Add option to use nc (netcat) instead o bash /dev/tcp/

[evandrocoan]

I was using to use this script (which used (echo -n > /dev/tcp/$WAITFORIT_HOST/$WAITFORIT_PORT) >/dev/null 2>&1 hack on a old operating system/bash 3.2.39), but it was not working, i.e., detecting the when the connection was open. When, I forced the script to use nc -z alternative and it started working.

[le-shi]

I also encountered a similar problem. Some security products of public cloud platforms would identify (echo -n > /dev/tcp/$WAITFORIT_HOST/$WAITFORIT_PORT) >/dev/null 2>&1 as horizontal penetration, which resulted in my inability to use it. I could only complete the original work by using nc command.