bash script help?

[Knute Johnson]

On 11/14/2011 2:09 AM, Colin Watson wrote:
> On Sun, Nov 13, 2011 at 09:40:47PM -0800, Knute Johnson wrote:
>> I've got a bash script that I run in cron.daily to backup some data
>> to a jump drive.  One of the commands in my script is to umount the
>> drive. If I write;
>>
>> if umount /dev/sdb1; then
>>      #do something
>> fi
>>
>> it always does it even if the umount is successful.
>
> The code above means "do something *only* if umount exits successfully".
> If you want to do something if umount fails, then you need:
>
>    if ! umount /dev/sdb1; then
>        # do something
>    fi
>

Isn't something other than 0 true?  umount should return false if it 
fails to mount and in my example it would #do something if it failed to 
unmount, yes?

Thanks,

-- 

Knute Johnson