https://github.com/bbkane/dotfiles/blob/master/bin_common/bin_common/format_shell_cmd.py

format_shell_cmd.py

#!/usr/bin/env python3

import argparse
import sys
import typing as t

__author__ = "Benjamin Kane"
__version__ = "0.1.0"
__doc__ = f"""
Pretty-print simple Bash command from one line of stdin
Examples:
    echo 'echo "hi there" | awk "{{print $1}}"' | {sys.argv[0]}
Help:
Please see Benjamin Kane for help.
"""


def parse_args(*args, **kwargs):
    parser = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )
    return parser.parse_args(*args, **kwargs)


# need to tokenize into words, strings, pipes, options
# strings are surrounded by quotes - and can have nested quotes
# pipes are |
# options start with -
# Test with: python3 -m doctest  format_shell.py


class Kind:
    UNSET = "UNSET"
    PIPE = "PIPE"
    OPTION = "OPTION"
    SINGLE_QUOTE_STRING = "SINGLE_QUOTE_STRING"
    DOUBLE_QUOTE_STRING = "DOUBLE_QUOTE_STRING"
    CMD = "CMD"


class Token(t.NamedTuple):
    text: str
    kind: Kind


def tokenize(expr):
    """Return a list of tokens

    >>> list(tokenize(''))
    []
    >>> list(tokenize(' '))
    []
    >>> list(tokenize('|'))
    [Token(text='|', kind='PIPE')]
    >>> list(tokenize(' | '))
    [Token(text='|', kind='PIPE')]
    >>> list(tokenize(' | -'))
    [Token(text='|', kind='PIPE'), Token(text='-', kind='OPTION')]
    >>> list(tokenize(' | -bob'))
    [Token(text='|', kind='PIPE'), Token(text='-bob', kind='OPTION')]
    >>> list(tokenize(' | -bob "dillon"'))
    [Token(text='|', kind='PIPE'), Token(text='-bob', kind='OPTION'), Token(text='"dillon"', kind='DOUBLE_QUOTE_STRING')]
    >>> list(tokenize('echo | openssl s_client -connect www.example.com:443'))
    [Token(text='echo', kind='CMD'), Token(text='|', kind='PIPE'), Token(text='openssl', kind='CMD'), Token(text='s_client', kind='CMD'), Token(text='-connect', kind='OPTION'), Token(text='www.example.com:443', kind='CMD')]
    >>> list(tokenize('"bob'))
    Traceback (most recent call last):
    ...
    ValueError: Double quote at column 0 unmatched
    >>> list(tokenize('"'))
    Traceback (most recent call last):
    ...
    ValueError: Double quote at column 0 unmatched
    >>> list(tokenize('" "'))
    [Token(text='" "', kind='DOUBLE_QUOTE_STRING')]
    >>> list(tokenize('echo "hi there" | awk "{print $1}"'))
    [Token(text='echo', kind='CMD'), Token(text='"hi there"', kind='DOUBLE_QUOTE_STRING'), Token(text='|', kind='PIPE'), Token(text='awk', kind='CMD'), Token(text='"{print $1}"', kind='DOUBLE_QUOTE_STRING')]
    """

    start = 0
    end = 0
    kind = Kind.UNSET
    len_expr = len(expr)  # cache constant value
    while True:
        # eat whitespace
        while end < len_expr and expr[end].isspace():
            start += 1
            end += 1
        if end == len_expr:
            return

        if expr[end] == "|":
            end += 1
            yield Token(expr[start:end], Kind.PIPE)
            start = end
        elif expr[end] == "-":
            while end < len_expr and not expr[end].isspace():
                end += 1
            yield Token(expr[start:end], Kind.OPTION)
            start = end
        elif expr[end] == '"':
            while True:
                end += 1
                if end == len_expr:
                    raise ValueError(
                        f"Double quote at column {start} unmatched"
                    )
                if expr[end] == '"':
                    break
            end += 1
            yield Token(expr[start:end], Kind.DOUBLE_QUOTE_STRING)
            start = end
        elif expr[end] == "'":
            while True:
                end += 1
                if end == len_expr:
                    raise ValueError(
                        f"Single quote at column {start} unmatched"
                    )
                if expr[end] == "'":
                    break
            end += 1
            yield Token(expr[start:end], Kind.SINGLE_QUOTE_STRING)
            start = end
        else:  # not space, not anything else, must be cmd
            while end < len_expr and not expr[end].isspace():
                end += 1
            yield Token(expr[start:end], Kind.CMD)
            start = end


def print_cmd(tokens: t.Iterable[Token]):
    for token in tokens:
        if token.kind == Kind.PIPE:
            print(f"|\n  ", end="")
        elif token.kind == Kind.OPTION:
            print(f"\\\n    {token.text} ", end="")
        elif token.kind in (
            Kind.CMD,
            Kind.DOUBLE_QUOTE_STRING,
            Kind.SINGLE_QUOTE_STRING,
        ):
            print(f"{token.text} ", end="")
        else:
            raise ValueError(f"Unknown token kind: {token!r}")
    print()


def main():
    # get --help
    parse_args()
    command = sys.stdin.readline()
    print_cmd(tokenize(command))


if __name__ == "__main__":
    main()