Using curl to test port connectivity

It's often necessary to troubleshoot port connectivity as common env, but not found telnet.

curl -v telnet://target ip address:desired port number

curl -v telnet://dragon1:22
* Rebuilt URL to: telnet://dragon1:22/
* Trying
* Connected to dragon1 ( port 22 (#0)


Generate Cron Expression in SOP

Sometimes, the cron expression is difficult to generate while you want to resolve urgent things. Let us SOP to generate cron expression.

Here are two links to easily generate cron expression.

  1. http://www.cronmaker.com/
  2. Cron Expression Generator & Explainer - Quartz


Building Software

Based on Kent Beck describes three activities in building software:

  1. First make it work. (make business or money first)
  2. Then make it right. (refactor code ...you and others can understand it as needs change)
  3. Then make it fast. (refactor code for "needed" performance, don't do this first)