Very Computer

Hi,

I got the following codes in my shell script (using /bin/sh) :

#!/bin/sh

this_count=0;export this_count
while read ip other
do
   if [ $PREV_IP != $ip ]
   then
      PREV_IP=$ip;export PREV_IP
      printf "IP %s has visited\n" $ip
      echo $this_count
      this_count=`expr $this_count + 1`;export this_count
   fi
done < $TEMP_FILE
echo value of count is $this_count

I expected that I could get the value of count "this_count" after loop
but actually, I only got "0" as the value, no matter how much iteration
the loop has performed.

Can anyone tell me what's happened to this shell script? How can I
retrieve values from the loop?

Thanks a lot.

--
Patrick

Quote:

> Either put an "exec <$TEMP_FILE" before the loop and
> take it off the "done", or use ksh.

In addition to the other fixes...

|> #
|> #   #!/bin/sh
|> #
|> #   this_count=0;export this_count

You shouldn't need to export these variables.

|> #      if [ $PREV_IP != $ip ]

In the first iteration. $PREV_IP will evaluate to nothing, and you will
get a syntax error. Reference it like this

        if [ "$PREV_IP" != $ip ]

It wouldn't hurt to do this with ip as well.

./tmp.sh: [: !=: unary operator expected

|> #   done < $TEMP_FILE

TEMP_FILE is undeclared. Perhaps is is meant to be provided in the
environment. Either way, you should check for its presence when the script
starts up.

$ TEMP_FILE=tmp.tmp ./tmp.sh
IP 123.123.123.123 has visited
0
IP 234.24.324.243 has visited
1
value of count is 2

--

Website (recently moved) http://homepages.paradise.net.nz/~cameronk/
--

Besides, I would like to supplement the information that the variable $TEMP_FILE
has been defined in the shell but I did not include the statement in my sample.

--
Patrick