File descriptors

File descriptors

􀁺 Each UNIX process has 20 file descriptors at it
disposal, numbered 0 through 19.
􀁺 The first three are already opened when the process
begins
􀁺 0: The standard input
􀁺 1: The standard output
􀁺 2: The standard error output
􀁺 When the parent process forks a process, the child
process inherits the file descriptors of the parent.