Replacing certain field

hi all,
i am having a script file which contains lot of fields and commands.

let's say i have the following word (example1) spread all over the script in every place, how can i replace it with the word (example2)?....the only way i know is to use to either delete the word (example1) and write the new word (example2) or to replace word by word!!!

Do you have a better way for that????!!!

Thanks for your help....

Does the following fulfill what you want to do

sed "s/example1/example2/"  file