#Navigation
pwd → Prints the current working directory.
cd → To change the current working directory.
cd .. → To move one directory back.
ls → Lists the contents of a directory.
ls -la → To show hidden files.
#System Info.
whoami → Displays the current user.
uname → Displays system info.
hostname → Display or set system’s hostname.
#File system info.
df → To check the file system disk space usage.
free → Displays system memory usage.
du → Displays the file/dir space usage.
#File/Dir operations
echo → To print anything.
touch → Creates a new empty file.
mkdir → Creates a directory.
vi/vim → Edits the content of file.
cat → To read the content of file.
read → Waits for user input.
sudo → To give administrator permissions.
mount → To mount a file system.
chown → To change the ownership of a file/directory.
chmod → To change permissions of file/directory.
chgrp → To change the group ownership of a file/directory.
rm → To delete a file.
rm -rf → To Remove directories and content recursively.
rmdir → To delete a directory.
mv oldname newname → To rename file/directory.
cp source destination → To copy file/dir from source to destination location.
mv source destination → To move file/dir from source to destination location.
grep → To search for something specific in a file.
awk → To extract specific fields from a file.
find → To fi nd file/directory.
sed → To search for patterns in a text.
head → To print the first n no. of lines of a file.
tail → To print the last n no. of lines of a file.
tar → Used to create Archive and extract the Archive files.
#Local to Remote connection
scp → To securely copy files between two machines.
ssh → To securely log into a remote machine.
#Process Management
ps → Displays info about processes.
top → Displays top running processes.
kill → To terminate a process.
pkill → To kill the process by its name.
#User Management
useradd → To add a new user.
userdel → To remove an existing user.
groupadd → To add a new group.
#ACL commands
getfacl → For getting detailed permission of a file.
setfacl → For setting up ACL.
#Networking
ping → Checks network connectivity.
traceroute → Trace a route to a host.
ifconfig → Config network interfaces.
netstat → Display network connections.
iptables → Configure firewall rules.
*👆The information presented above is based on my interpretation. Suggestions are always welcome.*😊
~Smriti Sharma✌