Shell Programming and Scripting

Hey guys. I know pratically 0 about Linux, so could anyone please give me instructions on how to accomplish this ?

The distro is RedHat 4.1.2 and i need to find and replace a multiple lines string in several php files across subdirectories.

So lets say im at root/dir1/dir2/ , when i execute the script it should search and replace a piece of code on php files inside this directory and its subdirectories.

The closest i found i think it was this:

Code:

Paste this into a file ‘renall’ and make it executable (chmod u+x renall): #!/bin/sh
 if [ $# -lt 3 ] ; then
   echo -e “Wrong number of parameters.”
   echo -e “Usage:”
   echo -e ”  renall ‘filepat’ findstring replacestring\n”
   exit 1
fi
 #echo $1 $2 $3
for i in `find . -name “$1″ -exec grep -l “$2″ {} \;`
do
mv “$i” “$i.sedsave”
sed “s/$2/$3/g” “$i.sedsave” > “$i”
echo $i
#rm “$i.sedsave”
done

But the string i need to find and replace have multiple lines, so i dont know how to put it in this script.

Also i dont know how to save and execute this script

EDIT: AH and by the way, i need to only DELETE the piece of code from these PHP files, i dont need to replace it with something else...

Could anyone please give me detailed instructions on this ?

Thanks in advance!