Exactly Seph, but you have to define $IP if you are going to use that. $1, $2, $3, $4, etc. are all predefined variables and is the same as sys.argv[1], sys.argv[2], sys.argv[3], sys.argv[4], etc. If I am not entirely mistaken.

In PHP you would have to define $IP like:
$IP = sys.argv[1]; // afaik, this may be wrong.
system('clear');
$commandline = "nmap -sP $IP > /pentest/results/scans/$scanname.txt && echo scan complete."
system($commandline);

Now I know this about shell scripting, but since I don't know how to use getopts, even though it's fairly simple as I read the "manual" not long ago, I thought that I would use PHP instead as an example as most programming languages translates universally somewhat.

Awesome, good to hear you read the manpage and understood everything  It's understandable you don't want to dive into PHP or other scripting or programming languages at the moment, as it is easy to get lost if you dive into too many projects / languages at once. 

Good work.  Now keep going.  There's no end to what you can script up, during a pentest, and more often than not, you don't have tons of time to do it, so practice, practice, practice, and get proficient at it.

Try chaining tools and output together (calling one tool with output from another), reading from input / output files, etc.  Keep building on what you've accomplished, and you'll grow by leaps and bounds.

(And for your own benefit, learn to comment in your scripts, so you can reference them later, if you've forgotten something, or need a quick reminder.)