bashrc/src/python/add_to_a_path.py at __main__ · jalanb/bashrc · GitHub

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"""Script to display a collection of paths after inserting one new path

Usage:
    add_to_a_path.py [-U] PATHS PATH
    add_to_a_path.py [-U] (-s | -i INDEX ) PATHS PATH

Options:
    -h, --help               Show this help and exit
    -v, --version            Show version number and exit
    -s, --start              Add the path at start of list of paths
    -i INDEX, --index=INDEX  The index at which the path will be inserted


Examples of use:
    $ export PATH=/bin:/usr/bin

    $ add_to_a_path.py PATH /usr/local/bin
    PATH=/bin:/usr/bin:/usr/local/bin

    $ add_to_a_path.py PATH /usr/local/bin --start
    PATH=/usr/local/bin:/bin:/usr/bin
"""


import os
import sys
import argparse
from bdb import BdbQuit


__version__ = "0.1.0"


class ScriptError(NotImplementedError):
    pass


def version():
    print(__version__)
    raise SystemExit


def parse_args():
    """Parse out command line arguments"""
    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
    parser.add_argument("symbol", help="The bash symbol to be changed")
    parser.add_argument("path", help="The path to be added")
    parser.add_argument(
        "-s",
        "--start",
        action="store_true",
        help="Add the path at start of list of paths",
    )
    parser.add_argument(
        "-i", "--index", type=int, help="The index at which the path will be inserted"
    )
    parser.add_argument("-v", "--version", action="store_true", help="Show version")
    args = parser.parse_args()
    if args.version:
        version()
    if not args.index:
        if args.start:
            args.index = 0
        else:
            args.index = False
    return args


def _add_symbol_to_paths(paths, symbol, i):
    if i is False:
        i = len(paths)
    result = paths[:]
    if not symbol:
        return result
    if symbol not in result:
        result.insert(i, symbol)
        return result
    j = result.index(symbol)
    if i != j:
        del result[j]
        result.insert(i, symbol)
    return result


def get_arg_path(args):
    path = args.path
    if not path:
        return ""
    user_path = os.path.expanduser(path)
    real_path = os.path.realpath(user_path)
    if not os.path.isdir(real_path):
        return ""
    return real_path


def split_paths(string):
    if not string:
        return []
    return [p for p in string.split(os.path.pathsep) if p]


def get_paths(args):
    symbol = args.symbol
    paths_string = ""
    if symbol in os.environ:
        paths_string = os.environ[symbol]
    elif os.path.pathsep in symbol:
        paths_string = symbol
    return split_paths(paths_string)


def script(args):
    arg_path = get_arg_path(args)
    paths = get_paths(args)
    if not arg_path:
        if not paths:
            return False
    elif os.path.isdir(arg_path):
        if arg_path in paths:
            paths.remove(arg_path)
        paths = _add_symbol_to_paths(paths, arg_path, args.index)
    else:
        return False
    print("=".join((args.symbol, os.path.pathsep.join(paths))))
    return True


def main():
    """Run the script"""
    try:
        args = parse_args()
        return os.EX_OK if script(args) else not os.EX_OK
    except (SystemExit, BdbQuit):
        pass
    return os.EX_OK


if __name__ == "__main__":
    sys.exit(main())