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Need help : KSH>BASH

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Top Forums Shell Programming and Scripting Need help : KSH>BASH
# 1  
Old 10-20-2006
Need help : KSH>BASH
Hello,

I've written a script in KSH, but now it needs to run on a system without KSH, ie sh or bash etc, bash seems best bet, but the simplest of things don't seem to work..

The snippet below is the main issue, basically I'm reading from a dat file and putting fields into arrays..

Dat file example (vm.dat):

132.146.23.111:apitest1:/home/vmware/apitest1/apitest.vmx
132.146.23.112:apitest2:/home/vmware/apitest2/apitest.vmx
132.146.23.113:apitest3:/home/vmware/apitest3/apitest.vmx
132.146.23.114:apitest4:/home/vmware/apitest4/apitest.vmx
Script snippet (runable):

#!/bin/bash
DF=vm.dat
#IFS=":"
count=0
grep -vE "#|^$" ${DF} | awk -F: '{print $1}' | while read F1 F2 F3
do
Filer[$count]=$F1
echo ${Filer[count]} # Debug
Volume[count]=$F2
Config[count]=$F3
(( count +=1 ))
echo $count # Debug

done
#IFS=" "

echo "Filer count = ${Filer[@]} - Count= $count" # Debug

Output example:

132.146.23.111
1
132.146.23.112
2
132.146.23.113
3
132.146.23.114
4
Filer count = - Count= 0


As you can see, it gets read into the vars fine, but seems to forget once out the loop?

I'd expect to see Filer count = 4 - Count= 4#

I suspect I'm being a dumb £"$k somewhere, but to be honest I've never really used BASH but obv. I'm missing something!?

I took the IFS part out just in case that was causing issue , doubt it though!.

Help appreciated...
# 2  
Old 10-20-2006
I think that's not a question of bash/ksh.
That's because of the "while" and the use of pipes that way. The while is executing in a subshell and so, when it finishes, you cannot see the results.
Try this way:
Code:
#!/bin/bash

DF=vm.dat
#IFS=":"

count=0

while read LINE
do
   if [[ "${LINE/#\#*/}" != "" ]]; then
      Filer[$count]=$(echo $LINE | awk -F: '{print $1}')
      echo ${Filer[count]} # Debug
      Volume[count]=$(echo $LINE | awk -F: '{print $2}')
      Config[count]=$(echo $LINE | awk -F: '{print $3}')
      (( count +=1 ))
      echo $count # Debug
   fi
done < $DF

#IFS=" "

echo "Filer count = ${#Filer[*]} - Count= $count" # Debug

Notice the "< $DF".

Regards.
# 3  
Old 10-20-2006
Thanks for the response... Very strange way of doing things?

It looks like you mean that all the 'processing' has to be kept inside the loop? is that right? Is there not a way around this as it seems like alot of over processing? I've seen the declare options, but again didn't fit the bill..

...
# 4  
Old 10-20-2006
Quote:
Originally Posted by itsupplies
Thanks for the response... Very strange way of doing things?
Mine or yours? Smilie
I've just modified your script to make it work. This doesn't mean there are not other ways...

Quote:
It looks like you mean that all the 'processing' has to be kept inside the loop? is that right? Is there not a way around this as it seems like alot of over processing? I've seen the declare options, but again didn't fit the bill..

...
Nop. I did not mean that. It's not compulsory. As I said above, there are, for sure, other ways to do it.

What I mean is that parent shell won't see his child's variables Smilie

Regards.
# 5  
Old 10-20-2006
Sorry, I meant BASH way of things Smilie I've been using KSH for many many years and have a nice comfort zone, I didn't think BASH (bash-2.05-8.2) would be to far from it. Trouble is most of my functions/loops are base on the way it works in KSH, so to suddenly not be able to hold onto VAR defs from loop to loop means big headaches Smilie

Once you setup a VAR in KSH, its pretty much global from go, is there anyway to acheive this in BASH?

Thanks again for your time Smilie
# 6  
Old 10-20-2006
Well, that's the way bash behaves. Anyway, you can use named pipes:

Code:
#!/bin/bash
DF=vm.dat
#IFS=":"
count=0
mkfifo pipe
grep -vE "#|^$" ${DF} | awk -F: '{print $1}' > pipe & 
while read F1 F2 F3
do
   Filer[$count]=$F1 
   echo ${Filer[count]} # Debug
   Volume[count]=$F2
   Config[count]=$F3
   (( count +=1 ))
   echo $count # Debug
done < pipe
rm pipe
#IFS=" "

echo "Filer count = ${Filer[@]} - Count= $count" # Debug

Perhaps this is the easiest way to port your ksh scripts to bash. Notice that now there's no subshell... Smilie

Regards.
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