Find and replace in shell scripting

Question

Is it possible to search in a file using shell and then replace a value? When I install a service I would like to be able to search out a variable in a config file and then repl

Answer 1

filepath="/var/start/system/dir1"
searchstring="test"
replacestring="test01"

i=0; 

for file in $(grep -l -R $searchstring $filepath)
do
  cp $file $file.bak
  sed -e "s/$searchstring/$replacestring/ig" $file > tempfile.tmp
  mv tempfile.tmp $file

  let i++;

  echo "Modified: " $file
done