This one has me stumped :-/
I have a non-rooted nexus 7 (2013, Android 4.4.2). There is a directory on the inbuilt sd card and this directory has about 200 files in and I would like to rename each file in this directory to what you would get if you rot13 the file!
$ for i in * ; do j=`echo $i | rot13`; mv "$i" "$j"; done
would do it on a unix machine with rot13 installed. I have Android Terminal Emulator and BusyBox Non-Root installed but unfortunately neither seem to have a rot13 command.