" Check for changed timestamp (unless it was never set, or forced write)
if !bang && edited && timestamp != "" && time(filename) != timestamp
then error file's timestamp has changed
" Maybe make a backup
if backup && !newfile
then {
 switch os
 case unix eval ! cp (filename) (filename).bak
 default   eval ! copy (filename) (dirname(filename) / basename(filename)).bak >NUL
}