AWK: convert into lower or upper cases

In order to convert a bash variable to lower case with awk, just use this command:

1 2	a="UPPER CASE" echo "$a" | awk '{print tolower($0)}'

If you want to convert the content of a file (called data.csv) to lower case:

1	awk '{print tolower($0)}' data.csv

Of course to convert into upper case, simply use the function toupper() instead of tolower().

Note also that a better tool to avoid issues with special characters might be the tr unix command:

1	tr [:upper:] [:lower:] < input