Bdtyktl

In Ubuntu 18.10 have beeen using mmv to prepend folder names (a date) to file names within multiple folders ('-n' flag here to review results):

mmv -n './????-??-??*/*.*' './#1#2#3#4-#5#6-#7#8#9/#1#2#3#4#5#6#7#8-#10.#11'

which for example converts:

./2018-12-11/DSC05287.ARW -> ./2018-12-11/20181211-DSC05287.ARW

It also converts:

./2018-12-11/20181211-DSC05287.ARW -> ./2018-12-11/20181211-20181211-DSC05287.ARW

whilst maintaining the timestamps.

Some files have already been renamed, some have not.

How can I filter the command to exclude files matching a pattern - those which start with an 8-digit number followed by a hyphen?

Or do I need a different approach?

I'm not a fan of all-in-one renaming utilities, so here's how I would do it using only "standard (GNU) equipment", specifically bash, find and mv.

Assuming you're only interested in files that are one directory level down (so find -maxdepth 2), and specifically ignoring files that have already been previously renamed (but doing a sanity check with regex backreferences to avoid making assumptions):

find -regextype egrep -maxdepth 2 -type f ! -regex './([0-9]{4})-([0-9]{2})-([0-9]{2}).*/123-.+' | while read f; do



  if [[ $f =~ ^(./([0-9]{4}-[0-9]{2}-[0-9]{2}).*)/(.+)$ ]]; then

    # The above regex groups its matches into:

    # ${BASH_REMATCH[1]} = the dir pathname

    # ${BASH_REMATCH[2]} = the date in the dir pathname (remember to strip its dashes)

    # ${BASH_REMATCH[3]} = the file name



    mv -v "$f" "${BASH_REMATCH[1]}"/"${BASH_REMATCH[2]//-}-${BASH_REMATCH[3]}"



  fi



done

And to fix the ones that have already been incorrectly "double-dated" (again, using backreferences to avoid making unwarranted assumptions):

find -regextype egrep -maxdepth 2 -type f -regex './([0-9]{4})-([0-9]{2})-([0-9]{2}).*/123-123-.+' | while read f; do



  if [[ $f =~ ^(./.+)/([0-9]{8})-[0-9]{8}-(.+)$ ]]; then

    # The above regex groups its matches into:

    # ${BASH_REMATCH[1]} = the dir pathname

    # ${BASH_REMATCH[2]} = the first date chunk

    # ${BASH_REMATCH[3]} = the filename "tail"



    mv -v "$f" "${BASH_REMATCH[1]}/${BASH_REMATCH[2]}-${BASH_REMATCH[3]}"



  fi



done

Further Reading:

• 
  Regular-Expressions.info: in case you need help with regexes


• 
  bash(1) man page: search for the =~ operator, then read up on the special BASH_REMATCH array


• 
  findutils | Regular Expressions: details on the surprising variety of regexes supported by GNU find and locate.