Using bash I need to perform a find of 0 byte files but report on their existence before deletion - bash

Question

The history of this problem is:
I have millions of files and directories on a NAS system. I found a count of 1,095,601 empty (0 byte) files. These files used to have data but were destroyed by a predecessor not using the correct toolsets to migrate data between an XSAN and this Isilon NAS.
The files were media production data, like fonts, pdfs and image files. They are no longer useful beyond the history of their existence. Before I proceed to delete them, the production user's need a record of which files used to exist, so when they browse a project folder, they can use the unaffected files but then refer to a text file in the same directory which records which files used to also be there and thus provide reason as to why certain reference files are broken.
So how do I find files across multiple directories and delete them but first output their filename to a text file which would be saved to each relevant path location?
I am thinking along the lines of:
for file in $(find . -type f -size 0); do
echo "$file" >> /PATH/TO/FOUND/FILE/PARENT/DIR/deletedFiles.txt -print0 |
xargs -0 rm ;
done

Answer 1

To delete each empty file while leaving behind a file called deletedFiles.txt which contains the names of the deleted files, try:
PATH=/bin:/usr/bin find . -empty -type f -execdir bash -c 'printf "%s\n" "$#" >>deletedFiles.txt' none {} + -delete
How it works
PATH=/bin:/usr/bin
This sets a temporary but secure path.
find .
This starts find looking in the current directory
-empty
This tells find to only look for empty files
-type f
This restricts find to looking for regular files.
-execdir bash -c 'printf "%s\n" "$#" >>deletedFiles.txt' none {} +
In each directory that contains an empty file, this adds the name of each empty file to the file deletedFiles.txt.
Notice the peculiar use of none in the command:
bash -c 'printf "%s\n" "$#" >>deletedFiles.txt' none {} +
When this command is run, bash will execute the string printf "%s\n" "$#" >>deletedFiles.txt and the arguments that follow that string are assigned to the positional parameters: $0, $1, $2, etc. When we use $#, it does not include $0. It, as is usual, expands to $1, $2, .... Thus, we add the placeholder none so that the placeholder is assigned is the $0, which we will ignore, and the complete list of file names are assigned to "$#".
-delete
This deletes each empty file.

Answer 2

Why not simply
find . -type f -size 0 -exec rm -v + |
sed -e 's%^removed .\./%%' -e 's/.$//' >deletedFiles.txt
If your find is too old to support -exec ... + you'll need to revert to -exec rm -v {} \; or refactor to
find . -type f -size 0 -print0 |
xargs -r -0 rm -v |
sed -e 's%^removed .\./%%' -e 's/.$//' >deletedFiles.txt
The brief sed script is to postprocess the output from rm -v which looks like
removed ‘./bar’
removed ‘./foo’
(with some funny quote characters around the file name) on my system. If you are fine with that output, of course, just omit the sed script from the pipeline.
If you know in advance which directories contain empty files, you can run the above snippet individually in those directories. Assuming you saved the snippet above as a script (with a proper shebang and execute permissions) named find-empty, you could simply use
for path in /path/to/first /path/to/second/directory /path/to/etc; do
cd "$path" && find-empty
done
This will only work if you have absolute paths (if not, you can run the body of the loop in a subshell by adding parentheses around it).
If you want to inspect all the directories in a tree, change the script to print to standard output instead (remove >deletedFiles.txt from the script) and try something like
find /path/to/tree -type d -exec sh -c '
t=$(mktemp -t find-emptyXXXXXXXX)
cd "$1" &&
find-empty | grep . >"$t" &&
mv "$t" deletedFiles.txt ||
rm "$t"' _ {} \;
This uses a temporary file so as to avoid updating the timestamp of directories which do not contain any empty files. The grep . is used purely for side effect; if any (non-empty) lines are printed, it will return success, whereas otherwise, it will report failure; this way, we know whether or not to move the temporary file to the target directory.

Answer 3

With prompting from #JonathanLeffler I have succeeded with the following:
#!/bin/bash
## call this script with: find . -type f -empty -exec handleEmpty.sh {} +
for file in "$#"
do
file2="$(basename "$file")"
echo "$file2" >> "$(dirname "$file")"/deletedFiles.txt
rm "$file"
done
This means I retain a trace of the removed files in a deletedFiles.txt flag file in each respective directory for the users to see when files are missing. That way, they can pursue going back to archive CD's to retrieve these deleted files, which are hopefully not 0 byte files.
Thanks to #John1024 for the suggestion of using the empty flag rather than size.