Documentation request: sed, grep and other regexs

[Zenaan]

Both sed and grep (and possibly others, eg awk) provide regular expressions.

sed doco is very sparse

grep actually has a page of "Usage" examples in its info docs

awk has a whole manual

Perhaps sed and grep could each have "See Also" entries which point to each 
other, and to awk and perl possibly.

Many man pages have a See Also section. sed and grep man and info pages don't 
have this.

For someone learning a new tool, such cross references can be very useful.

Somewhere, it would be good to have a comparison of the regular expressions of 
the various tools - sed, awk, grep, perl - to teach the differences, if any, 
and commonalities.

Anyway, I know the next response would naturally be "can you write such a 
document" - so I'll get back to you on that one when/ if I do. I would like to.

Thanks for great programs, and best regards
Zen