CVS and E*Trade both refused to accept my fairly standard user@mydomain.info address during initial registration, but had no issue changing to that address once the account was created. It would be nice if their internal teams communicated a bit better.
The full email address syntax described in the RFC cannot be precisely matched with a mere regular expression due to the support for nested comments. The need to track arbitrarily deep nesting state makes it a non-regular language.
If you remove the comments first the remainder can be parsed with a very complex regex, but it will be about a kilobyte long.
They ruled that people acting together have all the same rights that they would have acting individually, and that preventing someone from spending money on producing and promoting their speech effectively prevents them from being heard. Which are both perfectly true, common-sense statements.
Examples of local commands I might run in tmux could include anything long-running which is started from the command line. A virtual machine (qemu), perhaps, or a video encode (ffmpeg). Then if I need to log out or restart my GUI session for any reason—or something goes wrong with the session manager—it won’t take the long-running process with it. While the same could be done with nohup or systemd-run, using tmux allows me to interact with the process after it’s started.
I also have systems which are accessed both locally and remotely, so sometimes (not often) I’ll start a program on a local terminal through tmux so I can later interact with it through SSH without resorting to x11vnc.
Not the GP but I also use tmux (or screen in a pinch) for almost any SSH session, if only as insurance against dropped connections. I occasionally use it for local terminals if there is a chance I might want a command to outlive the current graphical session or migrate to SSH later.
Occasionally it’s nice to be able to control the session from the command line, e.g. splitting a window from a script. I’ve also noticed that wrapping a program in tmux can avoid slowdowns when a command generates a lot of output, depending on the terminal emulator. Some emulators will try to render every update even if it means blocking the output from the program for the GUI to catch up, rather than just updating the state of the terminal in memory and rendering the latest version.
In what sense do you think this isn’t following the email standard? The plus sign is a valid character in the local part, and the standard doesn’t say how it should be interpreted (it could be a significant part of the name; it’s not proper to strip it out) or preclude multiple addresses from delivering to the same mailbox.
Unfortunately the feature is too well-known, and the mapping from the tagged address to the plain address is too transparent. Spammers will just remove the label. You need either a custom domain so you can use a different separator (‘+’ is the default but you can generally choose something else for your own server) or a way to generate random, opaque temporary addresses.
If you want to talk about non-compliant address handing, aside from not accepting valid addresses, the one that always bothers me is sites that capitalize or lowercase the local part of the address. Domain names are not case-sensitive, but the local part is. Changing the case could result in non-delivery or delivery to the wrong mailbox. Most servers are case-insensitive but senders shouldn’t assume that is always true.