bash script read line by line

Question

Hello I am trying to create a script that reads my file take all the variable it needs then use it for another command. But it seems that the variables are not being memorized, because I tried a printf instead of running my script and I got an empty output.

here is my code

#!/bin/bash
numparams=$#
params=$*
cat tots.txt | while read;
do  awk '{
regid=$1;
uport=$2;
ongoingcalls=$3;
ingeg=$4;
maxcalls=$5;
if($3<$5) state=0
if($3==$5) state=1
if($3>$5) state=2
}'
/home/send_script.sh -o "$regid $uport $ongoingcalls $ingeg $maxcalls $state"
done

And here is the tots.txt content:

Answer 1

This is because your variables are being set in the subshell you open by saying cat <file> | while .... So when this subshell is done, you cannot access to those variables any more.

Instead, say:

while read; do
    ...
done < tots.txt

Interesting reading: I set variables in a loop that's in a pipeline. Why do they disappear after the loop terminates? Or, why can't I pipe data to read?.

Note also that you seem to have some confusion between awk and shell variables. Whatever you set in awk will remain there, so saying awk '{$var=2}' is two times incorrect: variables in awk are set without the $ ($var will refer to the column number var) and then the var is just in the scope of awk and not available in your shell.

Maybe you want to do something like:

results=($(awk 'BEGIN {print 1,2,3,"a"}'))

So that you create an array results[] that you can later on access.