/dev/fd/ is a symlink to /proc/self/fd. The files under /proc/self/fd are (always or likely?) symlinks also: $ ls -l /dev/fd lrwxrwxrwx 1 root root 13 Feb 3 2024 /dev/fd -> /proc/self/fd $ ls -l /proc/self/fd/* ls: cannot access '/proc/self/fd/255': No such file or directory ls: cannot access '/proc/self/fd/3': No such file or directory lrwx------ 1 rene rene 64 Feb 3 16:42 /proc/self/fd/0 -> /dev/pts/2 lrwx------ 1 rene rene 64 Feb 3 16:42 /proc/self/fd/1 -> /dev/pts/2 lrwx------ 1 rene rene 64 Feb 3 16:42 /proc/self/fd/2 -> /dev/pts/2