Linux Commands Cheat Sheet: 100+ Commands with Examples

In this cheat sheet tutorial I have consolidated a list of Linux commands with examples and man page link to give you an overview on Linux day to day usage. We know Linux is one of the preferred choice for most of the IT domains so having basic knowledge of Linux is mandatory for everyone. I have divided the Linux commands into different section so you can choose to only concentrate on the commands which suits your domain.

I will keep adding and updating this article from time to time to add more commands.

Environment Variables

Variables are local, which means they are specific to a process. Local means local to a process. For example, when you log in on a terminal or open a terminal emulator, you start a process that runs a shell and create this variable TEST with value as deepak

bash

TEST=deepak

Verify the content of this variable

bash


echo $TEST
deepak

Now you open another terminal of the same Linux server and try to access this variable,

bash

echo $TEST

The output would be empty, so our variable is only accessible in the terminal where we created.

Recommended Read:

Command	Example / Syntax	Comments	For more details
`printenv`	`printenv`	Displays environment variables or a specific variable value	man page
`env`	`env`	Runs a program with a modified environment	man page for env
`export`	`export TEST=deepak` `env \| grep TEST`	Sets environment variables for the shell session	man page
`set`	`TEST=deepak` `set \| grep TEST`	Displays all shell and environment variables	man page

File Management

The commands under this section are very basic commands and must be known to every system administrator. This is definitely not the complete list of Linux commands for file management but can give you a kickstart and can cover most of the basic to complex scenarios.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`ls`	`ls`, `ls -l`, `ls -la`, `ls -ltr`	List files (basic, long, hidden, sorted by time)	man page
`cat`	`cat FILENAME`	Print file content to terminal	man page
`less`	`less FILENAME`	View large files with navigation and scrolling	man page
`more`	`more FILENAME`	View file page by page (limited navigation)	man page
`head`	`head -n 5 FILE`	Show first lines of file (default 10)	man page
`tail`	`tail -n 5 FILE`, `tail -f /var/log/messages`	Show last lines or monitor file in real time	man page
`sort`	`sort FILE`	Sort file content (supports `-n`, `-u`)	man page
`uniq`	`uniq FILE`	Remove adjacent duplicate lines	man page
`file`	`file FILE`, `file data.txt`	Identify file type	man page
`cp`	`cp SRC DEST`, `cp /root/file /tmp/`	Copy files or directories	man page
`mv`	`mv old new`, `mv /root/file /tmp/`	Move or rename files	man page
`grep`	`grep STRING FILE`, `grep ssh /etc/services`	Search text in files	man page
`mkdir`	`mkdir DIR`	Create directory	man page
`touch`	`touch FILE`	Create empty file	man page
`pwd`	`pwd`	Show current directory	man page

Finding files and directories

Most of the time we will end up using find command to find files and directories. But I also like which command as it gives is the path of the binary which is required at multiple events when we are required to execute a binary with complete PATH.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`which`	`which cmd`, `which useradd`	Show full path of executable from `$PATH`	man page
`whereis`	`whereis cmd`, `whereis sshd`	Locate binary, source, and man pages	man page
`locate`	`locate file`, `locate sshd`	Fast search using indexed database	man page
`find`	`find / -name file`, `find / -type f -name sshd`	Search files in real-time with filters	examples

Check User Information

Recommended Read:

These are some of the commands which we use to check the last logged in user information and some other commands to get more details on existing user.

Command	Example / Syntax	Purpose	More details
`who`	`who -u`	Show logged-in users with session details	man page
`users`	`users`	List usernames currently logged in	man page
`last`	`last -a`	Show login/logout history from `/var/log/wtmp`	man page
`finger`	`finger`	Display user information (if installed)	man page
`whoami`	`whoami`	Show current logged-in user	man page
`id`	`id`	Display UID, GID, and groups	man page
`w`	`w`	Show logged-in users and their activity	—

Check System Information

As a sytem and Linux administrator you must be familiar with these commands. These will help you determine the type of server you are working on, such as load, cpu model, hardware model, hardware type etc. Some of the commands may be distribution specific such as hwinfo is only available in SuSE Linux while others are expected to be found on almost all distros.

Recommended Read:

Command	Example/Syntax	Comments	For more details
uptime	`uptime`	The `uptime` utility displays the current time, system uptime, number of logged-in users, and load averages (1, 5, and 15 minutes).	man page
free	`free -m`	The `free` utility shows total, used, and free physical (RAM) and swap memory, including kernel buffers.	Linux Memory Management
dmidecode	`dmidecode -t system`	`dmidecode` displays hardware information such as system serial numbers, BIOS details, and firmware information including BIOS revision.	man page
lshw	`lshw`	`lshw` extracts detailed hardware configuration including memory, firmware, CPU, cache, and bus speed.	man page
hwinfo	`hwinfo`	`hwinfo` probes system hardware and generates detailed reports (commonly available on SUSE systems).	man page
lscpu	`lscpu`	`lscpu` gathers CPU architecture information from sysfs, `/proc/cpuinfo`, and architecture-specific libraries.	man page
lspci	`lspci`	`lspci` displays information about PCI buses and connected devices.	man page
/proc/cpuinfo	`cat /proc/cpuinfo`	Provides detailed CPU information such as model, architecture, and processor details. This file is also used by `lscpu`.	man page
uname	`uname [OPTIONS]`	Prints system information such as kernel name, version, and architecture.	man page

Manage System Processes

These Linux commands will help you manage the Linux processes, and will help you troubleshoot any server resource related issues. You can use these commands to monitor your server's resource such as Memory, CPU, disk IO etc.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`ps`	`ps`, `ps aux`	Display running processes	man page
`nice`	`nice -n 10 command`	Start process with adjusted priority	example
`renice`	`renice -n 15 PID`	Change priority of running process	example
`top`	`top`	Real-time system and process monitoring	examples
`pgrep`	`pgrep process`	Find process IDs by name	man page
`pkill`	`pkill process`	Kill processes by name	man page
`kill`	`kill PID`, `kill -9 PID`	Send signal to process (terminate/force kill)	man page
`sar`	`sar -u 1 5`	Monitor system performance over time	examples
`vmstat`	`vmstat 1`	Show memory, CPU, and process stats	man page
`iostat`	`iostat -x`	Monitor disk I/O performance	man page
`crond`	`crontab -e`	Schedule jobs using cron daemon	examples

Managing Users and Groups

These are some of the basic Linux commands to perform user management such as create, modify, delete user or groups.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`useradd`	`useradd USER`	Create a new user account with default settings	examples
`usermod`	`usermod OPTIONS USER`, `usermod -G admin deepak`	Modify user account (e.g. add to group)	man page
`userdel`	`userdel USER`	Delete a user account	man page
`passwd`	`passwd USER`	Set or update user password, lock/unlock account	examples
`groupadd`	`groupadd GROUP`	Create a new group	examples
`groupdel`	`groupdel GROUP`	Delete a group	examples
`groupmod`	`groupmod OPTIONS GROUP`, `groupmod -n administrator admin`	Modify group (e.g. rename group)	examples
`sudo`	`$ sudo COMMAND`, `$ sudo systemctl network restart`	Run commands with elevated privileges	guide

Managing Permissions

Linux permission is a very vast topic and here I have only covered the basic commands which we use to assign/modify/remove permissions to files and directories.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`chown`	`chown USER:GROUP FILE`, `chown deepak:admin /tmp/file`	Change file owner and group	man page
`chmod`	`chmod PERM PATH`, `chmod 755 /tmp/dir1`	Change file permissions (symbolic or octal)	man page
`chgrp`	`chgrp GROUP FILE`, `chgrp admin /tmp/file`	Change group ownership	man page
`groups`	`groups USER`, `groups deepak`	Show groups of a user	man page
`newgrp`	`$ newgrp GROUP`, `$ id`	Change current primary group	man page
`setfacl`	`setfacl -m u:user:perm FILE`, `setfacl -m u:deepak:rx /tmp/file`	Set ACL permissions for users/groups	examples
`getfacl`	`getfacl FILE`, `getfacl /tmp/file`	View ACL permissions	examples
`chattr`	`chattr +i FILE`, `chattr +i /tmp/file`	Change file attributes (e.g. immutable)	examples
`lsattr`	`lsattr FILE`, `lsattr /tmp/file`	View file attributes set by `chattr`	examples

Configure and Troubleshoot Network

This section will help Network engineers who are new to Linux environment. I have tried to place the most used commands for network troubleshooting, we also have tcpdump, iperf, netperf and many other networking tools which are used for troubleshooting network related issues but they can get complicated hence those are not mentioned in this list.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`ifconfig`	`ifconfig`	Legacy tool to display network interfaces (use `ip addr` instead)	man page
`ip`	`ip addr`, `ip link show`	Modern tool to manage IP, interfaces, and network settings	examples
`route`	`route`	Legacy routing tool (use `ip route`)	ip route
`ip route`	`ip route`, `ip route show`	View and manage routing table	examples
`ethtool`	`ethtool DEVICE`, `ethtool -i eth0`	Display and modify NIC settings	man page
`ping`	`ping HOST`, `ping 192.168.0.100`	Test network connectivity	man page
`traceroute`	`traceroute HOST`, `traceroute 192.168.0.100`	Trace route to destination host	man page
`nmap`	`nmap HOST`	Scan open ports and services	man page
`netstat`	`netstat`, `netstat -tunlp`	Show network connections and ports (legacy, use `ss`)	man page
`nmcli`	`nmcli`	Command-line tool for NetworkManager	examples
`nmtui`	`nmtui`	Text-based UI for NetworkManager	examples
`ss`	`ss`, `ss -tunlp`	Display socket statistics (modern replacement for netstat)	man page

Managing Partitions and Logical Volumes

One of the primary roles of system administrator would be to configure partitions, storage layouts in the Linux server. Here you can get the list of most used Linux commands for managing partitions and file systems.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`df`	`df`	Show disk space usage of mounted filesystems	man page
`fdisk`	`fdisk DEVICE`	Manage disk partitions (MBR/GPT)	example
`cfdisk`	`cfdisk DEVICE`	Interactive partition table editor	man page
`parted`	`parted`	Advanced partition management tool (GPT/MS-DOS)	example
`pvcreate`	`pvcreate DEVICE`, `pvcreate /dev/sda`	Create LVM physical volume	example
`pvdisplay`	`pvdisplay DEVICE`	Show physical volume details	man page
`pvs`	`pvs`	Display summary of physical volumes	man page
`vgcreate`	`vgcreate VG PV`, `vgcreate test_vg /dev/sda`	Create volume group	example
`vgdisplay`	`vgdisplay`	Show volume group details	man page
`vgs`	`vgs`	Display summary of volume groups	man page
`lvcreate`	`lvcreate OPTIONS`, `lvcreate -L 1G -n lv vg`	Create logical volume	example
`lvdisplay`	`lvdisplay`	Show logical volume details	man page
`lvs`	`lvs`	Display summary of logical volumes	man page
`pvscan`	`pvscan`	Scan and detect physical volumes	example
`vgscan`	`vgscan`	Scan and detect volume groups	man page
`lvscan`	`lvscan`	Scan and detect logical volumes	man page
`vgchange`	`vgchange -ay`	Activate/deactivate volume groups	example
`e2fsck`	`e2fsck DEVICE`	Check and repair ext filesystems	example
`tune2fs`	`tune2fs DEVICE`	Modify filesystem parameters	example
`dumpe2fs`	`dumpe2fs DEVICE`	Show filesystem metadata and superblock	man page
`mkfs`	`mkfs.ext4`, `mkfs.xfs`	Create filesystem on device	example
`lvextend`	`lvextend OPTIONS`	Extend logical volume size	example
`vgextend`	`vgextend VG PV`	Add physical volume to volume group	example
`resize2fs`	`resize2fs DEVICE`	Resize ext filesystem	example
`lsscsi`	`lsscsi`	List SCSI devices	man page
`lsblk`	`lsblk`	Show block devices and hierarchy	man page
`blkid`	`blkid`	Display UUID of block devices	man page

Managing RPM and Software Repositories

With package manager such as yum, dnf, apt-get, the life of a system administrator becomes very easy. You can easily install, update, remove packages, upgrade server operating system and much more using these commands.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`rpm`	`rpm -ivh pkg.rpm`, `rpm -qa`	Install, query, and manage RPM packages	man page
`yum`	`yum install pkg`	Legacy package manager for RPM systems (replaced by `dnf`)	examples
`dnf`	`dnf install pkg`	Modern package manager for RPM-based systems	examples
`yumdownloader`	`yumdownloader pkg`	Download RPM packages without installing	examples
`zypper`	`zypper install pkg`	Package manager for SUSE-based systems	examples
`apt-get`	`apt-get install pkg`	Package manager for Debian/Ubuntu systems	man page
`apt-cache`	`apt-cache search pkg`	Search packages from local cache	man page
`dpkg`	`dpkg -i pkg.deb`	Install and manage Debian packages	man page
`dpkg-scanpackages`	`dpkg-scanpackages dir`	Create repository metadata from `.deb` files	man page
`createrepo`	`createrepo /repo`	Create YUM/DNF repository metadata	examples
`repoquery`	`repoquery pkg`	Query package info from repositories	examples
`repotrack`	`repotrack pkg`	Download package with dependencies	examples
`reposync`	`reposync`	Sync remote repository locally	examples
`subscription-manager`	`subscription-manager status`	Manage RHEL subscriptions and repositories	examples

Manage logging

Now you know about most of the Linux commands to manager different areas of Linux server but you must be familiar of how logging works in Linux? This may vary based on different distribution, with old distros we used syslog-ng for logging but now almost all major distros have moved to rsyslog solution.

Recommended Read:

Command	Example / Syntax	Purpose	More details
`logger`	`logger "message"`	Write messages to system logs	examples
`logrotate`	`logrotate -f /etc/logrotate.conf`	Rotate and manage log files to prevent growth	examples
`journalctl`	`journalctl`, `journalctl -xe`	View and filter systemd journal logs	examples

Conclusion

In this cheat sheet tutorial I have tried to consolidate most used Linux commands by different types of experts across IT domains. I am yet to add commands for many other scenarios such as Managing Linux services, archiving, firewall etc but that would just make this tutorial infinite long. I may write another article based on the response I get on this one, even writers need motivation. So that I know people are reading and loving this cheat sheet then I may decide to spend some more time to write about the remaining Linux commands in another tutorial.

Looking forward for your feedback in the comment section.