Substitution using SED

Hi ,

I am stuck up in the below scenario:-

I need to read a file name (eg A.txt) name frm another file (eg B.txt) and then I need to search for a particular expression in A.txt and substitute it with another expression.

How can I use SED inside SHELL Scripting and command prompt as well to execute the above problem.

Thanks in Advance,
SD.

Or better yet...
What have you tried to accomplish this?

Can you provide some example programming you have written and/or "rough" script commands to accomplish your task?

#!/bin/sh

FILE="$1"

echo ############################
echo $FILE
echo ############################

exec 3<&0
exec 0<$FILE

while read line

do

echo ############################
echo $line
echo ############################

FILE1="$line"

echo ############################
echo $FILE1
echo ############################

sed 's/feature\/frame\/work/vobs\/syscomp02\/comm\/work/' $FILE1

done
exec 0<&3
+++++++++++++++++++++++++++++++++++++++++++++++++++++

Where $1 is the input file which has the name of files to be edited.