26 lines
1.2 KiB
Markdown
26 lines
1.2 KiB
Markdown
# arg - A simple command line argument parser
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This is a simple tool with a simple job: figure out the value of a single
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command line argument. Tools like `getopt` and `getopts` are much too
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complicated. It's much nicer to be able to write shell scripts like this:
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```
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#!/bin/sh
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dir=`arg --dir "$@" || arg -d "$@" || echo "$HOME/Downloads"`
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if arg --verbose "$@" || arg -v "$@"; then
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echo "Downloading to $dir"
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fi
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cd $path && curl -O example.com/file.zip
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```
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## Usage
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The following forms are accepted: `arg -f ...`, `arg -flag ...`, or `arg --flag
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...`. If `arg` finds the first given flag among the rest of the command line
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arguments, it will print the flag's value (if any) and exit successfully,
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otherwise, it will fail (exit status 1). The value may be of the form
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`--flag=value`, `--flag value`, `-f value`, or `-f=value`. Single-letter flags
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will match when grouped with other single letter flags, but will not have a
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value, i.e. `arg -b -abc foo` will exit successfully without printing anything.
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When using `arg` in a shell script, it is best to use quotes around `$@`, as in
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`arg --foo "$@"`, so arguments with spaces will parse properly, like
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`my_script.sh --flag "one two"`.
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