26 lines
1.1 KiB
Markdown
26 lines
1.1 KiB
Markdown
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# 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 "$HOME/Downloads"`
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if arg -v "$@" || arg --verbose "$@"; then
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echo "Downloading to $dir"
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fi
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cd $path && curl -O example.com/file.zip
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```
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## Usage
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`arg -f ...`, `arg -flag ...`, or `arg --flag ...`. If `arg` finds the
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given flag among the rest of the command line arguments, it will print
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the flag's value (if any) and exit successfully, otherwise, it will
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fail (exit status 1). The value may be of the form `--flag=value`,
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`--flag value`, `-f value`. Single-letter flags will match when grouped
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with other single letter flags, but will not have a value, i.e.
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`arg -b -abc foo` will exit successfully without printing anything.
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When using `arg` in a shell script, it is best to use quotes around `$@`,
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as in `arg --foo "$@"`, so arguments with spaces will parse properly,
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like `my_script.sh --flag "one two"`.
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