Linux Commands Cheat Sheet [With PDF]

Welcome to the Linux Commands Cheat Sheet! This handy guide is perfect for anyone who's looking to navigate through Linux's commands more easily.

System Based Commands

`uname`	Displays system information: kernel version, machine type, and more.
`uname -r`	Displays the running Linux kernel's release version.
`uptime`	Shows current time, system uptime, users, and load averages.
`hostname`	Shows the system hostname.
`hostname -i`	Displays the IP address of the current host.
`last reboot`	Shows last reboot times and durations in logs.
`date`	Displays the current date and time information.
`timedatectl`	Displays detailed system clock and time zone information.
`cal`	Displays a simple calendar of the current month.
`w`	Shows who is logged on and their activity.
`whoami`	Displays the username of the current user.
`finger username`	Displays information about a user named 'username'.

`dmesg`	Displays messages from the kernel's ring buffer.
`cat /proc/cpuinfo`	Displays detailed information about the CPU.
`cat /proc/meminfo`	Displays detailed system memory usage information.
`lscpu`	Lists information about the CPU.
`lshw`	Lists detailed hardware configuration of the system.
`lsblk`	Lists information about all available block devices.
`free -m`	Shows system memory usage in megabytes.
`lspci -tv`	Displays PCI devices in tree format, verbosely.
`lsusb -tv`	Shows USB devices as a tree, verbosely.
`dmidecode`	Displays hardware information from system BIOS
`hdparm -i /dev/sda`	Displays information of disk /dev/sda.
`badblocks -s /dev/sda`	Checks /dev/sda for bad blocks, showing progress.

`id`	Displays the user's UID, GID, and groups.
`last`	Shows list of last logged-in users.
`who`	Displays who is currently logged in.
`groupadd admin`	Creates a new user group named admin.
`adduser Sam`	Creates a new user account named Sam.
`userdel Sam`	Deletes the user account named Sam.
`usermod`	Modifies properties of an existing user account.

`ls -al`	Lists all files, detailed information, in long format.
`pwd`	Displays the present working directory's path.
`mkdir dir1`	Creates a new directory named dir1.
`rm file1`	Deletes the file named file1.
`rm -f file2`	Forcefully deletes the file named file2.
`rm -r dir1`	Recursively removes directory dir1 and its contents.
`rm -rf dir1`	Forcefully deletes directory dir1 and its contents.
`cp file1 file2`	Copies file1, creating or overwriting file2.
`cp -r dir1 dir2`	Copies dir1 to dir2, including subdirectories.
`mv file1 file2`	Renames or moves file1 to file2.
`ln -s /path/to/file_name link_name`	Creates symbolic link named link_name to file_name.
`touch file1`	Creates an empty file named file1.
`cat > file1`	Creates/overwrites file1, awaiting standard input.
`more file1`	Displays file1 content, paginating through output.
`head file1`	Displays the first ten lines of file1.
`tail file1`	Displays the last ten lines of file1.
`gpg -c file1`	Encrypts file1 with symmetric cipher using passphrase.
`gpg file2.gpg`	Decrypts file2.gpg, prompting for the passphrase.
`wc`	Counts words, lines, and characters in files.
`xargs`	Executes commands with piped or file-provided arguments.

`ps`	Displays a snapshot of current processes.
`ps aux \| grep telnet`	Displays running telnet processes with details.
`pmap`	Shows memory map of a process.
`top`	Displays dynamic real-time view of running tasks.
`kill 1234`	Terminates the process with PID 1234.
`killall proc`	Kills all processes named 'proc'.
`pkill process-name`	Terminates processes with the name.
`bg`	Resumes suspended jobs in the background
`fg`	Brings a suspended job to foreground
`fg n`	Brings job number 'n' to foreground.
`lsof`	Lists all open files and processes.
`renice 19 PID`	Changes priority of process with given PID.
`pgrep firefox`	Displays Process ID(s) for firefox processes.
`pstree`	Displays a tree of running processes.

`chmod 644 /data/test.c`	Sets the permissions of the file `/data/test.c` to be read/write for the owner, and read-only for the group and others.
`chmod 755 /dir1`	Assigns read, write, and execute permissions to the owner, and read and execute permissions to the group and others for the directory `/dir1`.
`chown bob:devops filename`	Changes file 'filename' ownership to 'bob' and 'devops'.
`chown ownername:groupname directory`	Change owner and group of the directory.

`ip addr show`	Displays all network interfaces and their information.
`ip address add 192.168.0.1/24 dev eth0`	Assigns IP address 192.168.0.1 to interface eth0.
`ifconfig`	Shows network interfaces and their configuration.
`ping host`	Sends ICMP packets, measures round-trip time to "host".
`whois domain`	Retrieves and displays domain's registration information.
`dig domain`	Queries DNS, provides domain's DNS information.
`dig -x host`	Resolves IP address to hostname, shows DNS information.
`host google.com`	Performs an IP lookup for the domain name
`wget file_path`	Downloads file from specified path.
`netstat`	Displays various network-related information and statistics.
`ss`	Display information about network sockets.

`tar -cf backup.tar /home/ubuntu`	Creates a tar archive of /home/ubuntu directory.
`tar -xf backup.tar`	Extracts files from "backup.tar" archive.
`tar -zcvf backup.tar.gz /home/ubuntu`	Creates compressed "backup.tar.gz" archive of "/home/ubuntu"
`gzip file1`	Compresses "file1" into "file1.gz", original is removed.

`rpm -i pkg_name.rpm`	Installs the package "pkg_name.rpm" using RPM Package Manager.
`rpm -e pkg_name`	Uninstalls the specified RPM package.
`dnf install pkg_name`	Installs the specified package using DNF.
`pacman -S pkg_name`	Installs the specified package using Pacman.

`./configure`	Checks system compatibility and generates makefile for software installation.
`make`	Compiles code by following instructions in the Makefile.
`make install`	Installs compiled code into specified system locations.

`grep pattern file`	Search for a given pattern within the file.
`grep -r pattern dir1`	Recursively searches for the specified "pattern" within the "dir1" directory and its subdirectories
`locate file`	Finds files named "file" using prebuilt database.
`find /home -name index`	Searches "/home" directory for files named "index" recursively.
`find /home -size +10000k`	Finds files over 10000k size in /home directory.

`ssh user@hostname`	Initiates SSH connection to specified hostname.
`ssh -p port_number user@hostname`	Initiates SSH connection using specific port.
`ssh hostname`	Securely connect to the system via SSH default port 22
`telnet host`	Connect to the host via telnet default port 23.

`scp file.txt remoteuser@remote_host:/remote/directory`	Copies file.txt to remote host's specified directory.
`rsync -a /home/ubuntu /backup/`	Synchronizes content from source directory to destination directory,preserving attributes.
`rsync -a /var/www/web/ user@remote_host:/backup/web_backup/`	Synchronizes local directory to remote, preserving attributes.

`df -h`	Displays human-readable disk space usage for all mounted filesystems.
`df -i`	Displays inode usage information for all mounted filesystems.
`fdisk -l`	Lists all partitions and their information on all drives.
`du -sh /dir1`	Displays summary of total disk usage size of /dir1, human-readable.
`findmnt`	Displays a list of all mounted filesystems and their properties.
`mount device-path mount-point`	Mounts the device at the specified filesystem mount point.