Shell Tips !

I use math in bash scripts a lot, from simple crontab reports to Nagios monitoring plugins… Here is few small examples on how to do some maths in Bash with integers or float.

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With Ganglia, graphing a large number of servers has never been so easy… Ganglia is a scalable distributed monitoring system for high-performance computing systems such as clusters and Grids. Ganglia let you create any kind of module in C/C++ or Python. You can also use the command line tool Gmetric and then the scripting language of your choice. The problem with Gmetrics is that you can’t keep your data organized by group and it’s getting harder to poll values in an efficient way. Few months ago I needed to monitor some JMX values returned by a Java daemon.

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The “Security sandbox violation” message is a common problem for any Flash developer who try to do a Snapshot of an RTMP Stream. There was a couple of workaround but they stopped working since Flash Player 9.0.115 as it was considered as a possible bug. So, now how to do a proper snapshot of an RTMP stream ? The answer is simple but you’ll need to have the control on the streaming server, whatever it is FMS or Red5.
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