FD(4) BSD Programmer's Manual FD(4) NNAAMMEE ffdd, ssttddiinn, ssttddoouutt, ssttddeerrrr - file descriptor files DDEESSCCRRIIPPTTIIOONN The files _/_d_e_v_/_f_d_/_0 through _/_d_e_v_/_f_d_/_# refer to file descriptors which can be accessed through the file system. If the file descriptor is open and the mode the file is being opened with is a subset of the mode of the ex- isting descriptor, the call: fd = open("/dev/fd/0", mode); and the call: fd = fcntl(0, F_DUPFD, 0); are equivalent. Opening the files _/_d_e_v_/_s_t_d_i_n, _/_d_e_v_/_s_t_d_o_u_t and _/_d_e_v_/_s_t_d_e_r_r is equivalent to the following calls: fd = fcntl(STDIN_FILENO, F_DUPFD, 0); fd = fcntl(STDOUT_FILENO, F_DUPFD, 0); fd = fcntl(STDERR_FILENO, F_DUPFD, 0); Flags to the open(2) call other than O_RDONLY, O_WRONLY and O_RDWR are ignored. FFIILLEESS /dev/fd/# /dev/stdin /dev/stdout /dev/stderr SSEEEE AALLSSOO tty(4) 4.4BSD June 9, 1993 1