How to use word boundaries in awk without using match() function?

Question

I want to add word boundaries to this awk command:

awk '{$0=tolower($0)};/wordA/&&/wordB/ { print FILENAME ":" $0; }' myfile.txt

I tried adding \y at left and right of wordA and wordB but it didn't work in my tests.
I tried this: /\ywordA\y/&&/\ywordB\y/

Thanks all!

(ps: I'm new to awk so I was trying to avoid the match() function.)

Neela

Your curly-brackets don't seem to be balanced properly; you have more }s than {s. – Zanezaneski

I only know one version of awk that understands \b word boundaries: the one you get when you run it through a2p. :) – Monocarpic

I also tried \b and \<wordA\> but not working (mac osx). – Neela

@Neela You don’t understand. a2p someawkcode | perl is the awk-to-perl translator. That way you can get real perl regexes. – Monocarpic

Answer 1

You want to use gawk instead of awk:

gawk '{$0=tolower($0)};/\ywordA\y/&&/\ywordB\y/ { print FILENAME ":" $0; }' myfile.txt

will do what you want, if your system has gawk (e.g. on Mac OS X). \y is a GNU extension to awk.

Schenk

Answer 2

1. GNU awk also supports the \< and \> conventions for word boundaries.
2. On a Mac, /usr/bin/awk version 20070501 does not support [[:<:]] or [[:>:]]

3. If you're stuck with a recalcitrant awk, then since awk is normally splitting lines into tokens anyway, it might make sense to use:

   function word(s, i) { for (i=1;i<=NF;i++) {if ($i ~ "^" s "$") {return i}}; return 0; }

So, for example, instead of writing

/\<[abc]\>/ { print "matched"; }

you could just as easily write:

word("[abc]") { print "matched"; }

Sodomy

Answer 3

This might work for you on Mac OS X:

awk '{$0=tolower($0)};/[[:<:]]wordA[[:>:]]/&&/[[:<:]]wordB[[:>:]]/ { print FILENAME ":" $0; }' myfile.txt

But as it won't work on linux you're best off installing GNU awk.

Jonniejonny

As of MacOS Mojave, this doesn't work for me. (^|[^A-Za-z0-9_]) works for a starting word boundary and ([^A-Za-z0-9_]|$) for an ending one (maybe exclude the underscore or perform other tweaks depending on your use case). I don't think this is portable between Awks, either, unfortunately. – Dupondius