Question

I would like to write a script to check whethere the application is up or not using unix shell scripts.

From googling I found a script wget -O /dev/null -q http://mysite.com, But not sure how this works. Can someone please explain. It will be helpful for me.

Answer 1

1. Run the wget command
2. the -O option tells where to put the data that is retrieved
3. /dev/null is a special UNIX file that is always empty. In other words the data is discarded.
4. -q means quiet. Normally wget prints lots of info telling its progress in downloading the data so we turn that bit off.
5. http://mysite.com is the URL of the exact web page that you want to retrieve.

Many programmers create a special page for this purpose that is short, and contains status data. In that case, do not discard it but save it to a log file by replacing -O /dev/null with -a mysite.log.