Want to hammer a nail into a wall? Build a robot to do it! If you have lots of spare time, of course...
Do you need to process a list of 10,000 things, once a day, forever? Then you do need to automate.
Do you need to process a list of 100 things, once? Just roll up your sleeves and start typing (or get someone else to do it). The chances that you could come up with something remotely reusable in less than the two minutes it'd take to do manually are slim to none, yet I have often seen people spend a couple of hours coding up a script to do a 15 minute non-recurring job.
And when your awk script grows into something that doesn’t produce the final output, but has to be run in another interpreter first in order to produce the final result, then you created your custom language.
It’s not the thing you should do if you need to do it repeatedly, like once a day or even once a month.
This all depends on a lot of circumstances, and its hard to calculate time for implementing a script vs doing it by hand for a future you don’t know yet.
It's also possible to do partial automation, where you just automate what's easy and finish up manually.
I overnighted a book from amazon on the VCS and process management tools they were using, read it the following night, and the next day took about 15 minutes to talk to Tim and then another 30 minutes writing a perl script that prompted for the 4 bits of information they needed and automated the check-in and change-review request. Total billable time spent on this 45 minutes. Time saved by having this script around the 2 weeks I was with the customer at least 2 hours (10 minutes of my time were wasted every time a change needed to be submitted previously!).
Every time I visited that customer in the future, the group was still using that script I wrote. Also every time the manager wanted me to assure him I wouldn't waste time by writing a script like that because that's not what they were paying me for.
It eternally baffles me (although no longer, sadly, surprises me) how often this happens. Clear evidence of a simple change which dramatically improves efficiency and therefore profits, and someone complains and tries to prevent it ever happening again because "that wasn't what I specifically wanted to do right then."
Should've added the time spent on book to billable time (though I guess your manager would approve of that even less than they approve of scripts, given the description). In a few similar situations I've managed to get approval of my manager to bill the time I spent on such emergency learning, because let's be honest, I'm not speed-reading a book on an obscure piece of tech for fun.