Argparse Bash Save

Use python's argparse module in shell scripts

Project README

=============== argparse.bash

Use Python's argparse module in shell scripts

.. image:: https://github.com/nhoffman/argparse-bash/actions/workflows/test.yml/badge.svg :target: https://github.com/nhoffman/argparse-bash/actions/workflows/test.yml

The function argparse parses its arguments using argparse.ArgumentParser. The command line options are defined in the function's stdin. argparse.bash should be in the same directory as a script that uses it.

Python 2.7 or 3.5+ is required. See https://docs.python.org/2.7/library/argparse.html for a description of the python module. Note that some of the Python module's features won't work as expected (or at all) in this simplistic implementation.

Installation

Get argparse.bash::

wget https://raw.githubusercontent.com/nhoffman/argparse-bash/master/argparse.bash chmod +x argparse.bash

Then move the file into the same directory as any scripts that will use it.

Alternatively, you can paste the body of the argparse() function into your script (in which case you would of course omit the line sourcing argparse.bash in the examples below).

Usage

Here's an example, example.sh::

#!/usr/bin/env bash

ARGPARSE_DESCRIPTION="Sample script description" # this is optional source $(dirname $0)/argparse.bash || exit 1 argparse "[email protected]" <<EOF || exit 1 parser.add_argument('infile') parser.add_argument('outfile') parser.add_argument('-a', '--the-answer', default=42, type=int, help='Pick a number [default %(default)s]') parser.add_argument('-d', '--do-the-thing', action='store_true', default=False, help='store a boolean [default %(default)s]') parser.add_argument('-m', '--multiple', nargs='+', help='multiple values allowed') EOF

echo required infile: "$INFILE" echo required outfile: "$OUTFILE" echo the answer: "$THE_ANSWER" echo -n do the thing? if [[ $DO_THE_THING ]]; then echo " yes, do it" else echo " no, do not do it" fi echo -n "arg with multiple values: " for a in "${MULTIPLE[@]}"; do echo -n "[$a] " done echo

Example output of this script::

$ ./example.sh infile.txt "name with spaces.txt" required infile: infile.txt required outfile: name with spaces.txt the answer: 42 do the thing? no, do not do it arg with multiple values: []

Note that hyphens in the long option names are changed to underscores, and variables are all-caps (to be more bash-y).

Help text looks like this::

$ ./example.sh -h usage: example.sh [-h] [-a THE_ANSWER] [-d] [-m MULTIPLE [MULTIPLE ...]] infile outfile

Sample script description

positional arguments: infile outfile

optional arguments: -h, --help show this help message and exit -a THE_ANSWER, --the-answer THE_ANSWER Pick a number [default 42] -d, --do-the-thing store a boolean [default False] -m MULTIPLE [MULTIPLE ...], --multiple MULTIPLE [MULTIPLE ...] multiple values allowed

Error messages::

$ ./example.sh foo usage: example.sh [-h] [-a THE_ANSWER] [-d] [-m MULTIPLE [MULTIPLE ...]] infile outfile example.sh: error: too few arguments $ ./example.sh foo bar -n baz usage: example.sh [-h] [-a THE_ANSWER] [-d] [-m MULTIPLE [MULTIPLE ...]] infile outfile example.sh: error: unrecognized arguments: -n baz

Executing argparse.bash (as opposed to sourcing it) prints a script template to stdout::

$ ./argparse.bash #!/usr/bin/env bash

source $(dirname $0)/argparse.bash || exit 1 argparse "[email protected]" <<EOF || exit 1 parser.add_argument('infile') parser.add_argument('-o', '--outfile')

EOF

echo "INFILE: ${INFILE}" echo "OUTFILE: ${OUTFILE}"

A few notes:

  • action=store_true or store_false provides a value of "yes" for True, "" for False
  • args='+' or args='*' provides an array of values.

License

MIT License (see LICENSE.txt)

Copyright (c) 2017 - 2022 Noah Hoffman

Open Source Agenda is not affiliated with "Argparse Bash" Project. README Source: nhoffman/argparse-bash
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