Search for a key and replace the value in a file

[tulsantide]

Hi,

I have 2 files as below.

file1.txt
=========
var1=value1
var2=value2


file2.txt
==========
var1=xxxx
var2=yyyy
var3=zzzzz

I need to look for each key from file1.txt in file2.txt and then replace the value of that key in file2.txt with the value that is in file1.txt. The final result should be as below.
==========
file2.txt
==========
var1=value1
var2=value2
var3=zzzzz

Here is the code that I have. The following "sed" command works fine from command line but not inside the script. Please let me know if I'm doing anything wrong.
===============
#!/bin/sh
cat "file1.txt" | while IFS== read key value
do
echo "key='$key' value='$value'"
sed -i '/^${key}=/s/=.*/=${value}/' file2.txt
done

 

[tulsantide]

Never mind it is working after putting double quotes in the sed command