Pyp – Easily, magically, run Python at the shell

pyp

Easily run Python at the shell! Magical, but never mysterious.

Installation

Run pip install pypyp

(note the extra "yp"!)

pyp requires Python 3.6 or above.

How it works

pyp will statically analyse the input code to detect unused variables. Based on what it finds, it will proceed to transform the AST of the input code as needed. We then compile and execute the result, or if using --explain , unparse the AST back to source code.

Examples

This section will walk you through the details of using pyp , and hopefully replace your needs for many common shell utilities. For a cheatsheet / tldr, run pyp --help .

pyp can easily be used to apply Python code to each line in the input. Just use one of the magic variables x , l , s or line to refer to the current line.

# pyp like cut
ls | pyp 'x[:3]'
ps x | pyp 'line.split()[4]'

pyp can be used to easily apply Python code to the entire input as well. Use the magic variable lines for a list of rstripped lines or stdin for sys.stdin .

# pyp like wc -c
cat /usr/share/dict/words | pyp 'len(stdin.read())'

# pyp like awk
seq 1 5 | pyp 'sum(map(int, lines))'

pyp will automatically import modules you use.

# pyp like sh
echo echo echo | pyp 'subprocess.run(lines[0], shell=True); pass'

# pyp like jq
curl -s 'https://api.github.com/repos/hauntsaninja/pyp/commits?per_page=1' | pyp 'json.load(stdin)[0]["commit"]["author"]'

# pyp like egrep
cat /usr/share/dict/words | pyp 'x if re.search("(p|m)yth", x) else None'

For collections , math , itertools , pathlib.Path , pprint.pp , pyp will figure it out even if you don't use the qualified name.

# pyp like bc
pyp 'sqrt(5)'

# pyp like ${x##*.}
ls | pyp 'Path(x).suffix'

pyp can give you access to loop indices using the magic variables i , idx or index .

# pyp like line numbers
cat setup.py | pyp 'f"{idx+1: >3} {x}"'

Note so far you haven't had to call print ! By default, pyp will print the last expression in your code — except if it evaluates to None . And you can always explicitly call print yourself, in which case pyp will stay out of your way.

# pyp like grep
cat /usr/share/dict/words | pyp 'x if "python" in x else None'
cat /usr/share/dict/words | pyp 'if "python" in x: print(x); "this won't print"'

pyp will intelligently attempt to print dicts and iterables in a way that makes it easier to compose with shell tools. Again, explicit printing will stop this magic, but pyp makes the function pypprint available if you do want to explicitly opt back in.

# pyp like tail
ls | pyp 'lines[-10:]'

# pyp like sort
ls | pyp 'sorted(lines)'
ls | pyp 'print(f"Sorting {len(lines)} lines"); pypprint(sorted(lines))'

# pyp like sort | uniq
ls | pyp 'sorted(set(lines))'

pyp lets you run snippets of Python before and after processing input. Note if you run into trouble with semicolons and want a new line, you can just pass another string to pyp . You can also always pipe pyp to pyp !

# pyp like anything!
ps aux | pyp -b 'd = defaultdict(list)' 'user, pid, *_ = x.split()' 'd[user].append(pid)' -a 'del d["root"]' -a 'd'

pyp can be magical, but it doesn't have to be mysterious! Use --explain or --script to get a script equivalent to what pyp will run. This can also be a useful starting point for more complex scripts.

pyp --explain -b 'd = defaultdict(list)' 'user, pid, *_ = x.split()' 'd[user].append(pid)' -a 'del d["root"]' -a 'd'

from collections import defaultdict
from pyp import pypprint
import sys
d = defaultdict(list)
for x in sys.stdin:
    x = x.rstrip('\n')
    (user, pid, *_) = x.split()
    d[user].append(pid)
del d['root']
if d is not None:
    pypprint(d)

Related projects

Pyed Piper aka Python Power at the Prompt

pyp takes inspiration (and the command name!) from here. However, Pyed Piper appears to be unmaintained, Python 2 only, and further away from Python syntax than pyp aims to be.

Pyped

I discovered Pyped while making this project! It's actually very similar, probably similar enough that I wouldn't have written this had I known. However, Pyped doesn't do the AST introspection and manipulation that we do. This means:

• It's less magical! It relies on you to pass in flags to tell it what to do, when intention can be inferred from the input.
• It doesn't provide easy automatic printing, or smart printing of iterables and dicts.
• It hardcodes a list of imports and installs some libraries on your system. This project's automatic import will work for any library you use.
• It doesn't have anything like --explain / --script .

However,

• It has some conveniences, like regex splitting of input, that you'd have to do for yourself here.
• It supports Python 2 and early versions of Python 3.
• It's been around for much longer.

xonsh

xonsh is a shell whose language is a superset of Python; this is more ambitious and pretty different from pyp . pyp is easier to use for the one-liner piping use case, but if you need more Python in your shell, check out xonsh .

awk

If awk works for you, how did you end up here?