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mq(4) — message queue ==== Mq serves a 9p file tree representing groups of buffered two-way data streams for multiple readers and writers accessible through the standard read(2) and write(2) file I/O interface. Overview ---- Streams may be organized within an arbitrary file tree structure, which provides a means of namespacing and grouping. <group> <group>* <stream>* order ctl A directory denotes a group of streams. Any number of streams and sub-groups may be created within a group. Grouped streams share configuration and an order file. The read-only meta-stream called order provides ordering information for data written to streams within a group. Special readers such as `mq-cat(1)` can tap into this stream to retrieve data coming from multiple streams in the same order it was written. See the [`mq(4)`][mq] manual page for a complete description of supported data modes, queue replay options, usage reference, and other details. Examples ---- Mount the `mq(4)` file server and use it to persist an `rc(1)` shell session. mq -s detach mount -c /srv/detach /n/detach mkdir /n/detach/rc cd /n/detach/rc echo replay all >ctl touch fd0 fd1 fd2 rc -i <fd0 >>fd1 >>[2]fd2 & Attach to the shell: cat fd1 & cat fd2 & cat >>fd0 The program [`pin(1)`][pin] provides a polished interface for persisting program sessions. It also makes use of the data ordering feature for faithful reproduction of session history. The program `mq-cat(1)` is an example of an ordered multi-stream reader. [mq]: http://a-b.xyz/95/34b5 [pin]: http://a-b.xyz/9b/2151