This preview shows page 1. Sign up to view the full content.
Unformatted text preview: ne typed by the user consists of a name and zero or more arguments, all separated by one or more spaces. If name is a built-in command, the shell handles it immediately and waits for the next command line. Otherwise, the shell assumes that name is an executable ﬁle, which it loads and runs in the context of an initial child process (job). The process group ID for the job is identical to the PID of the child. Each job is identiﬁed by either a process ID (PID) or a job ID (JID), which is a small arbitrary positive integer assigned by the shell. JIDs are denoted on the command line by the preﬁx ’%’. For example, “%5” denotes JID 5, and “5” denotes PID 5. If the command line ends with an ampersand, then the shell runs the job in the background. Otherwise, the shell runs the job in the foreground. Typing ctrl-c (ctrl-z) causes the shell to send a SIGINT (SIGTSTP) signal to every process in the foreground process group. The jobs built-in command lists all background jobs. The bg <job> built-in command restarts <job> by s...
View Full Document
- Spring '10
- The American