regexp case-insensitive

[Arnold Robbins]

In article <6801 at uceng.UC.EDU> schriste at uceng.UC.EDU (Steven V. Christensen) writes:
>Hi, I'm writing an AWK script which must search for the occurrance of
>user-specified text. Right now it is:
>
>/text/ {do something}
>
>But I need /text/ to be case insensitive. What do I need to do?

There are several options.  The most portable is to put your awk program
into a pipeline on the other end of tr.  Assuming a System V tr

	tr '[A-Z]' '[a-z]' < data | awk '/text/ { stuff }'
	# use	tr A-Z a-z 	on a BSD system

where your text is in lower case.  If you have the very latest at&t nawk
(available from the ATT Toolchest), you can use the tolower() built-in
function to map your data into one case, like so:

		{ $0 = tolower($0) }
	
	/text/	{ stuff }

If you have or can get gnu awk, you set IGNORECASE=1 in a BEGIN block
or on the command line, and the regexp match will be done ignoring case.
Gnu awk also supports the tolower and toupper functions.  If you don't
wish to use the tr example, those are your next best bet.
-- 
Arnold Robbins				AudioFAX, Inc. | Laundry increases
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