First, is it all version controlled?
And are any of the files currently in editor buffers? Close if so.
There are two different versions of rename
the perl-rename that I was expecting
$ rename 's/monkey/reproducer/g' *monkey*
and the rename from util-linux 2.28.2 that's actually on my Fedora box
$ rename monkey reproducer *monkey*
need to do this in all affected directories, there's probably something you can do with find if there are lots
and then to change the text in all the files (recursive)
$ grep -rl monkey . | xargs sed -i 's/monkey/reproducer/g'
finally change it in .bash_history too
sed -i 's/monkey/reproducer/g' ~/.bash_history
note that this will corrupt the history of all the commands you just typed.