Linux Journal - September 2011

to functions, as long as the function knows what to expect.

5. The switch/case statement is enabled by default. gawk has had switch/case for a long time, but it had to be enabled at build time, and the default was not to do so; now it’s enabled automatically.

6. gawk now supports defining fields based on field content, instead of based on the separators between fields. A new variable, FPAT, is used. When you assign a string containing a regular expression to FPAT, gawk begins splitting fields such that each field is the text that matched FPAT. (Normal field splitting is based on the text in between fields matching the regular expression in FS.) This is useful for many kinds of data where FS-based matching just doesn’t work.

The new patsplit() built-in function provides access to this functionality for strings besides the input record. It is the analogue of awk’s regular split() function. Additionally, patsplit() lets you capture the text of the separators between fields.

7. Standard awk provides only one-way pipelines, either to or from another process. gawk provides a notation for opening a two-way pipeline to a co-process. gawk uses the same notation with special, internally recognized filenames, to provide TCP/IP communication