Bash script to swap file locations, files with same names - bash

Question

I have a bunch of .mov video in a folder on my mac:
Documents/MyMovs
├── SubFolder01
│   ├── SubSubFolder01
│   │   ├── MyFile1.mov
│   │   ├── MyPdf.pdf
│   │   └── MyTxt.txt
│   └── SubSubFolder02
│   ├── MyFile2.mov
│   ├── MyPdf.pdf
│   └── MyTxt.txt
etc.
Using HandBrake I converted all of them to .mp4 but HandBrake put them all in Movies/
Movies
├── MyFile1.mp4
├── MyFile2.mp4
etc.
What I want to do is swap the files and get the exact reverse situation where all my mp4 are stored (at the correct location) in Documents/MyMovs and all mov files are in Movies/ where I will be able to delete them eventually.
at the end I want:
Documents/MyMovs
├── SubFolder01
│   ├── SubSubFolder01
│   │   ├── MyFile1.mp4
│   │   ├── MyPdf.pdf
│   │   └── MyTxt.txt
│   └── SubSubFolder02
│   ├── MyFile2.mp4
│   ├── MyPdf.pdf
│   └── MyTxt.txt
etc.
and
Movies
├── MyFile1.mov
├── MyFile2.mov
etc.
I've designed the following bash script to help me (although I have the time to do it by hand due to the coronavirus crisis):
#!/usr/local/bin/bash
MOV_DIR=$1
MP4_DIR=$2
declare -A FILES=( )
find $MOV_DIR -maxdepth 3 -name '*.mov' -print0 |
while IFS= read -r -d '' line; do
filename=$(basename "$line")
extension="${filename##*.}"
filename="${filename%.*}"
path_to_file=$(dirname "$line")
if [[ ! -v FILES[$filename] ]]; then
FILES[$filename]="$path_to_file"
#echo $FILES[$filename] prints something!
fi
done
#for k in "${!FILES[#]}"; do echo "$k - ${FILES[$k]}"; done ## prints nothing!
find $MP4_DIR -maxdepth 3 -name '*.mp4' -print0 |
while IFS= read -r -d '' line; do
filename=$(basename "$line")
extension="${filename##*.}"
filename="${filename%.*}"
path_to_file=$(dirname "$line")
if [[ ! -z ${FILES["$filename"]} ]]; then
mv "$path_to_file/$filename.mp4" "${FILES[$filename]}"
mv "${FILES[$filename]}/filename.mov" "$path_to_file"
#I would like to remove $filename from FILES as well but I don't know how
fi
done
Let's assume all filenames are unique and distinct from each other for simplicity.
I put all my mov files in a map filename -> path_to_filename; for example MyFile1 -> Documents/MyMovs/SubFolder01/SubSubFolder01 . This is the first find block.
Secondly I find all my mp4 files and retrieve the correct location using the map.
The code does not work it seems the map is local to the first find command and does not exist after. Would anybody know why? I use bash version 5.0.16(1)-release. Thanks everybody!
PS: I you have a completely different but better solution feel free to share

Answer 1

If you have one file, then find the other
find Documents -maxdepth 4 -mindepth 3 -name '*.mov' -print0 |
while IFS= read -r -d '' mov; do
# extract the filename without extension
name=$(basename "$mov" .mov)
# find exactly the same name in Movies but with mp4
mp4="Movies/$name.mp4"
if [[ ! -f "$mp4" ]]; then
echo "ERROR: File $mp4 does not exists" >&2
exit 2
fi
# switch mp4 with mov
movdir=$(dirname "$mov")
mp4dir=$(dirname "$mp4")
echo mv -v "$mp4" "$movdir"
echo mv -v "$mov" "$mp4dir"
done
With the following directory/file recreation:
# find -type f
./Documents/MyMovs/Subfolder01/SubSubFolder01/MyFile1.mov
./Documents/MyMovs/Subfolder01/SubSubFolder02/MyFile2.mov
./Movies/MyFile1.mp4
./Movies/MyFile2.mp4
outputs:
mv -v Movies/MyFile1.mp4 Documents/MyMovs/Subfolder01/SubSubFolder01
mv -v Documents/MyMovs/Subfolder01/SubSubFolder01/MyFile1.mov Movies
mv -v Movies/MyFile2.mp4 Documents/MyMovs/Subfolder01/SubSubFolder02
mv -v Documents/MyMovs/Subfolder01/SubSubFolder02/MyFile2.mov Movies
does not exist after. Would anybody know why?
Because the right side of | is run in a subshell. Parent shell doesn't know anything about child shell environment.
$ echo | { a=1; echo a=$a; }
a=1
$ echo a=$a
a=