imankulov / nfn

A dependency-free console script to generate filenames with sequential suffixes

nfn ("next file name")

nfn is a dependency-free console tool to generate the filename with sequential suffixes. Returns the next available filename in the directory. E.g., if your current directory has files experiment001.json and experiment002.json, the command nfn experimentNNN.json returns experiment003.json

Installation

The script works with Python3.7 and newer.

curl -s https://raw.githubusercontent.com/imankulov/nfn/main/nfn.py -o /usr/local/bin/nfn
chmod +x /usr/local/bin/nfn

Usage examples

Create new files.

$ nfn --touch experimentNNN.json
experiment001.json
$ nfn --touch experimentNNN.json
experiment002.json

Get the next of the next file without creating anything.

$ nfn experimentNNN.json
experiment003.json

Use in scripts. For example, profiling a Django management command with cProfile.

$ python -m cProfile -o $(nfn djangoNNN.prof) ./manage.py migrate

Uniqueness guarantees on concurrent calls

• The script doesn't guarantee file uniqueness on concurrent calls without the --touch flag. In other words, if you call nfn without --touch from multiple processes simultaneously, there's a chance that some of these calls return the same filenames.
• With a --touch flag, the script guarantees that all invocations from the same directory return different filenames. Notice that --touch will also create a file in the directory.