To extract text between two regular expressions, use `sed -n '/first_regex/second_regex/p'`.

For instance, to ad-hoc extract the function definition of the test `tsync_override_log_subdomains_off`, use:

```
sed -n '/TEST_F(audit, tsync_override_log_subdomains_off)/,/^}/p' \
    tools/testing/selftests/landlock/audit_test.c
```

This assumes that the function ends with a single `}` on an individual line.
But that tends to be a given.

`awk` offers similar features.
This invocation finds the definitions of static functions with `report_fixup` in their names, and prefixes these findings with the filenames:

```
awk '/^static.*report_fixup/,/^}/ { print FILENAME, $0; }' *.c
```

But well, `awk` is awkward.