Maximum of 9 file descriptors

Maximum of 9 file descriptors

[JD Ballard]

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Is there a reason why file descriptors are maxed out at 9?

    $ zsh
    $ cat 9>/tmp/foo # works
    $ cat 10>/tmp/foo # error

With Bash, this isn't the case.

    $ bash
    $ cat 9>/tmp/foo # works
    $ cat 10>/tmp/foo # also works

Re: Maximum of 9 file descriptors

[Bart Schaefer]

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On Thu, Jul 23, 2015 at 10:47 AM, JD Ballard <i.am.qix@gmail.com> wrote:
> Is there a reason why file descriptors are maxed out at 9?

It's not a descriptor limitation, it's a syntax limitation. The syntax for
">" permits only a single digit to the left.

You can work around it this way:

$ fd=10
$ cat {fd}>/tmp/foo

Although FDs 10,11,12 tend to be used a lot by the shell internally.

Re: Maximum of 9 file descriptors

[Vincent Lefevre]

On 2015-07-23 17:47:36 +0000, JD Ballard wrote:
> Is there a reason why file descriptors are maxed out at 9?

FYI, I started a discussion "multi-digit file descriptors"
a few months ago:

  http://www.zsh.org/mla/users/2015/msg00211.html

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