Background process

As background process is referred to in the computer science a process which does not act directly with the user, thus acting asynchronously to the user interface. The user action is usually carried out by auxiliary processes, especially applications that the user operates.

Background processes run asynchronously to the operating system shell. Modern Unix shells are able to start any process as a background process.

Background processes in Unix

On Unix and its derivatives, a process in a shell can be started in the background by calling an ampersand (&) is appended:

Cp -r / large / directory / target / directory & When such a call give modern shells mostly from the process ID of the started process. Use the kill command to the background process can be ended or possibly controlled by signals.

Typical programs that are designed to operate as a background process, are daemons.

When attempting to read data from the terminal, a background process is stopped by a signal. General background processes should not make use of terminal input.

The shell command bg leaves a process that was previously interrupted ( for example, Ctrl Z), running in the background. The command fg brings a background process to the foreground.

• Operating system theory
• Parallel processing