Comment by mg

You could also use vim in a loop. Say you want to replace "hello" in all files in the current dir with "world" and confirm every replace, then you would do:

    for f in $(grep -l 'hello' *); do vim -c ':%s/hello/world/gc | wq' "$f"; done

Or if you want to use some more vim magic, this simpler command will do the same:

    vim -c "argdo %s/hello/world/gce | update" -c "qall" *

"argdo" will do the replace command for each file, the additional e modifier in gce will ignore files that do not contain the search string and the second command "qall" is to quit vim after the work is done.