Question

I want to write a script that compares two directories.
However, the file names are modified in one of them.
So directory A contains files like HouseFile.txt, CouchFile.txt, ChairFile.txt
Directory B contains House.txt, Couch.txt, Chair.txt (which should be seen as ‘equivalent’ to the above)
Both may also contain new, completely different files.

Could someone point me in the right direction here? It’s been a while since I’ve done scripting.

I have tried using diff, and I know I need to use some form of regexto compare the file names, but I am not sure where to start.

Thank you!

Added for clarification:

Of course diff, however, just compares the actual file names. I would like to know how to specify that I regard files names such as, in the example, “HouseFile.txt” and “House.txt” as equivalent in this case

Answer 1

If I understand correctly, this is a possible solution to compare a to b:

mkdir a b ; touch a/HouseFile.txt a/ChairFile.txt a/CouchFile.txt a/SomeFile.txt b/House.txt b/Chair.txt b/Couch.txt b/Sofa.txt

for file in a/*(.); do [[ ! -f b/${${file##*/}:fs@File@} ]] && echo $file ; done

Outputs:
a/SomeFile.txt

What is not clear to me: Is the difference pattern strictly ‘File’ or any arbitrary string?

EDIT: The previous was for zsh. Here is one for bash:

find a -type f -maxdepth 1 | while read file; do
  check=$(echo $file | sed -r -e 's@(.*)/(.*)@\2@' -e "s@File@@") ;
  [[ ! -f b/${check} ]] && echo $file
done

Using parameter expansion instead of sed:

find a -type f -maxdepth 1 | while read file; do
  check=${file/%File.txt/.txt} #end of file name changed
  check=${check/#*\//} #delete path before the first slash
  [[ ! -f b/${check} ]] && echo $file
done