ping: Check network connectivity.

• Example: ping google.com

curl: Transfer data from or to a server.

• Example: curl https://example.com

wget: Download files from the web.

• Example: wget https://example.com/file.zip

ssh: Securely access remote servers.

• Example: ssh user@hostname

scp: Securely copy files to/from a remote server.

• Example: scp file.txt user@hostname:/destination