Extension Example (The GNU Awk User’s Guide)

From Get docs

17.6 Example: Some File Functions

No matter where you go, there you are.

Buckaroo Banzai

Two useful functions that are not in awk are chdir() (so that an awk program can change its directory) and stat() (so that an awk program can gather information about a file). In order to illustrate the API in action, this section implements these functions for gawk in an extension.

Internal File Description    What the new functions will do.
Internal File Ops    The code for internal file operations.
Using Internal File Ops    How to use an external extension.