Recent Comments


Valid XHTML 1.0 Transitional

Systemd Notes

A few months ago I gave a lecture about systemd for the Linux Users of Victoria. Here are some of my notes reformatted as a blog post:

Scripts in /etc/init.d can still be used, they work the same way as they do under sysvinit for the user. You type the same commands to start and […]

Inteltech/Clicksend SMS Script

USER=username API_KEY=1234ABC OUTPUTDIR=/var/spool/sms LOG_SERVICE=local1

I’ve just written the below script to send SMS via the service. It takes the above configuration in /etc/sms-pass.cfg where the username is assigned with the clicksend web page and the API key is a long hex string that clicksend provides as a password. The LOG_SERVICE is which syslog service […]

Modern Swap Use

A while ago I wrote a blog post debunking the idea that swap should be twice as large as RAM [1]. The issue of swap size has come up for discussion in a mailing list so it seems that it’s worth another blog post.

Swap Size

In my previous post I suggested making swap space […]


I’ve just installed BTRFS on some systems that matter to me. It is still regarded as experimental but Oracle supports it with their kernel so it can’t be too bad – and it’s almost guaranteed that anything other than BTRFS or ZFS will lose data if you run as many systems as I do. Also […]

Parsing Daemontools/Multilog dates in Shell Script

I run some servers that use the DJB Daemontools to manage their daemons [1]. This is something I would have changed years ago if given a chance because DJB software always seems to do things in a different way to other Unix software and causes pain. Unfortunately when you have a lot of semi-embedded systems […]

Maintaining Screen Output

In my post about getting started with KVM I noted the fact that I had problems keeping screen output after the program exits [1].

The following snippet of shell code demonstrates the solution I’ve discovered for this problem. It determines whether SCREEN is the parent process of the shell script and if so it sleeps […]

SCO Unix and Proftpd

I recently had the misfortune to be compelled to install Proftpd on SCO Unix. There’s nothing wrong with Proftpd of course, but everything is wrong with SCO.

LDFLAGS=-L/usr/ucblib ./configure –libdir=/usr/ucblib --enable-builtin-getnameinfo

To get it to compile the above ./configure line is needed. It uses /usr/ucblib because having the basic BSD sockets API residing in a […]

Some Tips for Shell Code that Won’t Destroy Your OS

When writing a shell script you need to take some care to ensure that it won’t run amok. Extra care is needed for shell scripts that run as root, firstly because of the obvious potential for random destruction, and secondly because of the potential for interaction between accounts that can cause problems.

One possible first […]

Time Zones and Remote Servers

It’s widely regarded that the best practice is to set the time zone of a server to UTC if people are going to be doing sys-admin work from various countries. I’m currently running some RHEL4 servers that are set to Los Angeles time. So I have to convert the time from Melbourne time to UTC […]

The Date Command and Seconds Since 1970-01-01

The man page for the date command says that the %s option will give “seconds since 1970-01-01 00:00:00 UTC“. I had expected that everything that date did would give output in my time zone unless I requested otherwise.. But it seems that in this case the result is in UTC, and the same seems to […]