Describe the bug

Interactive applications such as text editors are not able to open files when spreading $in, such as ls file.txt | get name | vi ...$in.

How to reproduce

All these cases assume file.txt exists.

Vim

1. Run ls file.txt | get name | vi ...$in
2. The following error is printed:

Vim: Warning: Input is not from a terminal
Vim: Error reading input, exiting...
Vim: Finished.

3. Vim crashes.

mg

1. Run ls file.txt | get name | mg ...$in
2. The error "panic: standard input and output must be a terminal" is printed
3. mg crashes.

In the case of mg, the code panics at ttyio.c:ttopen() after failed isatty(3) calls:

/*
 * This function gets called once, to set up the terminal.
 * On systems w/o TCSASOFT we turn off off flow control,
 * which isn't really the right thing to do.
 */
void
ttopen(void)
{
	if (!isatty(STDIN_FILENO) || !isatty(STDOUT_FILENO))
		panic("standard input and output must be a terminal"); // here

	if (ttraw() == FALSE)
		panic("aborting due to terminal initialize failure");
}

Expected behavior

In Nushell, ls file.txt | get name | mg ...$in should:

• ✅ be equivalent to realpath file.txt | xargs -o mg in Bash
• ❌ not be equivalent to realpath file.txt | xargs mg in Bash

This is a known issue with xargs; it points stdin to /dev/null while Vim expects its stdin to be the same as its controlling terminal. This issue can be mitigated by using xargs -o instead:

Reopen stdin as /dev/tty in the child process before executing the command. This is useful if you want xargs to run an interactive application.

This use case should also be updated in the documentation.

Configuration