I think the problem is this: The command:
[ -n A_String_of_Some_Sort ] is not a valid command.
I am an amateur, so not too slick, but I would do this:
a=`mount | grep etc...`
[ -n "$a" ] && {
PREMOUNTED=yes
echo Already mounted
}
[ -z "$a" ] && {
mount the thing
other commands here
}
This has the advantage of simplicity, always a important concern with me.
Joel
On Wed, Jan 23, 2002 at 01:55:48PM -0600, JW wrote:
> Hello,
>
> I'm trying to write a bash script for a back up job. Unfortunately I'm not getting
>anywhere.
>
>
> >I need to mount a file system only if the filesystem is
> >_not_ already mounted.
> >
> >I'm thinking of it like this:
>
> Ok, I've been reading documentation and wrote a test script. I've so far managed to
>make it like this:
>
> #!/bin/bash
>
>
> if [ -n `mount |grep "/mnt/root/cschomeserver/e"` ] #if it's already mounted don't
>mount it
> then PREMOUNTED='YES' && echo "is mounted" #If it's already mounted set a var
> else echo "mount /mnt/root/cschomeserver/e is not mounted" #if it's not mounted,
>mount it.
> fi
> echo $PREMOUNTED
>
>
> Unfortunately it seems that -n is exactly the opposite of what I need because the
>output is backwards. Additionally, it was working backwards but without error a
>minute ago and now it's giving that "too many arguments" thing - I'm not sure what's
>changed, I tried undoing my (very small) edits to the file and it's still erroring
>even after the un-do so I'm not sure what happened.
>
> When it really is mounted I get the following output from that script:
>
> fluorite:~ # ./test.sh
> ./test.sh: [: too many arguments
> mount /mnt/root/cschomeserver/e is not mounted
>
> Which is backwards - it is mounted. As you can see PREMOUNTED doesn't get set either
>- again, that's backwards.
>
> Then when it really isn't mounted the script _does_ set the var:
>
> fluorite:~ # umount /mnt/root/cschomeserver/e/
> fluorite:~ # ./test.sh
> YES
>
> So, can someone tell me what the opposite of -n is? According to the man page it's
>-z but that's acting the same as -n (weird) I can't figure it out. I've tried -n, -z
>and a host of other options I see in the man page and none of it's working and it's
>backwards both ways.
>
> Also can anyone explain the "too many arguments" part - are you not allowed to run a
>command inside [] for output?
>
> I'm also testing it with the interactive shell, such as the following variation:
>
> fluorite:~ # if test -n $( `mount |grep "/mnt/root/cschomeserver/e"` ) ; then
>PREMOUNTED="YES" && echo $PREMOUNTED ; else echo "no" ; fi
> YES
>
> Unfortunately this (and test -z) is always returning "YES" so something's still
>quite wrong.
>
> Obviously I do not understand how to properly get a yes/no value out of the string
>returned from a nested command. If someone could explain even that much I'd
>appreciate it.
>
> TIA
>
>
> ----------------------------------------------------
> Jonathan Wilson
> System Administrator
>
> Cedar Creek Software http://www.cedarcreeksoftware.com
> Central Texas IT http://www.centraltexasit.com
>
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