如何在PHP中回显at（@）符号？

Using PHP, how can I echo an at (@) sign?

Ultimately, I'm trying to print out an e-mail address to a shell, that should look like this: 'user@site.com', but it ends up looking like this: 'usersite.com'.

I see that all these (echo, exec, shell_exec, sprintf, vsprintf) behave like this so I suspect I need to escape it in some way?

I think you are doing something wrong, there is no escaping neccessary:

echo "user@site.com";

enter image description here

When echoing to shell, you need to use double quotes if you are using any special characters, @ included.

This will work:

echo "user@site.com/n";

This will not:

echo 'user@site.com/n';