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AWK -> getting "global" vars

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# 1  
Old 05-26-2006
AWK -> getting "global" vars
Hello,

presently, I'm calling nawk from my main script and have nawk defined in one file. So I call nawk like this
nawk -f file input

This file defines how to separate mails in /var/mail/$user and show 1 at a time. However, I would also like to do other actions (delete message, forward message, etc), but I don't want to do separately. I mean to create a new "nawk" file just for forwarding... .

The thing I would like is to pass a variable into this nawk file so I can decide what to do (print, forward, delete) and have it in one place. But the problem is I have no clue how to pass info and get it in nawk file.

I hope there is someone with a clue.

Thx.

Peto
# 2  
Old 05-26-2006
nawk -v action='print' -f file.awk input.txt

file.awk:
Code:
BEGIN {
   # if no action is specified on the command line - default to "print"
   if (action == "")
     action="print"
}
{
   if ( action == "print" )
       doPrint
   if ( action == "forward" )
      doForwarding
   if ( action == "whatever" )
      doWhatever   
}

Last edited by vgersh99; 05-26-2006 at 01:55 PM..
# 3  
Old 05-26-2006
Exactly what I wanted...Smilie

Thanks a lot...

Peto
# 4  
Old 05-26-2006
Is it possible to get a value from NAWK?
so I can print every message and let user choose which mail to delete and after that I would get which mail he chose and after that I would call nawk again with action=delete mail=value...
# 5  
Old 05-26-2006
Quote:
Originally Posted by petoSVK
Is it possible to get a value from NAWK?
so I can print every message and let user choose which mail to delete and after that I would get which mail he chose and after that I would call nawk again with action=delete mail=value...
Code:
#!/bin/ksh
eval $(nawk -v action='choose' -f file.awk input.txt)
echo "ChosenRecord->[${chosenRecord}]"

file.awk:
Code:
BEGIN {
   # if no action is specified on the command line - default to "print"
   if (action == "")
     action="print"
}

function doChoose()
{
   # here we're doing the "choosing" - Once a record is chosen...
    printf("chosenRec=%d\n", numberOfChosenRecord);
}
{

   if ( action == "choose" )
       doChose

   if ( action == "print" )
       doPrint
   if ( action == "forward" )
      doForwarding
   if ( action == "whatever" )
      doWhatever   
}

# 6  
Old 05-27-2006
When I write
eval $( nawk -f forward.awk /var/mail/$USER )
it wants more input so I have to end it with double ^D .

Also I'm not sure if I understand it correctly. What does eval do in this example? Does it return value which was returned from nawk? so I can get it by using $? .
How nawk return a value? : return 55 ?

Is it possible to use "global variables" that I can modify also in nawk and have it changed in parent script.
# 7  
Old 05-27-2006
what shell are you using?

try:
eval `nawk -f forward.awk /var/mail/${USER}`

for the rest of the questions (if it's the ksh you're using):
'man ksh'.

And 'no' - you cannot modify parent vars from the child process - at least not directly from 'awk' to shell - that's the whole point of using 'eval'.
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