documenting shell scripts' parameters
LinuxUnixShellLinux Problem Overview
Is there a convention for documenting shell scripts' parameters?
For example:
#!/usr/bin/env bash
# <description>
#
# Usage:
# $ ./myScript param1 [param2]
# * param1: <description>
# * param2: <description>
A few things I don't like about this particular template:
- the script's file name (
myScript
) appears within the file itself - parameter description seems weird
- the leading space before
$
is visually useful, but can lead to confusion in languages with block comments, causing some validation tools to complain about mixed/inconsisent indentation (e.g. spaces in this block, tabs for code - provided one prefers tabs, of course)
Are there any guidelines on this?
Linux Solutions
Solution 1 - Linux
Traditionally you document your arguments in the usage() function:
#!/bin/bash
programname=$0
function usage {
echo "usage: $programname [-abch] [-f infile] [-o outfile]"
echo " -a turn on feature a"
echo " -b turn on feature b"
echo " -c turn on feature c"
echo " -h display help"
echo " -f infile specify input file infile"
echo " -o outfile specify output file outfile"
exit 1
}
usage
Solution 2 - Linux
I would recomment using a heredoc:
usage () {
cat <<HELP_USAGE
$0 [-a] -f <file>
-a All the instances.
-f File to write all the log lines
HELP_USAGE
}
instead of:
echo "$0 [-a] -f <file>"
echo
echo "-a All the instances."
echo "-f File to write all the log lines."
I think it is way cleaner than all these echo lines.
Solution 3 - Linux
I usually wrap my usage in function so I can call it from a -h param etc.
#!/bin/bash
usage() {
cat <<EOM
Usage:
$(basename $0) Explain options here
EOM
exit 0
}
[ -z $1 ] && { usage; }
Solution 4 - Linux
The Vim bash IDE that does this:
#!/bin/bash
#===============================================================================
#
# FILE: test.sh
#
# USAGE: ./test.sh
#
# DESCRIPTION:
#
# OPTIONS: ---
# REQUIREMENTS: ---
# BUGS: ---
# NOTES: ---
# AUTHOR: Joe Brockmeier, [email protected]
# COMPANY: Dissociated Press
# VERSION: 1.0
# CREATED: 05/25/2007 10:31:01 PM MDT
# REVISION: ---
#===============================================================================
Solution 5 - Linux
I would recommend making your script automatically print usage (if it shouldn't be run without arguments):
#!/usr/bin/env bash
if [ $# == 0 ]; then
echo "Usage: $0 param1 [param2]"
echo "* param1: <description>"
echo "* param2: <description>"
fi
Solution 6 - Linux
I would rather write:
Usage: `basename $0` [option1]|[option2] param1
Options:
- option1: .....
- option2: .....
Parameters:
- param1: .....
Try to look at the way help is formatted for standard UNIX utilities (ls --help, for instance)