Linux Commands Cheat Sheet Every Linux Geek Need to Know

In the world of Linux, having comprehensive Linux commands cheat sheet by your side can be a game-changer.

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Whether you’re a beginner just starting out, or an experienced system administrator, these commands form the backbone of your Linux experience.

This article provides an extensive cheat sheet of Linux commands, compiled from three reputable sources.

It covers a wide range of commands, from system information and file handling to process management and network operations.

Each command is accompanied by a brief description to help you understand its function.

This Linux commands cheat sheet is designed to serve as a quick reference guide, helping you navigate the powerful Linux environment with ease and efficiency. So, let’s dive in and explore the power at your fingertips!

Top Linux Commands Cheat Sheet to Use

Remember to replace placeholders like file, directory, processname, pid, user, group, hostname, IP_ADDRESS, domain, keyword, package, sourcecode, pattern, name, prefix, port, server, and servicename with actual values when using these commands.

Command Description
uname -a Display Linux system information
uname -r Display kernel release information
cat /etc/os-release Show operating system information such as distribution name and version
uptime Show how long the system has been running + load
hostname Show system host name
hostname -I Display all local IP addresses of the host
last reboot Show system reboot history
date Show the current date and time
cal Show this month’s calendar
w Display who is online
whoami Who you are logged in as
dmesg Display messages in kernel ring buffer
cat /proc/cpuinfo Display CPU information
cat /proc/meminfo Display memory information
free -h Display free and used memory ( -h for human readable, -m for MB, -g for GB)
lspci -tv Display PCI devices
lsusb -tv Display USB devices
dmidecode Display DMI/SMBIOS (hardware info) from the BIOS
hdparm -i /dev/sda Show info about disk sda
hdparm -tT /dev/sda Perform a read speed test on disk sda
badblocks -s /dev/sda Test for unreadable blocks on disk sda
top Display and manage the top processes
htop Interactive process viewer (top alternative)
mpstat 1 Display processor related statistics
vmstat 1 Display virtual memory statistics
iostat 1 Display I/O statistics
tail -100 /var/log/messages Display the last 100 syslog messages (Use /var/log/syslog for Debian based systems)
tcpdump -i eth0 Capture and display all packets on interface eth0
tcpdump -i eth0 ‘port 80’ Monitor all traffic on port 80 ( HTTP )
lsof List all open files on the system
lsof -u user List files opened by user
free -h Display free and used memory ( -h for human readable, -m for MB, -g for GB)
watch df -h Execute “df -h”, showing periodic updates
id Display the user and group ids of your current user
last Display the last users who have logged onto the system
who Show who is logged into the system
w Show who is logged in and what they are doing
groupadd test Create a group named “test”
useradd -c “John Smith” -m john Create an account named john, with a comment of “John Smith” and create the user’s home directory
userdel john Delete the john account
usermod -aG sales john Add the john account to the sales group
ls -al List all files in a long listing (detailed) format
pwd Display the present working directory
mkdir directory Create a directory
rm file Remove (delete) file
rm -r directory Remove the directory and its contents recursively
rm -f file Force removal of file without prompting for confirmation
rm -rf directory Forcefully remove directory recursively
cp file1 file2 Copy file1 to file2
cp -r source_directory destination Copy source_directory recursively to destination. If destination exists, copy source_directory into destination, otherwise create destination with the contents of source_directory
mv file1 file2 Rename or move file1 to file2. If file2 is an existing directory, move file1 into directory file2
ln -s /path/to/file linkname Create symbolic link to linkname
touch file Create an empty file or update the access and modification times of file
cat file View the contents of file
less file Browse through a text file
head file Display the first 10 lines of file
tail file Display the last 10 lines of file
tail -f file Display the last 10 lines of file and “follow” the file as it grows
ps Display your currently running processes
ps -ef Display all the currently running processes on the system
ps -ef \| grep processname Display process information for processname
top Display and manage the top processes
htop Interactive process viewer (top alternative)
kill pid Kill process with process ID of pid
killall processname Kill all processes named processname
program & Start program in the background
bg Display stopped or background jobs
fg Brings the most recent background job to foreground
fg n Brings job n to the foreground
chmod 777 filename Change file permissions to 777 (use sparingly)
chmod 775 filename Change file permissions to 775
chmod 755 filename Change file permissions to 755
chmod 664 filename Change file permissions to 664
chmod 644 filename Change file permissions to 644
ip a Display all network interfaces and IP address
ip addr show dev eth0 Display eth0 address and details
ethtool eth0 Query or control network driver and hardware settings
ping host Send ICMP echo request to host
whois domain Display whois information for domain
dig domain Display DNS information for domain
dig -x IP_ADDRESS Reverse lookup of IP_ADDRESS
host domain Display DNS IP address for domain
hostname -i Display the network address of the host name
hostname -I Display all local IP addresses of the host
wget http://domain.com/file Download http://domain.com/file
netstat -nutlp Display listening tcp and udp ports and corresponding programs
tar cf archive.tar directory Create tar named archive.tar containing directory
tar xf archive.tar Extract the contents from archive.tar
tar czf archive.tar.gz directory Create a gzip compressed tar file name archive.tar.gz
tar xzf archive.tar.gz Extract a gzip compressed tar file
tar cjf archive.tar.bz2 directory Create a tar file with bzip2 compression
tar xjf archive.tar.bz2 Extract a bzip2 compressed tar file
yum search keyword Search for a package by keyword
yum install package Install package
yum info package Display description and summary information about package
rpm -i package.rpm Install package from local file named package.rpm
yum remove package Remove/uninstall package
tar zxvf sourcecode.tar.gz; cd sourcecode; ./configure; make; make install Install software from source code
grep pattern file Search for pattern in file
grep -r pattern directory Search recursively for pattern in directory
locate name Find files and directories by name
find /home/john -name ‘prefix*’ Find files in /home/john that start with “prefix”
find /home -size +100M Find files larger than 100MB in /home
ssh host Connect to host as your local username
ssh [email protected] Connect to host as user
ssh -p port [email protected] Connect to host using port
scp file.txt server:/tmp Secure copy file.txt to the /tmp folder on server
scp server:/var/www/*.html /tmp Copy *.html files from server to the local /tmp folder
scp -r server:/var/www /tmp Copy all files and directories recursively from server to the current system’s /tmp folder
rsync -a /home /backups/ Synchronize /home to /backups/home
rsync -avz /home server:/backups/ Synchronize files/directories between the local and remote system with compression enabled
df -h Show free and used space on mounted filesystems
df -i Show free and used inodes on mounted filesystems
fdisk -l Display disks partitions sizes and types
du -ah Display disk usage for all files and directories in human readable format
du -sh Display total disk usage off the current directory
cd .. To go up one level of the directory tree (Change into the parent directory)
cd Go to the $HOME directory
cd /etc Change to the /etc directory
passwd Change the current user’s password
sudo -i Switch to the root account with root’s environment (Login shell)
sudo -s Execute your current shell as root (Non-login shell)
sudo -l List sudo privileges for the current user
visudo Edit the sudoers configuration file
getenforce Display the current SELinux mode
sestatus Display SELinux details such as the current SELinux mode, the configured mode, and the loaded policy
setenforce 0 Change the current SELinux mode to Permissive (Does not survive a reboot)
setenforce 1 Change the current SELinux mode to Enforcing (Does not survive a reboot)
SELINUX=enforcing Set the SELinux mode to enforcing on boot by using this setting in the /etc/selinux/config file
SELINUX=permissive Set the SELinux mode to permissive on boot by using this setting in the /etc/selinux/config file
SELINUX=disabled Set the SELinux mode to disabled on boot by using this setting in the /etc/selinux/config file
dmesg Display messages in kernel ring buffer
journalctl Display logs stored in the systemd journal
journalctl -u servicename Display logs for a specific unit (service)

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