System Management:

`ps`: Display running processes.
`top`: Monitor system processes and resource usage.
`kill`: Terminate a running process.
`shutdown`: Shutdown or restart the system.
`reboot`: Restart the system.
`df`: Display disk space usage.
`free`: Display memory usage.
`uname`: Display system information.
`chmod`: Change file permissions.
`chown`: Change file ownership.
`sudo`: Execute commands with superuser (root) privileges.



`ping`: Send ICMP echo requests to a specified host.
`ifconfig`: Display network interface configuration.
`ip`: Show/manipulate routing, devices, policy routing, and tunnels.
`ssh`: Connect to a remote server using the Secure Shell (SSH) protocol.
`scp`: Securely copy files between local and remote systems.
`wget`: Download files from the web.
`curl`: Transfer data from or to a server using various protocols (HTTP, FTP, etc.).
`netstat`: Display network connections, routing tables, and interface statistics.
`traceroute`: Print the route packets take to a network host.
`nc`: Utility for reading/writing data across network connections.


Text Processing:

`grep`: Search for patterns in files.
`sed`: Stream editor for text manipulation.
`awk`: Text processing language for extracting data and generating reports.
`sort`: Sort lines in a file.
`cut`: Extract specific columns or fields from a file.
`wc`: Count lines, words, and characters in a file.
`uniq`: Remove duplicate lines from a file.
`tee`: Read from standard input and write to files and standard output simultaneously.


Package Management:

`apt-get`: Package handling utility for Debian-based systems.
`yum`: Package manager for RPM-based systems.
`dnf`: Next-generation package manager, an alternative to `yum`.