Comments on: The 60 second getopts tutorial

By: Cheap Computers

Cheap Computers — Wed, 10 Feb 2010 17:01:27 +0000

Very informative article. I’ve found your blog via Yahoo and I’m really glad about the information you provide in your posts.

By: Chris F.A. Johnson

Chris F.A. Johnson — Mon, 14 Dec 2009 16:54:57 +0000

“‘/bin/*.sh’ will always have to be enclosed in single quotes, since bash will always try to expand it to a list of filenames if you don’t.”

It will not be expanded inside any quotes, single or double.

“collect $* and pass it to the function that you want to run getopts from”

No, you pass “$@” (with the quotes).

By: bun

bun — Wed, 11 Nov 2009 07:34:39 +0000

$ 1 thing ‘getopts’ doesn’t offer is a way to specify optional arg. ‘getopt’ is the solution, it’s an external tool.
$ it’s used differently, mainly it isn’t designed to be used directly as condition in loop
$ a tricky part is that to denote that a param is to be treated as opt arg, not script arg, is that for single char opt, there’s no space between the opt & the arg, for long opt, it’s the usual

By: intech_guy

intech_guy — Wed, 26 Aug 2009 06:47:59 +0000

In response to rubin427:

That makes sense from both a general programming and bash perspective. The $# and associated variables are relative to scope.

You will return all the command line parameters when examining $# from the main body, with $0 being the executed script name as called.

When checking $# from within a function it will return the function arguments (if any) with the function name (=$0).

By: pierce.jason

pierce.jason — Wed, 29 Jul 2009 07:44:08 +0000

rubin: Your conclusion is correct. What you can do, is collect $* and pass it to the function that you want to run getopts from. Otherwise getopts examines the arguements to the function that it is ran from. This can be usefull for allowing a functions syntax to mirror that of an external program.

By: passing arguments - Shell Programming and Scripting - The UNIX and Linux Forums

passing arguments - Shell Programming and Scripting - The UNIX and Linux Forums — Tue, 19 May 2009 17:06:09 +0000

[...] command -o arg1 -p -q arg2 Options start with a – and may or may not have arguments, plus they can occur in any order. Hence getopts getopts tutorial – The 60 second getopts tutorial [...]

By: hyperion

hyperion — Tue, 07 Apr 2009 18:53:35 +0000

How does the optstring look for optional flags I need to achieve this:

script.sh -(e|d) -i ‘//’ -o // -p

I have resigned to the fact that the -i flag’s value, let’s say ‘/bin/*.sh’ will always have to be enclosed in single quotes, since bash will always try to expand it to a list of filenames if you don’t.

By: Jonathan Lefflre

Jonathan Lefflre — Sat, 21 Mar 2009 18:48:47 +0000

Responding to rubin427: getopts is an odd built-in function that implicitly processes “$@”, and “$@” inside a function means the arguments to the function rather the arguments to the script as a whole. Unless you pass “$@” to the function that processes getopts, you are unlikely to be successful.

This script works (both ksh and bash – the (a) notation in the case does not work in classic Bourne shell, but the rest does):

#!bin/ksh

aflag=0
bflag=0
ffile=”"

somefunc()
{
echo “somefunc: $*”
while getopts “abf:” x
do
case $x in
(a) aflag=1;;
(b) bflag=1;;
(f) ffile=”$OPTARG”;;
(*) echo “Dunno!” 1>&2; exit 1;;
esac
done
}

somefunc “$@”

echo “aflag=$aflag”
echo “bflag=$bflag”
echo “ffile=$ffile”

By: Ken

Ken — Wed, 04 Mar 2009 21:20:21 +0000

What is $badOptionHelp set to? It doesn’t seem to be automatically set like OPTARG.

For that matter, you seem to assume that function printHelpAndExit exists.

By: Aaditya Bhatia

Aaditya Bhatia — Mon, 23 Feb 2009 09:32:04 +0000

Thanks for this concise tutorial! It helped.