Recently I come across a requirement to search for lines in a given file/files where the search term is mix of capital letters and small letters. Normally when we search with awk it search exactly what we try to search but not ignoring case. We can use grep to accomplish this task as sown below.

	grep -i 'available' files | awk '{print $1,$2}'

But I don't want to use grep to do this as there is a way we can accomplish with just awk. We can specify ignoring case to AWK in three ways as mention below.

  1. 			Use AWK builtin variable called IGNORECASE
    			enable ignore case switch with search pattern
    			Use not so sophisticated method of using both cases in search term

Let see these three in examples.

Example1: Search for a word 'available' which some times written as Available or AVAILABLE. Using IGNORECASE AWK inbuilt variable example as below

	awk 'BEGIN{IGNORECASE=1} /available/{print $1}' filename

BEGIN is an AWK keyword which is useful to execute awk code before actual AWK script. We are setting IGNORECASE before our actual AWK code execution.

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Example2: Search for word 'available' using 'i' switch so that my match will have both cases

	awk '/available/i {print $1}' filename

if you observe after serach pattern we given /i which will help us to ignore case with our search term.

Example3: Search for 'available' word with combination of cases which will not work in all the cases

	awk '/[aA][vV][aA][iI][lL][aA][bB][lL][eE]/ {print $1}' filename

Hope this helped some one when trying to shorten your code.