Linux Commands Cheat Sheet

Last updated: June 17, 2022

Here in this cheat sheet, Linux commands are categorized into different sections according to its usage. It is designed with all the commands in a nice background color.

You will find both the pdf and image (png) format of the cheat sheet.

Cheat sheet

Download your Linux commands cheat sheet in pdf format and print the Linux command download cheat sheet in A4 size paper.

Please keep us posted if you have any suggestions or if you find any command that we missed out on.

Linux Commands Cheat Sheet

1. System Based Commands

uname  Displays  Linux system information
uname -rDisplays  kernel release information
uptimeDisplays how long the system has been running including load average
hostnameShows the system hostname
hostname -iDisplays the IP address of the system
last rebootShows system reboot history
dateDisplays current system date and time
timedatectlQuery and change the System clock
calDisplays the current calendar month and day
wDisplays currently  logged in users in the system
whoamiDisplays who you are logged in as
finger usernameDisplays information about the user

2. Hardware Based Commands

dmesgDisplays bootup messages
cat /proc/cpuinfoDisplays more information about CPU e.g model, model name, cores, vendor id
cat /proc/meminfoDisplays more information about hardware memory e.g. Total and Free memory
lshwDisplays information about system's hardware configuration
lsblkDisplays block devices related information
free -mDisplays free and used memory in the system (-m flag indicates memory in MB)
lspci -tvDisplays PCI devices in a tree-like diagram
lsusb -tvDisplays USB devices in a tree-like diagram
dmidecodeDisplays hardware information from the BIOS
hdparm -i /dev/xdaDisplays information about disk data
hdparm -tT /dev/xda <:code>Conducts a read speed test on device xda
badblocks -s /dev/xdaTests  for unreadable blocks on disk

3. Users Management Commands

idDisplays the details of the active user e.g. uid, gid, and groups
lastShows the last logins in the system
whoShows who is logged in to the system
groupadd "admin" Adds the group 'admin'
adduser "Sam" Adds user Sam
userdel "Sam"Deletes user Sam
usermodUsed for changing / modifying user information

4. File Commands

ls -alLists files - both regular &  hidden files and their permissions as well.
pwdDisplays the current directory file path
mkdir 'directory_name'Creates a new directory
rm file_name Removes a file
rm -f filenameForcefully removes a file
rm -r directory_nameRemoves a directory recursively
rm -rf directory_nameRemoves a directory forcefully and recursively
cp file1 file2Copies the contents of file1 to file2
cp -r dir1 dir2Recursively Copies dir1 to dir2. dir2 is created if it does not exist
mv file1 file2Renames file1 to file2
ln -s /path/to/file_name   link_nameCreates a symbolic link to file_name
touch file_nameCreates a new file
cat > file_namePlaces standard input into a file
more file_nameOutputs the contents of a file
head file_nameDisplays the first 10 lines of a file
tail file_nameDisplays the last 10 lines of a file
gpg -c file_nameEncrypts a file
gpg file_name.gpgDecrypts a file
wcPrints the number of bytes, words and lines in a file
xargsExecutes commands from standard input

5. Process Related Commands

psDisplay currently active processes
ps aux | grep 'telnet'Searches for the id of the process 'telnet'
pmapDisplays memory map of processes
top Displays all running processes
kill pidTerminates process with a given pid
killall procKills / Terminates all processes named proc
pkill process-nameSends a signal to a process with its name
bgResumes suspended jobs in the background
fgBrings suspended jobs to the foreground
fg n job n to the foreground
lsofLists files that are open by processes
renice 19 PIDmakes a process run with very low priority
pgrep firefoxfind Firefox process ID
pstreevisualizing processes in tree model

6. File Permission Commands

chmod octal filename         Change file permissions of the file to octal
  
Example 
chmod 777 /data/test.c       Set rwx permissions to owner, group and everyone (everyone else who has access to the server)
chmod 755 /data/test.c       Set rwx to the owner and r_x to group and everyone
chmod 766 /data/test.c       Sets rwx for owner, rw for group and everyone
chown owner user-file         Change ownership of the file
chown owner-user:owner-group file_name       Change owner and group owner of the file
chown owner-user:owner-group directory  Change owner and group owner of the directory

7. Network Commands

ip addr show                   Displays IP addresses and all the network interfaces
ip address add 192.168.0.1/24 dev eth0    Assigns IP address 192.168.0.1 to interface eth0
ifconfig                             Displays IP addresses of all network interfaces
ping  host                       ping command sends an ICMP echo request to establish a connection to server / PC
whois domain                  Retrieves more information about a domain name
dig domain                       Retrieves DNS information about the domain
dig -x host                    Performs reverse lookup on a domain
host google.com          Performs an IP lookup for the domain name
hostname -i                     Displays local IP address
wget file_name             Downloads a file from an online source
netstat -pnltu     Displays all active listening ports

8. Compression/Archives Commands

tar -cf home.tar home<:code>Creates archive file called 'home.tar' from file 'home'
tar -xf files.tar              Extract archive file 'files.tar'
tar -zcvf home.tar.gz source-folder    Creates gzipped tar archive file from the source folder
gzip file Compression a file with .gz extension

9. Install Packages Commands

rpm -i pkg_name.rpm            Install an rpm package
rpm -e pkg_name                     Removes an rpm package
dnf install pkg_nameInstall package using dnf utility

10. Install Source (Compilation)

./configureChecks your system for the required software needed to build the program. It will build the Makefile containing the instructions required to effectively build the project
makeIt reads the Makefile to compile the program with the required operations. The process may take some time, depending on your system and the size of the program
make installThe command installs the binaries in the default/modified paths after the compilation

11. Search Commands

grep 'pattern' files                           Search for a given pattern in files
grep -r pattern dir                             Search recursively for a pattern in a given directory
locate file                                            Find all instances of the file
find /home/ -name "index"              Find file names that begin with 'index' in /home folder
find /home -size +10000kFind files greater than 10000k in the home folder

12. Login Commands

ssh [email protected]                                        Securely connect to host as user
ssh -p port_number [email protected]      Securely connect to host using a specified port
ssh host                                                Securely connect to the system via SSH default port 22
telnet host Connect to host via telnet default port 23

13. File Transfer Commands

scp file1.txt server2/tmp           Securely copy file1.txt to server2 in /tmp directory
rsync -a /home/apps  /backup/ Synchronize contents in /home/apps directory with /backup  directory

14. Disk Usage Commands

df  -h                           Displays free space on mounted systems
df  -i                          Displays free inodes on filesystems
fdisk  -l                    Shows disk partitions, sizes, and types
du  -sh                        Displays disk usage in the current directory in a human-readable format
findmnt                      Displays target mount point for all filesystems
mount device-path mount-pointMount a device

15. Directory Traverse Commands

cd ..             Move up one level in the directory tree structure
cd                 Change directory to $HOME directory
cd /test Change directory to /test directory

About The Author

Bobbin Zachariah

Bobbin Zachariah

Bobbin started his career in IT in the year 2000 as a computer science instructor and worked as a Linux system engineer and senior analyst roles. Currently working in DevOps environments to increase efficiency and improve delivery time in AWS Cloud infrastructure. He is certified in RHEL, CCNA, and MCP and holds a Masters's in computer science. When in his free time love playing cricket, blogging, and listening to music.

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