Bash one line port scanner using nc

scan.bash

# Creates 993 nc processes. Returns in about 1 minute max
ip=127.0.0.1
b(){ for i in {0..992};do nc $ip -w1 -vz $((i*66+1))-$((i*66+66>65535?65535:i*66+66)) 2>&1|egrep 'open|succeed'&done;wait;} 2>/dev/null;b

Caveats:

• 1 second timeout, if a legitimate port takes >1s to return leads to false negative
• 1000 nc processes created, you can tweak 992 and 66 above to wait longer with less processes