WordPress control from the command line. Written in bash. At the time of writing, I still use it, and it saves me a lot of time... but I don't actively develop it; but patches/pull requests are welcome, if you like them. But don't ask for support, or report issues; as I say, I'm not actively developing.
Was formerly sold (with a GPL licence; is now MIT) at wordshell.net (probably the domain will be bought by someone else in future, so please do not assume that I still control it), but after end-of-life, that site was archived to remove the maintenance burden. So, the manual that was there is gone (but you can probably get it at the Internet Archive). You can also do wordshell --help (or just read the source).
You should probably use WP-CLI instead. But WordShell still has a few interesting features that I think aren't in WP-CLI yet. e.g. Difference analysis and recording and auto-patching; and accessing sites via FTP/SFTP.