Question

Say my input file is tab delimited, how do i identify if $0 contains a word “hello” and it needs to be case insensitive?

here is a hello       whateverColumn2
nonono nonono         whateverItIs
here HeLLo again      mockColumn2

Thanks a lot!

Answer 1

Given your lines in file data.txt:

awk -F"\t" '/hello/ {print $0}' data.txt

will print

here is a hello       whateverColumn2
here hello again      mockColumn2

The -F"\t" sets tab as the field separator for the input lines.

Update (based on request in comments below by OP):

To make this case-insensitive use the IGNORECASE flag:

awk -F"\t" 'BEGIN{IGNORECASE=1} /hello/ {print $0}' data.txt

Note that the IGNORECASE variable is a GNU extension and may not be available in other versions of AWK.

Alternatively, an example using match. In order to make this case-insensitive, the input is converted into lower case:

awk -F"\t" '{if (match(tolower($0), "hello")) print $0}' data.txt

Since match can take regular expressions, the conversion to lowercase may not be necessary with the right regular expression.

Tested with GNU Awk 3.1.6 under Linux