What is the rational?

[runeimp]

I'm curious what use case you had where the terminal size was needed but not available, such as in a non-interactive shell?

BTW, you can use the POSIX standard utility stty , on everything but Windows from what I can tell, to get the terminal size.

Subwindow of KiTTY

$ stty size
35 128
$ stty size &> x; cat x
35 128

If you just want the cols

$ stty size | cut -d' ' -f2
128

iTerm2

$ stty size
25 78
$ stty size &> x; cat x
25 78

tmux in iTerm2

$ tput cols
78
$ tput lines
24
$ stty size
24 78
$ stty size &> x; cat x
24 78

Apple Terminal

$ tput cols 
120
$ tput lines
36
$ stty size            
36 120
$ stty size &> x; cat x
36 120

[Alhadis]

I came here to point this out too.

Note that it's also possible to query the dimensions of terminal windows other than the current one:

$ stty -f /dev/ttys001 size
$ stty -f "`tty`" size

[jpmhouston]

"Rationale"?

Not (just) trying to be an a**hat, I seriously couldn't figure out what the title meant before opening and thought it was math related.

Nonetheless, up-voted.

[sindresorhus]

I needed it for term-size.

---

// x.js
const childProcess = require('child_process');

childProcess.execFile('stty', ['size'], (error, stdout) => {
	console.log(error || stdout);
});

$ node x.js
Error: Command failed: stty size
stty: stdin isn't a terminal

    at ChildProcess.exithandler (child_process.js:308:12)
    at ChildProcess.emit (events.js:314:20)
    at maybeClose (internal/child_process.js:1022:16)
    at Socket.<anonymous> (internal/child_process.js:444:11)
    at Socket.emit (events.js:314:20)
    at Pipe.<anonymous> (net.js:675:12) {
  killed: false,
  code: 1,
  signal: null,
  cmd: 'stty size'
}

[Alhadis]

Try this:

const childProcess = require("child_process");

const {stdout: tty} = childProcess.spawnSync("tty", {
	stdio: ["inherit", "pipe", "inherit"],
	encoding: "utf8",
});

childProcess.execFile("stty", ["-f", tty.trim(), "size"], (error, stdout) => {
	console.log(error || stdout);
});

However, it's much easier to use the getters that Node.js provides natively:

const size =
	process.stdout.isTTY ? [process.stdout.columns, process.stdout.rows] :
	process.stderr.isTTY ? [process.stderr.columns, process.stderr.rows] :
	process.stdin.isTTY  ? [process.stdin.columns,  process.stdin.rows]  :
	null;

[sindresorhus]

1. It cannot use inherit as that could potentially output stuff directly to the users terminal, and a reusable package should not do that.
2. It has to work even if the code spawning stty is spawned itself. Meaning multiple levels of spawning.
3. process.stdout.columns is undefined if it's in a spawned file.

---

The point of this binary is to get the columns and rows no matter what.

[Alhadis]

It cannot use inherit as that could potentially output stuff directly to the users terminal

Not if you're inheriting only the standard input stream:

 const {stdout: tty} = childProcess.spawnSync("tty", {
-	stdio: ["inherit", "pipe", "inherit"],
+	stdio: ["inherit", "pipe", "pipe"],
 	encoding: "utf8",
 });

The stdio array pertains to STDIN, STDOUT, and STDERR, respectively.

[sindresorhus]

Closing as this is no longer used by term-size: https://github.com/sindresorhus/terminal-size/releases/tag/v4.0.0