wait_on mit Homebrew, MacPorts installieren

Projektlinks

• Homepage

Befehle und Aliase

• wait_on

Projektgeschichte

The FreeBSD manual page gives the clearest project history: `wait_on` was written by Andrew Stevenson in January 2002 under FreeBSD 4.4. Its design is tied directly to kqueue, the BSD kernel event-notification facility that had recently made file, directory, and descriptor events available without busy polling.

Wie es verwendet wird

The command waits on one or more files or directories and exits when a requested event occurs. The manual gives examples such as watching a mailbox for writes, waiting for files to arrive in an incoming FTP directory, or using `-i` and `-t` so a script can tell which watched path changed or timed out.

Internally, `wait_on` uses kqueue's vnode notifications, including events for writes, extension, deletion, renames, link-count changes, attribute changes, and revocation. That makes it a compact bridge between shell scripting and kernel event delivery on systems with kqueue.

Warum Paket-Nerds sich dafür interessieren

This is a classic small Unix package: one command, one system primitive, and a clean scripting use case. It is historically interesting because it predates the later wave of cross-platform file-watcher tools and shows early BSD users solving shell automation without periodic `stat` polling.

Zeitleiste

• January 2002: `wait_on` was written under FreeBSD 4.4 by Andrew Stevenson.
• 2000s onward: the command remained useful as a shell-level wrapper around kqueue file and directory events.

Related projects

• The closest related primitive is kqueue itself. In the broader file-watching family, `wait_on` overlaps conceptually with inotify-based Linux tools and higher-level cross-platform watchers, but it stays intentionally close to the FreeBSD kernel interface.

Quellen

• https://man.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2
• https://man.freebsd.org/cgi/man.cgi?query=wait_on
• https://www.freshports.org/sysutils/wait_on/