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What is pythonp?

pythonp is a simple utility script that helps you using python on the command line. Basically, it's a python -c command with a handy print function p. See examples below to see how convenient it can be.
By design, it avoids adding much sugar to the goold old python -c. It introduces no magic except for a few preprocessings and handy global variables. The goal of this project is to deliver seamless experience to python users and become a part of some major python implementations in the end, without remaining as a standalone package.

Disclaimer

There are already several projects that have smilar goals with this project such as pyp, pythonpy and others. Particularly pythonpy is super popular. I think they are all amazing projects and I don't mean to assert that every aspect of pythonp is breakingly new.
But there are fundamental differences between pythonp and others. Notably, pythonp has been designed to be able to run any python programs, not just single statements. Any valid python code should be able to be run with pythonp and only (almost valid) python code should.

How to install

You can install it via pip

python -m pip install pythonp

or you can simply download this repository and copy __main__.py to one of your $PATH locations

cp pythonp/__main__.py ...../pythonp

Handy global variables defined

p

A handy print function with commandline usage in mind. It has the similar interface to the built-in print with some exceptions.

  • It specially handles a single iterable as an argument, in which case it prints as many times as the number of elements in the iterable. Giving extra positional arguments along with an iterable is not allowed.

lines

Standard input lines. You can think of it as sys.stdin except that each line of it doesn't end with a newline character. Also note that it's subscriptable and allows a one-time random access, which means you can do something like lines[3], lines[10:].

l

l is a line from the standard input. It also doesn't end with a new line character. Without -e option, l is the first line from the standard input. With -e option, it represents each line of the standard input. See the feature explanation below to learn -e option.

_lines

Lazy evaluted non-stream-like version of lines. Becuase it's a collections.abc.Sequence, you can access its lines multiple times, reverse it, do inclusion test on it, and so forth. The lines are not prepared until you actually use it to save up memory.

Features

  • The last expression is automatically printed with p function if your code dind't write anything to sys.stdout and the last expression does not evalute to None. If you don't want this feature you can put something like ;pass or ;None in the end of your code.

  • If -e option is given, your code is applied to each line l of the stanard input, not the entire lines lines or _lines. The names lines and _lines will disappear and can not be used. Note that in the current implementation, globals are shared during continued executions of the code and there could be some side effects. This is an intended behavior but can change in the future.

  • Automatic importing is supported. pythonp automatically tries to import a name for you when it encounters an unseen one.

  • Backtick(`) in code is replaced with """ so that you can have one more way to make string literals. In python 3.6 or above f prefix is also added to make the enclosed section a f-string. For example, you can do something like this.

$ echo 91/seoul/bombs | pythonp "`name='{l.split('/')[2]}'`"  # python3.6+
name='bombs'

Examples

Make commands that you want on the fly and and run them with your shell

# Remove extensions of .txt files
$ ls | pythonp -e "if l.endswith('.txt'): p('mv', l, l[:-4])" | sh

Randomly sample N lines from a large number of lines

# choose n files randomly
ls | pythonp "random.sample(_lines, 3)"
item_1443
item_6360
item_7285

Concatenate lines

$ ls | pythonp "','.join(l.strip() for l in lines if not 'bombs' in l)"
LICENSE,README.md,pythonp,setup.py

Do something for each line

# A web crawler one-liner
$ cat urls.txt | pythonp -e 'p(requests.get(l)); time.sleep(1)' > output

Split a long line and output the nth chunk

# Get the 4th column from the current processs status 
$ ps | tail -n+1 | pythonp -e "l.split()[3]"
/usr/local/bin/fish
-fish
python3
ssh

# Only using only pythonp
$ ps | pythonp "lines[1:]" | pythonp -e "l.split()[3]"

Others

# Use it to solve some weird quiz
$ pythonp "now=datetime.datetime.now();(now.year+now.day)%10"

# Make at most 5 random names
$ pythonp "'\n'*(5-1)" | pythonp -e "''.join(random.sample(string.ascii_letters, 7))" | xargs touch

Misc

  • If you want a shorter name for pythonp you can do something like this.
mv $(which pythonp) $(dirname $(which pythonp))/py  # rename pythonp to py