If my understanding is correct, pid files are used with daemons, that is when a program is run in the background.
The ampersand & seems to mean to request that the command is run in the background, see, for example here. The rsyslogd is started and controlled by init(8).
Writing a pid file, use the reserved name 'NONE' (all This option must be used if multiple instances of Specify an alternative pid file instead of the default The question came to live as a result of reading this line of code: /usr/sbin/rsyslogd -niNONE & I want to understand a little bit better, what a background process is.
