all - fail when cwd does not exist

[uglygus]

Tested with renumber and recombine. It will fail with others too.

File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/inspect.py", line 721, in getabsfile
    return os.path.normcase(os.path.abspath(_filename))
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.8/lib/python3.8/posixpath.py", line 379, in abspath
    cwd = os.getcwd()
FileNotFoundError: [Errno 2] No such file or directory
➜  img2vid_cear086d cwd