Recently I had to rename maybe 20–30 files where I had to extract some fields from the file name, and then modify the numbers, like add 2000 to the number from the file, and change a few things in the file names. I gave a try to a few apps, but I was not happy how they were designed. A lot of buttons, a lot of options, a lot of configurations, felt like the time I would spend to learn how to use those apps will be similar to just write at the end a bash script.