A doubt on replacing a variable in a text according to a if else condition

Do you have any questions for us, pvinodp?

is this what you are trying to do?

msg="This becomes to crazy \${var1} position now"
fileNameOptionA="temp1"
var1=${fileNameOptionA}
eval "echo $msg"

the variable $var1 does not seem to take the value within the if or else condition.

For both if and else condition I get the following output upon executing "display msg"

This becomes to crazy  position now.

THere is no value in the variable $var1 on both conditions.

$msg is set well before the if condition and hence irrespective of what the outcome is, $msg will always be with the initial value of $var (null)

### this should work ###
fileNameOptionA="temp1"
fileNameOptionB="temp2"
var1=fileNameOptionB

if[condition]
   var1=${fileNameOptionA}
fi
echo "This becomes to crazy ${var1} position now"
###

is this what you are trying to do?
#!/bin/bash
var1=
msg='This becomes to crazy ${var1} position now'
fileNameOptionA="temp1"
fileNameOptionB="temp2"
if [ condition ] ; then
   var1=${fileNameOptionA}
   eval "echo $msg"  #This becomes to crazy temp1 position now

else

   var1=${fileNameOptionB}
   eval "echo $msg"  #This becomes to crazy temp2 position now
fi

@ozo[ 38884932]:
yes you are correct.

But my command is :: dialog --msgbox  "${msg}" 30 30

SO I tried ::  dialog --msgbox  " eval ${msg}" 30 30 ,, but this did NOT work.

Also tried:
 textT=eval $msg
dialog --msgbox  "${textT}" 30 30  // this also dint work

thanks