Docs for appending the parent directory name to the name of files it contains

appending-parent-dir-name-to-filenames.md

Create some test files. I've assumed your filenames have a single "." character:

mkdir foo
touch foo/one.txt foo/two.txt foo/three.txt

If you list the files (ll foo) you'll get something like:

total 0
-rw-r--r--  1 molomby  staff     0B 21 Mar 21:49 one.txt
-rw-r--r--  1 molomby  staff     0B 21 Mar 21:49 three.txt
-rw-r--r--  1 molomby  staff     0B 21 Mar 21:49 two.txt

Now we're going to loop over the files and use some string manipulation to rename them.

for file in foo/*;
do 
  mv "${file}" "${file%%.*}-${file%%/*}.${file##*.}"
done

Lets unpack that a little.

• The first line itterates over the files matching the foo/* glob. The file var will have a values like foo/one.txt, etc.
• We're running a move command from the current file (${file}) to a new filename built out of parts:
  • ${file%%.*} -> the file path, with everything after the "." removed (eg. foo/one)
  • - -> a litteral "-" charactor
  • ${file%%/*} -> the file path, with everything after the "/" removed (eg. foo)
  • . -> a litteral "." charactor
  • ${file##*.} -> the file path, with everything before the "." removed (eg. txt)

The commands are wrapped in quotes in case there are spaces in the filenames. So we end up running these commands:

mv "foo/one.txt" "foo/one-foo.txt"
mv "foo/three.txt" "foo/three-foo.txt"
mv "foo/two.txt" "foo/two-foo.txt"

If you listing the files again (ll foo) you'll get:

total 0
-rw-r--r--  1 molomby  staff     0B 21 Mar 21:49 one-foo.txt
-rw-r--r--  1 molomby  staff     0B 21 Mar 21:49 three-foo.txt
-rw-r--r--  1 molomby  staff     0B 21 Mar 21:49 two-foo.txt

Why does

for folder in test_dir/C*
do 
for file in ${folder}/*;
do 
  mv "${file}" "${file%%.*}-${folder##*/}.${file##*.}"
done
done

work

but not

for folder in test_dir/C*
do 
for file in ${folder}/*;
do 
  mv "${file}" "$${folder##*/}-{file%%.*}.${file##*.}"
done
done

It's to do with the string but I don't understand how to stop the manipulation going up so far?

Neverrrrr miiiind! I worked out an ugly solution!