[NTLUG:Discuss] Simple bash shell question

[. Daniel]

I found the culprit and a new/better way to do it.

As it turns out, doing the pipe thing forks another shell process and so 
the scope of the variables is different.  So here's what I did to overcome 
that:

----
#!/bin/sh
fcount=0
for filename in $( ls -1 *.mpg )
do
    fcount=$(expr $fcount + 1 )
    echo $fcount
done
echo $fcount
----

It now behaves as I intended.  Eventually, this will become a Nautilus 
script and I will replace "ls -1 *.mpg" with "echo 
$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS" to get a list of selected filename.  
I need to count the filenames so I can then calculate a percentage value 
for completion and pass it to zenity so I can have a progress meter dialog.

So, count first, then process, all the while echoing the progress values to 
zenity so I can see how far along it has gone.  Crazy right?


>. Daniel wrote:
>
> >This is probably so elementary that maybe I shouldn't bother asking, but
> >I'd like to know.
> >
> >Given the following:
> >----
> >#!/bin/sh
> >fcount=0
> >ls -1 *.mpg | while read filename ; do
> >    fcount=$(expr $fcount + 1)
> >    echo $fcount
> >done
> >echo $fcount
> >----
> >
> >why do I get the following output?
> >----
> >[daniel at alpha ~]$ test.sh
> >1
> >2
> >3
> >4
> >0
> >----
> >
> >I would expect:
> >1
> >2
> >3
> >4
> >4
> >
> >Where is my thinking broken?
> >
> >
>Daniel
>It is obviously a scope issue - but to test this a little further, I set
>the initial value to 2 and got the following results:
>3
>4
>5
>2
>... of course I only have 3 mpg files. No help perhaps.
>Regards
>Fred James
>
>
>_______________________________________________
>http://www.ntlug.org/mailman/listinfo/discuss

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