website/content/blog/bashpartialargparse.md

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2020-09-08 01:47:59 +00:00
---
title: "Partial Argument Parse and Passing in Bash"
date: 2020-09-07T21:33:26-04:00
draft: false
tags: []
---
Let's say we want to augment an existing terminal command (like for example `wget`). We then want to be able to add or edit command line options. The rest of this post provides an example that hopefully you can use in your bash script.
```bash
#!/bin/bash
# Custom help function
show_help() {
echo "Usage: custom_command [arguments]"
echo " --name <name>"
echo " --flag_example"
echo " <additional arguments to be passed along>"
exit 0
}
# Defaults for our custom flags or parameters.
name=""
flag_example=0
# Loop through and take out our custom parameters
# from the parameter list.
i=0
numargs=$#
while test $i -lt "$numargs"
do
case "$1" in
"--help")
show_help
;;
"--name")
shift
name=$1
;;
"--flag_example")
flag_example=1
;;
*)
set -- "$@" "$1"
;;
esac
shift
i=$((i+1))
done
# Do something here using our custom parameters
# Pass our non-custom parameters to the application
wget "$@"
```