Mastering Linux Shell Scripting - Second Edition

AWK variables

We saw how to use data fields such as $1 and $2. Also, we saw the NR field, which holds the number of processed lines, but there are more built-in variables that AWK offers to simplify work more and more.

• FIELDWIDTHS: Specifies the field width
• RS: Specifies the record separator
• FS: Specifies the field separator
• OFS: Specifies the output separator, which is a space by default
• ORS: Specifies the output separator
• FILENAME: Holds the processed file name
• NF: Holds the line being processed
• FNR: Holds the record which is processed
• IGNORECASE: Ignores character case

These variables can help you a lot in many cases. Let's assume that we have the following file:

John Doe 15 back street [phone] Mokhtar Ebrahim 10 Museum street ...