getopts question in bash script.

lleb · 07-13-2012, 05:44 PM

I am using getopts in a script as it can perform either FTP or RSYNC backup. when running the FTP portion it will create a tarball and as long as it is not run in -n (no kill) it will also verify and encrypt the tarball before FTP across the LAN.

I want to set the script so that if there is no option provided it does not run, but will echo a warning that -f, -r, -n, -o, -s must be called with the script.

Code:

### This file MUST be called with one of the following options.
### -n will start the script in test mode not terminating any interfaces.
### -r will start the rsync vs of the script
### -f will start the ftp vs of the sctipt
### -x will start the script in debug mode bash -xvv
### -s will run the setup portion of the script and must be run first.
### -o will print out the options

### Options
###################################

while getopts ":nrfxso" opt
do
        case $opt in
                n )     NO_KILL=true
                        ;;
		r )	DO_FTP=false
			DO_RSYNC=true
			DO_TAR=false
			;;
		f )	DO_FTP=true
			DO_RSYNC=false
			DO_TAR=true
			;;
		x )	set -xvv
			;;
		s )	DO_SETUP=true
			;;
		o )	DO_USE=true
			;;
        esac
done

shift $(( $OPTIND -1 ))

USAGE()
{
cat <<-usage

This is a test to evaluate this function.  To run this script you must first run it
with the -s option.  During the setup you will be able to choose FTP or RSYNC for backups.

You may run the setup portion more then one time if you wish to use both FTP & RSYNC.

Once the script is setup you must call with either -n, -r, -f, or any combination.
	ex: BACKUP -f -r
		this will run the FTP portion of the script first, then RSYNC after the 
		FTP is complete.  It will terminate all Rx30 screens and interfaces then
		restart them after RSYNC has completed.  It will also remove any tarballs
		left in the /tmp directory on the server.
	ex: BACKUP -f -n
		this will run the FTP portion of the script in TEST mode not terminating
		any rx30 screen or interface.  It will also not encrypt the tarball.
	ex: BACKUP -f -r -x
		Now you will run just like the first example, but it will be run in full 
		debug mode. $ bash -xvv BACKUP -f -r
usage
}

Not sure i explained that correctly. hope i did.

unSpawn · 07-13-2012, 06:09 PM

Quote:

Originally Posted by lleb

I want to set the script so that if there is no option provided it does not run, but will echo a warning that -f, -r, -n, -o, -s must be called with the script.

I often include a "help" function which basically echoes the options and exits 1. This avoids having to echo help-like text throughout a script.
- Your case statement should have a "*|h)" option which points to help and safeguards against supplying the wrong set of options.
- Before you parse getopts check if $# is empty or does not have the required minimum amount of elements and point to help.

I'm sure any of the

Code:

function howto() { echo "Bash scripting guides:
http://www.tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html 
http://www.tldp.org/LDP/Bash-Beginners-Guide/html/index.html 
http://www.gnu.org/software/bash/manual/html_node/index.html
http://www.grymoire.com/Unix/Sh.html
http://www.tldp.org/LDP/abs/html/ 
http://mywiki.wooledge.org/BashFAQ
http://mywiki.wooledge.org/BashPitfalls"; }

would show a better method but that's what I use.

lleb · 07-16-2012, 07:55 AM

thank you much. ill read over those links today while at work.

lleb · 07-16-2012, 08:06 PM

Quote:

- Your case statement should have a "*|h)" option which points to help and safeguards against supplying the wrong set of options.

where? is that part of the start of the getopts or is that in lower down???

Code:

while getopts "*h|:n" opt

or

Code:

case *h| $opt in

or lower still...

Code:

	case $opt in
		*h )	help=true
			;;

also does the *h force the script to mandate some type of - argument to run?

unSpawn · 07-20-2012, 05:37 PM

Quote:

Originally Posted by lleb

or lower still...

Code:

	case $opt in
		*h )	help=true
			;;

Yes, that's the place, after all it's just a case statement option.

Quote:

Originally Posted by lleb

does the *h force the script to mandate some type of - argument to run?

Getopts itself catches any unknown options with an error but if you want to check for anything yourself you should put it before the script does anything significant. In the example below you only expect one argument, the arg starts with a dash and shoudln't exist of just a dash:

Code:

#!/bin/bash
_help() { echo "programname: [options]" >/dev/stderr; exit 1; }
[ $# -ne 1 -o "${1:0:1}" -ne "-" -o ${#1} -ne 2 ] && _help
while getopts "nrfxsoh" OPTION; do
        case "${OPTION}" in
                # other options here before "h|*"
                h|*) _help;;