Shell Programming and Scripting

Hi!

I wanted to use a while loop, like the one below, for checking words extracted by awk to terminate when a specific word appears. Unfortunately whenever I put my code inside the loop I get an error "Expression recursion level exceeded". What does it mean? What recursion? I don't have any recursive calls. I suppose that the problem may be with the number of repetitions which indeed may be very high but the loop is bound to terminate. What can I use instead that would work?

Code:

A="START"
B="END"

while(($A=~$B))
do
{
echo Hello
A=$B
}
done

what is it that you're trying to do and in what shell?
here's a stab in the dark with Bourne shell:

Code:

#!/bin/sh

A="START"
B="END"

while [ "$A" != "$B" ]; do
   echo Hello
   A=$B
done

The shell was tcsh but I used bash to run my scripts. With this syntax everything works perfectly. I tried to use the double parenthesis probably because they worked fine for other control statements... On a side, the code from my first post was also saying 'hello' twice

Thank you for the fix!

Hi,
i have a scenario like
file 1
aaa=ddd
bbb=ccc
ccc =ddd
file 2
aaa=mmm
ttt=yyy
bbb=ggg

using awk function i get the key values for file1 (aaa,bbb,ccc)

sample code
------------
warn_msg=0
call_function() {
while read LINE
do
# key values of file1.txt and file 2.txt is compared, if any invalid parameter, i will set warn_msg=1

if [$? !=0 ]; then
warn_msg=1
fi
done < file2.txt
}

call_function ## calling the function
echo $warn_msg

output
------
0

here the key (ttt) is an invalid parameter.
if any invalid parameter occured within the while loop and if i check the value of warn_msg, it is 1, but after the function completes, the value of warn_msg is assigned to 0 but it should be 1. please provide me an answer.

Here is my solution based on my very limited knowledge. It prints "error" for every key in file2 that doesn't appear in file1.

Code:

#!/bin/bash

awk -F= '{print $1}' < file1 > keys

while read LINE

do
        TMP=`echo $LINE | sed s/=.*//`
        awk -F= -v v=$TMP '{if (v==$1) i=1}END{if (i!=1) print "error"}' < keys
done < file2