test -t 1 returns true when not attached to tty

[zx8]

Fish

$ fish --version
fish, version 2.7.1-836-g6f1ae79a

$ function is_attached_to_terminal; test -t 1; and echo yes; or echo no; end

$ echo | is_attached_to_terminal | cat
yes

Bash

$ bash --version
GNU bash, version 4.4.19(1)-release (x86_64-apple-darwin15.6.0)

$ is_attached_to_terminal() { test -t 1 && echo yes || echo no; }

$ echo | is_attached_to_terminal | cat
no

[faho]

Yup. Duplicate of #1228. Either use isatty or command test.

[faho]

Okay, I'm going to reopen this one and then fix it separately from #1228.

The reason for that is that I'm not going to make test actually redirect these file descriptors, because that's a complete waste.

Instead, I'm going to have test check what you mean, which is if the stream goes to a terminal even if the fd doesn't.

And that's a much bigger problem with the actual device files because there are a bunch of them and I don't want to parse them out. To a first approximation, nobody cares what test -c /dev/fd/0 does. They care if stdin is a tty, and test -t 0 or isatty stdin are the thing to check.

If anyone cares enough to fiddle with /dev/fd/x and /dev/stdout and such, be my guest.