for_file var filename { code }
              This  procedure implements a loop over the contents
              of a file.  For each line in filename, it sets  var
              to the line and executes code.

              The  break and continue commands work as with fore-
              ach.

              For example, the command

                   for_file line /etc/passwd {echo $line}

              would echo all the lines in the password file.

              This procedure is provided by Extended Tcl.