I'm not certain that these are the ones that are executed when I type get_iplayer in the terminal.

The command "which get_iplayer" will show you which executable gets run when you type "get_iplayer" in the terminal.

Are there any Perl scripts associated with the get_iplayer_web_pvr command that require to be modified to use the system version of Perl?

By googling I can only guess that get_iplayer_web_pvr is from the Debian get-iplayer package, its source is nice and short:

#!/bin/sh
. /etc/default/get_iplayer_web_pvr
/usr/bin/perl /usr/share/get_iplayer/get_iplayer.cgi -p $PORT -g /usr/
+bin/get_iplayer -l $LISTEN
[download]

Which would mean that the answer to your question is no, no changes to that script are necessary. Plus, since the get_iplayer.cgi script is being specifically invoked with the system Perl at /usr/bin/perl, you might not even have to modify get_iplayer.cgi, although it wouldn't hurt.

OK, I'm now well beyond my knowledge of what is happening so please bare with me!

"which get_iplayer" returns /usr/local/bin/get_iplayer

When I look in this folder get_iplayer is shown as an "alias" that contains the following:

"/usr/local/cellar/get_iplayer/3.01.0/bin/get_iplayer; exit;"

There is also an alias for "get_iplayer_web_pvr" which points to the same folder as above. The "get_player" and "get_iplayer_web_pvr" files that are contained in the "/usr/local/cellar/get_iplayer/3.01.0/bin" folder are both listed as unix executables by Finder. Do these executables call the Perl scripts? If so, where the Perl scripts that I need to modify to use the system version of Perl?

I'm afraid that I'm way out of my depth in trying to figure out what is happening. Any assistance that you can provide would be greatly appreciated!

The command-line program file should be useful here. Try "file /usr/local/cellar/get_iplayer/3.01.0/bin/get_iplayer" - if it shows you something like "Perl script, ASCII text executable", you can go ahead and open that file in a plain-text editor of your choice (not Word or other rich-text editors - I believe the standard TextEdit should be fine, see Tools for OSX). If it shows you something like "symbolic link to filename", you'll have to follow the chain a bit further and do file filename, and so on. In the unlikely case that it shows you some kind of binary file format instead of ASCII, please post that here.