sed help plz
 

I am looking to use sed in a script. I have searched through the docs and cannot find what I am looking for.

If I have an email address like frustrated_sed_user@smtp1.mail.linux.com. How do I get the topmost domain out? (ie linux.com)

RK

awk is a better tool for extracting fields:

The "-F." is telling awk to use dot as the field separator instead of white space. The dot in quotes in the print section is adding the dot back to the output as awk stripped it out when it broke the fields up. Fields 3 and 4 are being printed before and after the dot respectively.

Well, I can tell I'm warmer...

How do I do a reverse search?

If I do:
I get linux.com just like I want, but if I have:
I get com.

Further clarification: I'm looking for a more general email address filter, not something that only works with that one string.

Oh and thank you very much for your reply. I think awk may be what I need, but geez that's a lot of documentation.

RK

NF = number of fields so $NF would be last field and $(NF-1) would be field before last field. So long as you have at least 2 fields it should work for any address that ends in the domain you want.

Really good tutorials here---SED, AWK, and more:
http://www.grymoire.com/Unix/

Beats reading man pages.....;)

Being not well versed in awk, I only use it when data is (extremely) well structured - as in the cases above.
Must admit I have a leaning toward regex in that it can be used to extract data from anywhere in a record - building a (fool-proof) regex for this could get challenging though.
Perl might be a better option than sed.

Another method

I wouldn't use awk here, but you can. Here's how I would do it to make it more useful:

So basically using 'rev' is a good idea here. It reverses lines character by character.

but here, you make extra calls to rev, cut.

well, i don't know why you think without regex you can't extract data from anywhere in a record :)

The only extra call is to 'rev'. You can use awk instead of cut:

Or you could use just awk:

as jlightner said earlier

NF is the number of fields, so NF is the last field, and NF-1 is the next to last field.

Whichever way you want to do it, there are so many ways.

still the same thing. you have to call rev 2 times, awk 1 time. See post #4 by jlightner. that's common way to get awk fields from the back.

Oh yeah, I guess I missed that post, and posted the same thing just a second ago. Oh whatever, 0.003 sec is that important.

yes, there are many ways, but don't choose the ones less obvious. :)

My second post did it without having to "rev" anything. I just changed the variables to be relative to number of fields rather than explicit 3 and 4.