Re: using a variable to help define a regular expression

"Janis" wrote in message 
news:18784f90-e0de-450c-8c93-a91d5dee36d4@[EMAIL PROTECTED]
> > i guess it's instructive to me that this appears non-trivial (and even
a 
> > bit
> > controversial?) in a language as mature as awk.
>
> No, it is trivial. Any "non-triviality" here stems from shell
> quoting issues and from mixing shell level and awk level code.
> I also think it hasn't been controversial (at least comparing
> suggestions amongst posters of a similar experience).
>
> (Some non-trivialities will appear if your dynamic regexps
> contains regexp meta-characters.)

thanks, that was perhaps careless of me. maybe we could agree on "trivial"

in theory, sometimes non-trivial (or non-portable? or potentially 
troublesome in some cases?) in practice.

speaking of which, i now got this to work in cygwin and under linux

    echo "/a/|/b/" | tr '|' '\n' | awk -v base="a" '($1 ~ "/"base"/") 
{print}'

so I'm a happy camper.

> (BTW, since it hasn't been mentioned yet; to avoid problems
> with quoting you can put the awk program in a file and call
> it using awk's -f option. As a side effect you are forced to
> use a cleaner and more robust way to pass shell variables.)

good to know, thanks. i have occasionally used awk that way in the past,
but 
get a lot of great mileage with one-liners in the middle of pipes. the 
challenge becomes how to file away the useful ones for future recycling.
:)

cheers, Tim