Linux – How to calculate a relative path from two absolute paths in Linux shell

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)

Tab is precisely what you need. If you hit tab twice, it will show you all possible completions:

$ cd /usr/  ## Hit tab twice here
bin/     include/ lib64/   sbin/    src/     
games/   lib/     local/   share/   var/     

You don't need to know the first letter, the second tab will show you everything.