Читать книгу Linux Bible - Christopher Negus - Страница 106

Some commands can take a while to complete. Sometimes, you may not want to tie up your shell waiting for a command to finish. In those cases, you can have the commands run in the background by using the ampersand (&).

Text formatting commands (such as nroff and troff, described earlier) are examples of commands that can be run in the background to format a large document. You also might want to create your own shell scripts that run in the background to check continuously for certain events to occur, such as the hard disk filling up or particular users logging in.

The following is an example of a command being run in the background:

 $ troff -me verylargedocument | lpr &

Don't close the shell until the process is completed or that kills the process. Other ways to manage background and foreground processes are described in Chapter 6, “Managing Running Processes.”