linux.md

layout	title
../../layouts/CheatSheet.astro	Linux Cheatsheet

Synopsis

Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged in a Linux distribution.

Basic System Commands

Command	Description
exit	Close / exit from a from terminal
xkill	After right click on any window to close
poweroff	Turn off the system using terminal
reboot	Restart the system using terminal

File Commands

Command	Description
ls	List files in current directory
ls -l	List files in long format
ls -a	List all files including hidden files
pwd	Print working directory
cd	Change directory
cd ..	Change directory to parent directory
cd ~	Change directory to home directory
cd -	Change directory to previous directory
mkdir	Create directory
mkdir -p	Create directory and parent directories
touch	Create file
cp	Copy file
cp -r	Copy directory
mv	Move file
mv -r	Move directory
rm	Remove file
rm -r	Remove directory
rm -f	Force remove file
rm -rf	Force remove directory

File Permissions

Command	Description
chmod	Change file permissions
chmod 777	Change file permissions to 777
chmod u+x	Change file permissions to executable for user
chmod g+x	Change file permissions to executable for group

Privilege Escalation

Command	Description
sudo -l	List sudo permissions
sudo -u	Run command as another user
sudo -i	Run shell as another user
sudo !!	Run previous command as root
su	Run shell as another user

SSH

Command	Description
ssh user@host	Connect to remote host
ssh -p port user@host	Connect to remote host on specific port
ssh-copy-id	Copy SSH key to remote host
ssh-keygen	Generate SSH key

System Info

Command	Description
uname	Print system information
uname -a	Print all system information
uname -r	Print kernel release
uname -m	Print machine hardware name
hostname	Print system hostname
hostname -I	Print all IP addresses
hostname -i	Print IP address
date	Print system date and time
cal	Print calendar
uptime	Print system uptime
whoami	Print current user
w	Print who is logged in
finger	Print information about user
id	Print effective user and group id
groups	Print all groups current user is in
last	Print last logged in users
lastlog	Print when users last logged in
free	Print free and used memory
df	Print disk usage
du	Print file space usage
du -h	Print file space usage in human readable format
man	Print manual page (exit with q)
top	Get all running procsee & hardware consumptions

Shortcuts

Command	Description
Ctrl + a	Go to the beginning of the line you are currently typing on
Ctrl + e	Go to the end of the line you are currently typing on
Ctrl + u	Clear the line before the cursor position. If you are at the end of the line, clears the entire line.
Ctrl + k	Clear the line after the cursor position. If you are at the beginning of the line, clears the entire line.
Ctrl + w	Delete the word before the cursor.
Ctrl + r	Let you search through previously used commands.
Ctrl + l	Clears the Screen, similar to the clear command.
Ctrl + c	Kill whatever you are running.
Ctrl + d	Exit the current shell.
Ctrl + z	Puts whatever you are running into a suspended background process. fg restores it.
Ctrl + s	Stop output to the screen (for long running command).
Ctrl + q	Allow output to the screen (for long running command).
Ctrl + x	Use the arrow keys to navigate through the command line history.
Ctrl + _	Undo.
Ctrl + Alt + T	Open terminal using keyboard
Ctrl + Shift + N	Open new terminal window
Ctrl + Shift + T	Open new tab in terminal
Ctrl + Shift + C	Copy selected text from terminal
Ctrl + Shift + V	Paste any coppied text in terminal

// Also press up & down arrow respectively to get the former & latter executed commands in a terminal .

Text Editors

Command	Description
nano	Nano is a simple text editor for Unix-like computer operating systems.
vim file	Vim is a highly configurable text editor built to enable efficient text editing.
vi file	Vi is a screen-oriented text editor originally created for the Unix operating system.
emacs file	Emacs is a family of text editors that are characterized by their extensibility.

Archives

Command	Description
tar -xvf file.tar	Extract tar file
tar -cvf file.tar directory	Create tar file
tar -tvf file.tar	List contents of tar file
tar -xvzf file.tar.gz	Extract tar.gz file
tar -cvzf file.tar.gz directory	Create tar.gz file
tar -tvzf file.tar.gz	List contents of tar.gz file
tar -xvjf file.tar.bz2	Extract tar.bz2 file
tar -cvjf file.tar.bz2 directory	Create tar.bz2 file
tar -tvjf file.tar.bz2	List contents of tar.bz2 file
unzip file.zip	Extract zip file
zip file.zip directory	Create zip file
zip -r file.zip directory	Create zip file recursively
unrar x file.rar	Extract rar file
rar a file.rar directory	Create rar file

Disk Usage

Command	Description
df	Show disk usage
du	Show file space usage
du -h	Show file space usage in human readable format
du -a	Show file space usage for all files
du -s	Show summarized file space usage
du -sh	Show summarized file space usage in human readable format
du -c	Show summarized file space usage with grand total
fdisk -l	Show all disk partitions
fdisk /dev/sda	Show disk partitions for /dev/sda
mount	Show mounted filesystems

Search

Command	Description
grep pattern file	Search for pattern in file
grep -r pattern directory	Recursively search for pattern in directory
grep -v pattern file	Invert match, print non-matching lines
grep -l pattern file	Print only filenames with matches
grep -i pattern file	Ignore case distinctions
grep -r -i pattern directory	Recursively search for pattern in directory, ignoring case
locate file	Find file
find / -name file	Find file in /
find / -name file -type f	Find only files in /

Networking

Command	Description
ifconfig	Configure a network interface
ifconfig -a	Configure all network interfaces
ifconfig eth0	Configure eth0 network interface
iwconfig	Get information for WiFi adapters
nmcli networking off	Turn off network connections
nmcli networking on	Turn on network connections
systemctl stop NetworkManager	Turn off network connections
systemctl start NetworkManager	Turn on network connections
systemctl restart NetworkManager	Restart network connectionss
whois domain	Get whois information for domain
dig domain	Get DNS information for domain
dig -x host	Get DNS information for host
host domain	Get DNS information for domain
host -t mx domain	Get MX records for domain
hostname -I	Get all IP addresses
hostname -i	Get IP address

VIM

Command	Description
h	move cursor left
j	move cursor down
k	move cursor up
l	move cursor right
gg	go to the first line of the document
G	go to the last line of the document
zz	center cursor on screen
0	jump to the start of the line

Emacs

Command	Description
CTRL+O	Write the current file to disk
CTRL+X	Close the current file buffer / Exit from Nano
CTRL+R	Insert another file into the current one
ALT+<	Switch to the previous file buffer
ALT+>	Switch to the next file buffer
ALT+D	Count the number of words, lines, and characters
CTRL+L	Refresh (redraw) the current screen

Tree

Command	Description
tree	It will display the contents of the working directory recursively showing sub-directories and files
tree -a	Display also the hidden files
tree -f	Display contents with the full path prefix
tree -d	Display only the subdirectories
tree -df	Display subdirectories with their paths
tree -L 2	Specifying depth of the directory
tree -P init.py*	Display only those files that match the pattern
tree --du	Reports the size of each element
tree -J	Outputs the directory tree as an JSON formatted array
tree -o direc_tree.txt	Redirect the tree’s output to filename