prs

prs is a small utility that lets you pipe things to Python and process them in a list comprehension.

If you've ever wished you could manipulate items in your shell with a Python list comprehension, prs is for you.

Installation

Just pip install prs.

Usage

prs is simple. You pipe stuff into it from the shell, it exposes whatever is piped as a list called i (without final newlines) to a script, and expects the script to return either a string or an iterable to a variable called o. That variable is then printed to stdout, so you can pipe it to sh for execution.

$ ls -1
LICENSE
prs/
README.md
setup.cfg
setup.py

$ ls -1 | prs "o = [l.lower() for l in i]"
license
prs
readme.md
setup.cfg
setup.py

Multiple lines can be separated by a semicolon.

Various libraries are already imported (but feel free to import your own):

• os
• re
• sys
• pathlib.Path

Examples

Note: The examples here won't actually run the commands, they will just display them so you can see what will actually run. To run the commands for real, just append | sh to each example.

Append .bak to all files in the current directory:

$ ls -1 | prs "o = ['mv {} {}.bak'.format(l, l) for l in i if Path(l).is_file()]"
mv LICENSE LICENSE.bak
mv README.md README.md.bak
mv setup.cfg setup.cfg.bak
mv setup.py setup.py.bak

Concatenate all entries into one:

02:28:39 $ ls -1 | prs "o = 'touch ' + ' '.join(i)"
touch LICENSE prs README.md setup.cfg setup.py

Completely ignore all input:

02:29:35 $ ls -1 | prs "o = 'hi'"
hi

Change the extension of all files in all subdirectories:

$ prs 'o = ["mv %s %s" % (l, l.with_suffix(".2py")) for l in Path(".").glob("**/*.py")]'
mv setup.py setup.2py
mv build/lib/prs/cli.py build/lib/prs/cli.2py
mv build/lib/prs/__init__.py build/lib/prs/__init__.2py
mv prs/cli.py prs/cli.2py
mv prs/__init__.py prs/__init__.2py