AWK, SED, REGEX to rename files

Question

I'm only learning to use REGEX, AWK and SED. I currently have a group of files that I'd like to rename - they all sit in one directory.

The naming pattern is consistent, but I would like to re-arrange the filenames, here is the format:

01._HORRIBLE_HISTORIES_S2.mp4
02._HORRIBLE_HISTORIES_S2.mp4

I'd like to rename them to HORRIBLE_HISTORIES_s01e01.mp4 - where the e01 is gleaned from the first column. I know that I want to grab "01" from the first column, stuff it in a variable then paste it after the S2 in each filename, at the same time I want to remove it from the beginning of the filename along with the "._", additionally I want to change the "S2" to "s02".

If anyone would be so kind, could you help me write something using awk/sed and explain the procedure, that I might learn from it?

Answer 1

using AWK. rename file with first and second and 4th part

ls | while read file; do newfile=`echo $file | awk -F . '{print $1 "." $2 "." $4}'`; echo $newfile;  mv $file $newfile; done;