[NTLUG:Discuss] Simple bash shell question

[. Daniel]

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?

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