Wood's Words


Monitoring Java Memory Usage with Jstat and Check MK

02 Dec 2019

I recently wrote a script called check_jvm_memory to monitor JVM memory usage with jstat and Check MK. Let’s go over how to use it.


Process Substitution And Race Conditions

25 Nov 2019

In a recent article, I showed how to print a script’s output to both a log file and stdout. Some of you might be wondering why I used a { group command; } piped into tee for this, rather than >(process substition). Let me explain.


More Bash Patterns

23 Nov 2019

Let’s look at a few more patterns that a bash shell script can use. I’ll show how a script can drop its own privileges, run with a lower priority, obtain a lock file1, and create a temp file.

  1. I’ve removed the section about lock files after reddit user /u/vogelke raised some concerns about it. 


Bash Output Patterns

22 Nov 2019

Here’s a few patterns I use to send a bash script’s output to a log file, to syslog, or as an email notification.