resolve-name-clash

Say you want to copy file a.txt into directory /path/to/destination/ but if /path/to/destination/a.txt exists, you don't want to overwrite it but instead copy the file to /path/to/destination/a_1.txt. This is a simple utility that does exactly one thing: given a source filename and a destination directory, it figures out a form of the source file's name in the destination directory that doesn't clash with any existing file.

The algorithm it uses to find a unique filename is as follows. Given a path to a source file and a path to a destination directory:

• Set src_filename to the filename (last path segment) of the path to the source file
• If path/to/dest/src_filename does not exist, return it
• If path/to/dest/src_filename exists:
  • Set src_file_basename to src_filename with all the extensions removed and src_file_extensions to all the extensions of src_filename
  • Successively try path/to/dest/src_file_basename + "_1" + src_file_extensions, path/to/dest/src_file_basename + "_2" + src_file_extensions, and so on until one is found that doesn't exist. Return that one.

You can use it on the command line:

$ resolve-name-clash ~/src/a.txt ~/dest/
/Users/spather/dest/a_1.txt

It's particularly useful used in a subshell with a copy or move command:

cp ~/src/a.txt $(resolve-name-clash ~/src/a.txt ~/dest)

Or you can us it in a python program:

from resolve_name_clash import resolve_name_clash

src = Path("/path/to/src/a.txt")
dest = Path("/path/to/dest")
unique_path = resolve_name_clash(src, dest)
# unique_path will be a Path object to something like /path/to/dest/a_1.txt