[X-Unix] Re: X-Unix Digest, Vol 18, Issue 2

[Robert Frank]

On 24/02/2006, at 6:35 , x-unix- 
request at listserver.themacintoshguy.com wrote:
> Hi,
> This is rather long, sorry.
>
> Rather than use a 'third-party' application to do my backups, I have
> written a bash script to backup my important files to another
> computer on my home lan.  Why?  Just because I can.
>
> It's working well, with the exception of a couple of things I would
> like some input on.
>
> First, I'm not satisfied with how I'm verifying that the backup
> volume on the remote server is mounted or not.  Can anyone help make
> that section 'bullet-proof'?
>
> Second, [...]
>
> Here is my script...
> *****
> #!/bin/bash
>
> ## NOTE: ADD 'n' TO THE cmd OPTIONS WHEN TESTING
>
> dc=`date +%m%d%y`
> file='/Users/Charles/Documents/backup.log.'$dc'.txt'
> cmd='rsync -uvrtp --delete-after'
> src=/Users/Charles
> dest=/Users/charles/mnt
>
> # Is the server on?
> ping -o -t 5 moe > /dev/null 2>&1
> if [ "$?" -ne 0 ] ; then
> 	# Assume server is not on, display alert and quit
> 	echo "Cannot ping server, exiting" >> $file
> 	mail -s "Weekly Backup results" charles < $file
>      	exit
> else
> 	# The server is on, is the backup volume mounted?
> 	if [ `ls /Users/charles/mnt/FreeBSD > /dev/null 2>&1` ] ; then
> 		#Volume is mounted, continue
>            ...
> 	else
> 		# Volume is not mounted, mount it and continue
> 		mount -t nfs moe:/backup /Users/charles/mnt > /dev/null 2>&1
as proposed, save the return code here

> 		if [ "$?" -eq 0 ] ; then
> 			# Mounted OK
> 			echo `date` > $file
> 			echo >> $file
> 			echo "Mounted volume successfully, continuing." >> $file
> 			echo >> $file
> 		else	
> 			# Mount failed
> 			if [ "$?" ! -eq 0 ] ; then
use '-ne' instead of '! -eq'
'!' tries to negate the following *expression* (c.f. man test) and '- 
eq 0' isn't an expression, so thigs will go wrong here!
If you insist on using '!' then it's '! "$?" -eq 0'.


> 				echo `date` > $file
> 				echo >> $file
> 				echo "Mount returned" "$?" ", exiting." >> $file
use the saved return value here

> 				mail -s "Weekly Backup results" charles < $file					
> 				exit
> 			fi
> 		fi
> 	fi
> fi

Robert

Departement Informatik   FGB   tel   +41 (0)61 267 14 66
Universität Basel                          fax. +41 (0)61 267 14 61
Robert Frank
Klingelbergstrasse 50                 Robert.Frank at unibas.ch
CH-4056 Basel
Switzerland                                   http:// 
www.informatik.unibas.ch/personen/frank_r.html