Linux commands

• ls: Lists directory contents.

ls
ls -l
ls -a

• cd: Changes the current directory.

cd /path/to/directory
cd ..

• pwd: Prints the current working directory.
• mkdir: Creates a new directory.

mkdir directory_name

• rm: Removes files and directories.

rm file_name
rm -r directory_name

• cp: Copies files and directories.

cp file_name new_file_name
cp -r directory_name new_directory_name

• mv: Moves or renames files and directories.

mv file_name new_location/file_name
mv old_name new_name

• cat: Concatenates and displays file content.

cat file_name

• grep: Searches for patterns in files.

grep "pattern" file_name

• chmod: Changes the permissions of files and directories.

chmod 644 file_name
chmod +x script_name

• chown: Changes the ownership of files and directories.

chown user_name file_name
chown -R user_name directory_name

• ssh: Connects to a remote server via SSH.

ssh username@remote_host

• scp: Copies files between local and remote servers using SSH.

scp file_name username@remote_host:/remote/directory
scp username@remote_host:/remote/file_name /local/directory

• wget: Downloads files from the web.

wget https://example.com/file_name

• tar: Archives or extracts files.

tar -czvf archive.tar.gz directory_name
tar -xzvf archive.tar.gz

• ps: Displays the currently running processes.
• top: Shows real-time system resource usage.
• kill: Terminates processes.

kill process_id
killall process_name

• ping: Sends ICMP echo requests to test network connectivity.

ping hostname
ping IP_address

• ifconfig: Configures network interfaces (older command, replaced by ip command in newer distributions).

ifconfig
ifconfig eth0 up

• netstat: Displays network connections and statistics.

netstat -tuln
netstat -anp | grep LISTEN

• iptables: Manages firewall rules.

iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j ACCEPT

• systemctl: Controls system services (used in systemd-based distributions).

systemctl start service_name
systemctl stop service_name
systemctl restart service_name

• journalctl: Views system logs (used in systemd-based distributions).

journalctl -u service_name
journalctl -f

• sudo: Executes commands with administrative privileges.