Deep Reflections

This post shows you how to rotate old logs from your application. There is no change to application code. There is no specialized logging library or framework needed. It works for any language, on standard Unix platform.

Can you quickly close a TCP connection in your program by sending a reset (“RST”) packet?

This is a story of a program that worked, until it broke on a 64-bit platform.

It is true. Even on the latest FreeBSD 11.0 (I checked the source tree).

I use Emacs (emerge) while merging files. Today, when trying to merge some Python code, I found that it was taking exceedingly long time. It was blank for 5 minutes and counting.

This is a story of multiple processes running on a system, but with empty PID files.

It took a lot of debugging.

Can you tell me when a shell sends a “HANGUP” signal to a process? What happens if there is a pipeline? What if you prefix this pipeline with the “nohup” command?

If you don’t do log rotation right, you may have a full hard drive and a ghost file.

Have you run into a problem that happens only once in a while, and you never seem to have enough information to figure it out? We all have. This is one such tale: except that it has a happier ending.

As programmers, we face it many times: a build fails on only our system. This is one such tale.