CODEWITHSUNDEEP
awk
ceving
ceving

Reputation: 23794

How to use the FS in a regular expression?

Is it possible to reference the field separator FS in a regular expression of awk as it is possible in the body of an expression?

awk -F: '/^FS/{print FS}'

Upvotes: 2

Views: 495

Answers (2)

Tom Fenech
Tom Fenech

Reputation: 74596

You can't use any variable inside / / - FS is no exception.

Your script could be written using ~ which allows you to convert a string into a regular expression:

awk -F: '$0 ~ "^" FS { print FS }'

Upvotes: 6

hek2mgl
hek2mgl

Reputation: 157947

When the field separator is at the first column of the line, NF must be greater than 1 and the first field have a length of zero:

awk -F: 'NF>1 && !(length($1)) {print FS}'

Upvotes: 1

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