quartz/content/notes/10-scheduled-tasks-and-logs.md

title	tags
10-scheduled-tasks-and-logs	lecture cosc301

Daemon

• A process that runs in the background and is independent of control from all terminals
• Reasons for daemons’ independence of terminals
  • Prevent daemons’ error message from appearing on a user’s terminal
  • Signals generated from terminal keys must not affect any daemons that were started from that terminal earlier
• Typical daemons
  • crond, syslogd

Daemonization

if( (pid = fork()) != 0) exit(0); //parent terminates 
setsid(); // become session leader 
signal(SIGHUP, SIG_IGN); if( (pid = fork()) != 0) exit(0); //new child continues 
//now it becomes daemon

The purpose is to make the process independent of the control from any terminals.

[!INFO] when you are independent from

Scheduled tasks

• Automating tasks
  • crond and crontab
  • crond is a very important daemon for automatically executing tasks
  • Tasks can be configured to repeat hourly, daily, weekly,…, or even per minute.
• Possible uses
  • Clean file systems
  • Log rotate
  • Check log files
  • Monitor system status and resources