Shell Programming and Scripting

Is it possible to make the search in regular exprecion or in matching parts of sed, nawk and others to IGNORE the case of the search string?

I mean, like if used 'grep' with -i option:
> grep -i "abc" file

I would like to be able to do the same, say, by nawk:
> nawk '/abc/ {print $0}' file
or sed:
> sed -n '/abc/ p' file
or for expancion:
> echo ${var/abc/ found }
- but all that is the case sensitive!

Is there a way to make all those searches not case sensitive, exept having every letter in the way, like [Aa] ?

Appreciate your help!

Code:

 
/regex/i

Ed: Now that I've said that, I'm not so sure it would actually work for the apps you mention.

gsed (GNU sed) V3.02 has the I flag.
gawk had the IGNORECASE option.

In sed (regular, standard sed, not some obscure derivate) it is a little cumbersome, but can be done:

Code:

sed -n '/[Rr][Ee][Gg][Ee][Xx]/p'

Alternatively, thefollowing could also work: copy every line to the holdspace, use the "y"-subcommand to translate the phrase in qestion to all upper or lower case and then search for that. If it is found, replace the pattern space with the hold spaces content (which is the unchanged line) and print it:

Code:

sed -n 'h
        y/REGX/regx/
        /regex/ {
             x
             p
        }'

I hope this helps.

bakunin

In nawk you can use the tolower function to do regex matching (I just saw this in another thread a minute ago):


Equivalent to grep -i abc (I hope):

nawk '
tolower($0) ~ /abc/ {print }
'