L Show the logical current working directory (the path without symbolic links)
cat Concatenate and display the contents of files
cat file1 Display the contents of file1
cat file1 file2 file3 Display the contents of file1, file2 and file3
cat file1 > newfile Redirect the contents of file1 to create a new file named newfile
cat file1 >> existingfile Append the contents of file1 to an existing file named existingfile
less View the contents of a file one screen at a time
less file1 View the contents of file1 one screen at a time
less +10 file1 Start viewing the contents of file1 from line number 10
ls -l | less Display the output of ls command one screen at a time
more View the contents of a file one screen at a time
more file1 View the contents of file1 one screen at a time
more +10 file1 Start viewing the contents of file1 from line number 10
ls -l | more Display the output of ls command one screen at a time
whoami Show the username of the current user
whoami Show the username of the current user
sudo Execute a command as the superuser (root user)
sudo command Execute the given command as root user
sudo -i Log in as the superuser (root user) and execute the shell
sudo su Switch to the superuser (root user) account
find Search for files and directories in a directory hierarchy
find directory/ -name "filename" Find all files with the given name in the specified directory
find directory/ -type f -mtime +7 -delete Delete all files in the specified directory that are older than 7 days
find directory/ -type d -empty -delete Delete all empty directories in the specified directory
du Estimate file space usage
du -sh * Display the total size of all files and directories in the current directory
du -sh directory/ Display the total size of the specified directory
du -sh directory/* Display the total size of all files and directories in the specified directory
head Output the first part of files
head file.txt Display the first 10 lines of the specified file
head -n 20 file.txt Display the first 20 lines of the specified file
head -c 100 file.txt Display the first 100 bytes of the specified file
tail Displays the last part of a file
tail filename.txt Display the last 10 lines of filename.txt
tail -n 20 filename.txt Display the last 20 lines of filename.txt
tail -f filename.txt Displays the last 10 lines of filename.txt and waits for new data to be appended to the file
tar Compresses and archives files
tar -cvf archive.tar file1.txt file2.txt Create a tar archive of file1.txt and file2.txt
tar -xvf archive.tar Extracts the files from archive.tar
tar -czvf archive.tar.gz folder Create a gzipped tar archive of folder
chmod Changes the permissions of a file or directory
chmod 777 file.txt Gives read, write and execute permissions to the owner, group and others on file.txt
chmod u+x file.txt Adds executable permission for the owner of file.txt
chmod 644 file.txt Gives read and write permissions to the owner and read permissions to the group and others on file.txt
chown Change the ownership of files and directories
chown user:group file Change the ownership of a file to a specific user and group
chown user:group directory/ Change the ownership of a directory and its contents to a specific user and group
chown -R user:group directory/ Recursively change the ownership of a directory and its contents to a specific user and group
kill Terminate running processes
kill process_id Terminate a process with the given process ID
killall process_name Terminate all processes with the given name
kill -9 process_id Forcefully terminate a process with the given process ID
top Display and manage running processes
top Display a list of running processes, sorted by CPU usage
top -u username Display a list of running processes for a specific user
top -p process_id Display information about a specific process with the given process ID
htop Interactive process viewer
htop Display a list of running processes, sorted by CPU usage
htop -u username Display a list of running processes for a specific user
htop -p process_id Display information about a specific process with the given process ID
ping Send ICMP ECHO_REQUEST packets to network hosts
ping hostname Send ICMP ECHO_REQUEST packets to the specified hostname or IP address
ping -c count hostname Send a specified number of packets to the specified hostname or IP address
ping -i interval hostname Send packets at a specified interval (in seconds) to the specified hostname or IP address
wget Download files from the web
wget URL Download the file at the specified URL
wget -O filename URL Download the file at the specified URL and save it with the specified filename
wget -r URL Recursively download all files linked from the specified URL
history Show a list of previously executed commands
history Show the full history of executed commands
history n Show the last n executed commands
man Display the manual page for a command
man command Display the manual page for the specified command
man -k keyword Search for manual pages containing the specified keyword
zip Compress files into a zip archive
zip archive.zip file1 file2 dir1 Create a new zip archive containing file1, file2, and dir1
zip -r archive.zip dir1 Create a new zip archive containing the contents of dir1 recursively
zip -u archive.zip file1 Add file1 to an existing zip archive or update it if it already exists
unzip Extract files from a ZIP archive
unzip archive.zip Extract all files from the archive
unzip archive.zip file.txt Extract a specific file from the archive
unzip -l archive.zip List the contents of the archive
echo Print a string or value to the terminal
echo "Hello, world!" Print the string "Hello, world!" to the terminal
echo $PATH Print the value of the PATH environment variable to the terminal
echo -e "Line 1\nLine 2" Print a string with a newline character
hostname Display the system's hostname
hostname Display the system's hostname
hostname -I Display the system's IP address
hostnamectl set-hostname newhostname Set the system's hostname to "newhostname"
useradd Create a new user account
useradd username Create a new user account with the given username
useradd -m username Create a new user account with the given username and create a home directory for the user
useradd -g groupname username Create a new user account with the given username and add the user to the specified group
userdel Delete a user account
userdel username Delete the user account with the given username
userdel -r username Delete the user account with the given username and remove the user's home directory and mail spool
su Switch to another user account
su username Switch to the specified user account
su - Switch to the root user account
clear Clear the terminal screen
clear Clear the terminal screen
export Set environment variables
export VAR=value Set the value of the environment variable VAR to "value"
export VAR Display the value of the environment variable VAR
apt Advanced Package Tool
apt update Update the package list from the repositories
apt upgrade Upgrade all installed packages to the latest versions
apt install package_name Install a package from the repositories
apt remove package_name Remove a package from the system
apt search search_term Search for a package in the repositories
pacman Package manager for Arch Linux
pacman -Sy Update the package database
pacman -S package_name Install a package
pacman -Syu Upgrade all installed packages
pacman -Q List all installed packages
pacman -R package_name Remove a package
yum Yellowdog Updater Modified
yum install package_name Install a package
yum remove package_name Remove a package
yum update Update all installed packages
yum upgrade package_name Upgrade a package to the latest version
yay Arch Linux package manager (AUR helper)
yay -S package_name Install a package from the AUR and its dependencies
yay -Syu Update all packages in the system including the AUR packages
yay -Ss package_name Search for a package in the AUR and repositories
uname Print system information
uname Display the name of the current operating system
uname -a Display all system information, including the kernel version
uname -r Display the kernel release
file Determine file type
file filename Display the type of the specified file
file * Display the type of all files in the current directory
file -i filename Display the MIME type of the specified file
date Display the current date and time
date '+%A, %B %-d %Y %T %Z' Display the date and time in a specific format
date '+%s' Display the number of seconds since the Unix Epoch
cal Display a calendar for the current month
cal 2023 Display a calendar for the year 2023
cal 03 2023 Display a calendar for March 2023
uptime Display how long the system has been running and the average system load over the past 1, 5, and 15 minutes
uptime -p Display the uptime in a more human-readable format
curl Transfer data from or to a server
curl URL Download the content of the URL
curl -O URL Download the file from the URL and save it with the original name
curl -o filename URL Download the file from the URL and save it with the specified name
wc Print newline, word, and byte counts for each file
wc filename Print newline, word, and byte counts for the file
wc -l filename Print only the newline count for the file
wc -w filename Print only the word count for the file
ip Show/manipulate routing, network devices, interfaces and tunnels
ip address Show IP addresses assigned to network interfaces
ip route Show the routing table
ip link Show information about network interfaces
dd Convert and copy a file, create disk images
dd if=/dev/zero of=/path/to/file bs=1M count=10 Create a 10MB file filled with zeros
dd if=/dev/cdrom of=/path/to/image.iso Create an ISO image of a CD/DVD
dd if=/dev/sda of=/path/to/image.img bs=1M Create an image of a disk
ssh Secure Shell - Connect to a remote server securely
ssh username@remote_host Connect to a remote host as a user named 'username'
ssh -p 2222 username@remote_host Connect to a remote host on port 2222
ssh -X username@remote_host Enable X11 forwarding for GUI applications
uniq Remove duplicate lines from a file
uniq file.txt Print the unique lines in a file
uniq -c file.txt Count the number of occurrences of each line in a file
sort file.txt | uniq Remove duplicate lines from a sorted file
sort Sort lines of text files
sort file.txt Sort contents of file.txt in ascending order
sort -r file.txt Sort contents of file.txt in descending order
sort -n file.txt Sort contents of file.txt numerically
cryptsetup Utility for setting up encrypted filesystems
cryptsetup luksFormat /dev/sdb1 Create an encrypted partition on /dev/sdb1 using LUKS
cryptsetup luksOpen /dev/sdb1 myencrypteddisk Unlock the encrypted partition /dev/sdb1 and mount it as myencrypteddisk
cryptsetup luksClose myencrypteddisk Close the encrypted partition named myencrypteddisk
mount Mount a filesystem
mount /dev/sdb1 /mnt/usb Mount the filesystem on /dev/sdb1 to /mnt/usb
mount -o remount,rw /mnt/usb Remount the /mnt/usb filesystem with read-write permissions
mount -t nfs 192.168.1.100:/mnt/nfs /mnt/local Mount the NFS share from 192.168.1.100:/mnt/nfs to /mnt/local
umount Unmount a filesystem
umount /mnt/usb Unmount the filesystem mounted on /mnt/usb
umount -l /mnt/usb Force unmount the filesystem mounted on /mnt/usb (if it is busy)
umount -a Unmount all currently mounted filesystems
fdisk Partition table manipulator for Linux
fdisk -l List all available disks and partitions
fdisk /dev/sdX Interactively create a new partition table on /dev/sdX
fdisk -l /dev/sdX List the partitions on /dev/sdX
cfdisk Interactive disk partitioning tool
cfdisk /dev/sdX Interactively partition /dev/sdX
nano A friendly, easy-to-use text editor
nano filename Edit the file "filename" with nano
Ctrl+G Show the help screen
Ctrl+X Exit nano and save changes
vi A classic, powerful text editor
vi filename Edit the file "filename" with vi
i Enter insert mode to begin editing the file
Esc Exit insert mode and return to command mode
:w Save changes to the file
:q Quit vi
:q! Force quit vi and discard changes
nc Network utility for reading from and writing to network connections
nc host port Connect to the specified host and port
nc -l port Listen on the specified port for incoming connections
nc -u host port Use UDP instead of the default TCP protocol
netstat Print network connections, routing tables, interface statistics, etc.
netstat -t Show TCP connections
netstat -u Show UDP connections
netstat -r Show routing table
tcpdump Packet analyzer for network traffic
tcpdump -i interface Listen on the specified network interface
tcpdump host ip_address Capture packets for the specified host IP address
tcpdump -n Do not resolve hostnames
nmap Network exploration tool and security scanner
nmap host Scan a single host
nmap -sS host Perform a stealth SYN scan
nmap -O host Enable OS detection on the target host
awk Pattern scanning and processing language
awk '/pattern/ {print $1}' file Print the first field of each line that matches a pattern in a file
awk '{print $1, $3}' file Print the first and third fields of each line in a file
awk -F: '{print $1}' /etc/passwd Print the first field of each line in the /etc/passwd file using colon as the field separator
cut Extracts sections from each line of a file
cut -f1,3 -d: /etc/passwd Extract the first and third fields of each line in the /etc/passwd file using colon as the field separator
cut -c1-5 file Extract the first five characters of each line in a file
cut -f2- file Extract all fields from the second field to the end of each line in a file
passwd Change user password
passwd Change the password for the current user
passwd username Change the password for the specified user
passwd -l username Lock the specified user's password, disabling login
passwd -u username Unlock the specified user's password, enabling login
tee Read from standard input and write to standard output and files
command | tee file.txt Write the output of 'command' to both the console and the file 'file.txt'
command1 | tee >(command2) Write the output of 'command1' to both the console and the input of 'command2'
command | tee -a file.txt Append the output of 'command' to the end of the file 'file.txt'
git Version control system for software development
git init Initialize a new Git repository in the current directory
git clone [repository_url] Clone a Git repository from a remote URL
git add [file] Add a file to the staging area for the next commit
git commit -m "[commit_message]" Create a new commit with the changes in the staging area and a commit message
git push [remote] [branch] Push changes to a remote repository on a specific branch
git pull [remote] [branch] Pull changes from a remote repository on a specific branch
git merge [branch] Merge a branch into the current branch
ftp File Transfer Protocol
ftp hostname Connect to the FTP server with the specified hostname
ftp -u username hostname Connect to the FTP server with the specified username and hostname
ftp ftp://username@hostname Connect to the FTP server with the specified username and hostname using FTP URL syntax
get remote-file [local-file] Download the remote file from the FTP server to the local system. If local-file is not specified, the file is downloaded to the current working directory with the same name.
put local-file [remote-file] Upload the local file to the FTP server. If remote-file is not specified, the file is uploaded to the current directory on the FTP server with the same name.
scp Secure Copy
scp [options] source destination Copy files securely between hosts on a network
scp file.txt user@192.168.0.10:/home/user/ Copy the file.txt from the local system to the remote system at IP address 192.168.0.10 and save it to the /home/user/ directory.
scp user@192.168.0.10:/home/user/file.txt . Copy the file.txt from the remote system at IP address 192.168.0.10 to the current directory on the local system.
scp -r /path/to/local/dir user@remote:/path/to/remote/dir Recursively copy the local directory to the remote system.
dig DNS lookup utility
dig example.com Perform a DNS lookup for the domain name example.com
dig -x IP_address Perform a reverse DNS lookup for the given IP address
dig @DNS_server example.com Perform a DNS lookup using the specified DNS server
telnet Remote login client
telnet example.com Connect to the remote host example.com using the telnet protocol
telnet IP_address Connect to the remote host with the given IP address using the telnet protocol
telnet example.com port_number Connect to the specified port on the remote host example.com using the telnet protocol