patrix is a simple command line client for Matrix written in perl. It can send text messages to rooms. I use it to send Zabbix alerts to a Matrix room, a bit like sendxmpp can do with XMPP.
* --server: the HS you want to connect to. Default is https://matrix.org
* --access_token: can be used instead of --user and --password
* --room: the room to which the message must be sent
* --message: the text message you want to send. If you send something on stdin, it's assumed to be the text to send and this option is ignored
* --debug: if present, will be verbose
* --notice: send a notice instead of a message (more or less the same but the client can display it differently. Riot for example will not notify you for notices)
* --conf: path to a conf file. Default conf file is ~/.patrixrc