pwd : print working directory
pwd
cd : Change directory
cd Desktop
ls : list files & directories
ls , ls -l , ls -la
touch : create file
touch hello.txt
cat : list content in file and join them
cat file1 , cat file1 file2 > file3
echo : print statement
echo "Hello"
cp : copy file
cp test1.txt ./Desktop/files/test2.txt
mv : move file
mv test1.txt ./Desktop/files
mkdir : make directory
mkdir test , mkdir -p test1/test2/test2
rm : remove file
rm test.txt , rm -r directory
locate : find location of file
locate test*
find : find location of file in given directory
find test*
grep : show lines that consists word
grep "hello" file.txt , grep "hello"
df : report on the system\'s disk space use
df , df -m
du : disk usage shown in blocks
du , du -h , du -sh
free : check RAM usage
free , free -h
diff : compare contents of two files and display difference
diff file.txt test.txt
tar : convert into tarball or zip basically archiving
tar < options > files
zip : to zip files
zip files
unzip : to unzip files
zip file.zip
gzip : to zip files
gzip files
gunzip : to unzip files
gzip file.zip
sort : sort list
sort file.txt
uniq : show unique words
uniq file.txt
wc : word count
wc file.txt , wc -l file.txt
scp : opensssh secure shell file copy
scp file.txt
cut : cut strings
cut -d "-" -f 2
ln : link for file
ln test.txt , ln -s test.txt
strings : sequence of printable characters in files
strings data.txt
gpg : encrypt and decrypt file
gpg file.txt.gpg , gpg file.txt
tac : reverse print file
tac file.txt > reverse.txt
stat : Information about file
stat file.txt
tr : translate
cat file.txt | tr -s '[a-z]' '[A-Z]'
head : view starting n lines of files
head file.txt , head -n 10 file.txt
tail : view last n line of file
tail file.txt , tail -n 10 file.txt
vi : vim editor
vi file.txt
nano : nano editor
nano file.txt
chmod : change permission of files (ls -la for permissions)
chmod ugo+rwx file.txt , chmod ugo-rwx file.txt , chmod 777 file.txt
chown : change ownership of file
chown root(user) file.tar
chgrp : change group ownership
jobs : current jobs along with status
jobs
top : show running tasks i.e. linux task manager
top
kill : kill process using PID from top
kill 123455 , kill -9(SIGTERM) PID , kill -15(SIGKILL) PID
ps : return running process status
ps , ps aux
fg : get process to foreground
fg id
bg : get process in background
bg
systemctl : start , stop or check status of service
systemctl start ssh
journalctl : logs about service
journalctl -u ssh.service
service : run a System V init script
service name start , service tor stop
xargs : pass list as input
cat filenames.txt | xargs rm
uname : Unix name , details about system
uname , uname -a , uname -r
useradd : add users
useradd user
userdel : delete user
userdel Username , userdel -r username
usermod : Modifies a user account , add user to group
usermod user
passwd : change password
passwd
whoami : displays username
whoami
who : currently logged in users
who
groups : check which group user belongs to
groups root , groups user
groupadd : add group
groupadd group_name
id : returns user identity
id
hostname : name of host i.e. user
hostname , hostname -i
env : prints environment or sets and executes command
env
chsh : change login shell
chsh
sudo : super user do
sudo -s , sudo apt-get install python3
su : change user in shell , switch user
su user
visudo : sudoers list can be edited
visudo
man : manual page
man nmap , man ls
apropos : description about tools
apropos sudo
whatis : simple description
whatis cd
clear : clear terminal window
clear / ctrl + l
history : shows commands that you ran
history
lsblk : Lists block devices.
lsblk
lsusb : Lists USB devices
lsusb
lsof : Lists opened files.
lsof
lspci : Lists PCI devices.
lspci
dpkg : The dpkg is a tool to install, build, remove, and manage Debian packages. The primary and more user-friendly front-end for dpkg is aptitude.
apt : Apt provides a high-level command-line interface for the package management system.
aptitude : Aptitude is an alternative to apt and is a high-level interface to the package manager.
snap : Install, configure, refresh, and remove snap packages. Snaps enable the secure distribution of the latest apps and utilities for the cloud, servers, desktops, and the internet of things.
gem : Gem is the front-end to RubyGems, the standard package manager for Ruby.
pip : Pip is a Python package installer recommended for installing Python packages that are not available in the Debian archive. It can work with version control repositories (currently only Git, Mercurial, and Bazaar repositories), logs output extensively, and prevents partial installs by downloading all requirements before starting installation.
git : Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
; ls ; pwd Even with errors all commands run independently
&& ls && pwd Stop if error i.e all commands are related
| ls | pwd depends upon previous process and error free execution