8.1. Startup
If the Bourne shell is your login shell, it follows a chain of processes before you see a shell prompt.
Figure 8.1. Starting the Bourne shell.
The first process to run is called init, PID 1. It gets instructions from a file called inittab (System V), or it spawns a getty process (BSD). These processes open up the terminal ports, providing a place where standard input comes from and a place where standard output and error go, and they put a login prompt on your screen. The /bin/login program is then executed. The login program prompts for a password, encrypts and verifies the password, sets up an initial environment, and starts up the ...
Get UNIX® Shells by Example, Third Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
