execline is a (non-interactive) scripting language, like sh, but its syntax is quite different from a traditional shell syntax. The execlineb program is meant to be used as an interpreter for a text file; the other commands are essentially useful inside an execlineb script.
Binary packages can be installed with the high-level tool pkgin (which can be installed with pkg_add) or pkg_add(1) (installed by default). The NetBSD packages collection is also designed to permit easy installation from source.
The pkg_admin audit command locates any installed package which has been mentioned in security advisories as having vulnerabilities.
Please note the vulnerabilities database might not be fully accurate, and not every bug is exploitable with every configuration.
Problem reports, updates or suggestions for this package should be reported with send-pr.