Renaming files with its path name

Many GNU tools such as cp, mv and tar support creating backup files when the target exists. That is, when copying foo to bar, if there is already a file called bar, the existing bar will be renamed, and after the copy bar will contain the contents of foo. By default, bar is renamed to bar~, but the behavior can be modified:

                                # If a file foo exists in the target, then…
cp -r --backup source target    #   rename foo → foo~
cp -r --backup=t source target  #   rename foo → foo.~1~ (or foo.~2~, etc)

There are other variants, such as creating numbered backups only when one already exists. See the coreutils manual for more details.

This command will rename all files to the md5sum of their content. That means files with the same content will get the same name.

for f in *; do mv $f $(md5sum $f | cut -d " " -f 1); done

You can replace md5sum with sha1sum in the command.

For this demonstration I added -v to mv so we can see what is being renamed.

$ echo 1 > a
$ echo 2 > b
$ echo 1 > c
$ ls -1
a
b
c
$ for f in *; do mv -v $f $(md5sum $f | cut -d " " -f 1); done
`a' -> `b026324c6904b2a9cb4b88d6d61c81d1'
`b' -> `26ab0db90d72e28ad0ba1e22ee510510'
`c' -> `b026324c6904b2a9cb4b88d6d61c81d1'
$ ls -1
26ab0db90d72e28ad0ba1e22ee510510
b026324c6904b2a9cb4b88d6d61c81d1

You can also safely run this command in a directory where some files have unified filename while other have not.

$ echo 1 > d
$ echo 2 > e
$ ls -1
26ab0db90d72e28ad0ba1e22ee510510
b026324c6904b2a9cb4b88d6d61c81d1
d
e
$ for f in *; do mv -v $f $(md5sum $f | cut -d " " -f 1); done
mv: `26ab0db90d72e28ad0ba1e22ee510510' and `26ab0db90d72e28ad0ba1e22ee510510' are the same file
mv: `b026324c6904b2a9cb4b88d6d61c81d1' and `b026324c6904b2a9cb4b88d6d61c81d1' are the same file
`d' -> `b026324c6904b2a9cb4b88d6d61c81d1'
`e' -> `26ab0db90d72e28ad0ba1e22ee510510'
$ ls -1
26ab0db90d72e28ad0ba1e22ee510510
b026324c6904b2a9cb4b88d6d61c81d1

Note that it will still calculate the hash of the files that are already hashed. So if the files are huge you might want to prevent the rehashing.