How can I force only relative paths in "find" output?

Question

I am attempting to create a script that can compress files with a certain extension in a number of directories into a single tar-ball. Currently what I have in the script file is:

find "$rootDir" -name '*doc' -exec tar rvf docs.tar {} \;

Where $rootDir is the base path to search.

This is fine except the paths are absolute in the tar file. I would prefer the paths to be relative to $rootDir. How would I go about doing this?

Example of current tar -tf docs.tar where $rootDir is /home/username/test output:

home/username/test/subdir/test.doc
home/username/test/second.doc

What I desire the output to be:

./subdir/test.doc
./second.doc

Answer 1

You can use the %P format in the -printf directive:

find ${rootDir} -name '*.doc' -printf "%P\n"

will display in your example:

subdir/test.doc
second.doc

You may then use this find list in a for expression, in order to run our exec command, as in:

for f in $( find ${rootDir} -name '*.doc' -printf "%P\n" );
do
    tar rvf docs.tar ${f}
done

Answer 2

If you run find from the desired root directory and don't specify an absolute starting point in find's options, it will output relative paths to the tar command invocations it constructs. Like so:

cd $rootDir
find . -name '*doc' -exec tar rvf docs.tar {} \;

If you do not want to change the current working directory permanently and are using bash or similar as your shell you could do

pushd $rootDir
find . -name '*doc' -exec tar rvf docs.tar {} \;
popd

instead.

Note that pushd/popd are not present in all shells, so check the man page as appropriate. They are present in bash but not in the base sh implementation so while explicitly using /bin/bash you can rely on them you can't if a script asks for /bin/sh instead (as this may map to a smaller shell that doesn't have bash's enhancements)