David Turetsky wrote: >>:%s/^[a-z]:[0-9]/#/g > Try something like: > %g!/^#/s/^/#/ > Steve Lamb replied: > Personally I'd do it this way: > %s/\(.*\)/#\1/g David responded: Steve's approach would put a # in the front of ALL lines whether or not they initially contain an existing # to begin with If that is what you wanted to do, you could: %s/^/#/