Recent gnome-terminal handles these much more safely. If you paste in a newline, whether from primary or clipboard, the terminal puts a newline into your command, but doesn't press enter for you.

> terminal puts a newline into your command, but doesn't press enter for you.

I'm having difficulty imagining this. I know of some who warn on multiline paste, but how exactly is it possible to "put a newline" but not "press enter"? Just emit a newline as output without sending as input?

You can do this without pasting. Ctrl-Q Ctrl-J at the bash prompt inserts a newline into the command line without executing it. This is useful for multiline scripting commands.

That's a readline feature (quoted insert C-q). So the terminal is smart enough to detect readline and then quote the newlines?

Neither gnome-terminal nor bash link against readline. I'm pretty sure they just copied the feature; it's not that they use readline in any way.

There's lots of other programs that use C-q for quoting, for example emacs, and readline probably copied it from there in the first place.

When pasting text, it's a different code path than quoting. The terminal surely knows when text is being pasted. If nothing else, a simple heuristic based on typing speed is enough to tell apart typing and pasting.

I investigated some more and this is called "bracketed paste" and both the program and terminal must support it (program must enable it). https://invisible-island.net/xterm/xterm-paste64.html