$ ls -al /dev/std* lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stderr -> fd/2 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdin -> fd/0 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdout -> fd/1 $ ls -n /dev/fd/[012] crw--w---- 1 501 4 0x10000000 Feb 27 13:38 /dev/fd/0 crw--w---- 1 501 4 0x10000000 Feb 27 13:38 /dev/fd/1 crw--w---- 1 501 4 0x10000000 Feb 27 13:38 /dev/fd/2 $ uname -v Darwin Kernel Version 24.6.0: Mon Jan 19 22:00:55 PST 2026; root:xnu-11417.140.69.708.3~1/RELEASE_ARM64_T6000 $ sw_vers ProductName: macOS ProductVersion: 15.7.4 BuildVersion: 24G517
$ zsh -c 'ls -al /dev/std*' lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stderr -> fd/2 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdin -> fd/0 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdout -> fd/1 $ csh -c 'ls -al /dev/std*' lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stderr -> fd/2 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdin -> fd/0 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdout -> fd/1 $ tcsh -c 'ls -al /dev/std*' lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stderr -> fd/2 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdin -> fd/0 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdout -> fd/1 $ ksh -c 'ls -al /dev/std*' lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stderr -> fd/2 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdin -> fd/0 lr-xr-xr-x 1 root wheel 0 Feb 24 15:08 /dev/stdout -> fd/1