Bash Functions

This post contains few functions, or tips I often use, so I keep them close.

Elasticsearch: setting up watcher for FS monitoring

In this post, we'll go through components used for this case scenario and the process of setting up a watcher within elasticsearch.

Our case scenario: we have three machines running different OS (all are linux based) and we'd like to be notified when we're running low on disk space. For this we've taken advantage of running elasticsearch instance with Gold license and enabled watcher feature.

SF OS X

Android. That's the operating system which most probably runs on your mobile phone.
While this is the very common system to have nowadays, it's matured enough throughout the years and built very rich ecosystem of applications, there are a few things which I don't like on it.

The basic idea is, that if you buy something, you should own it. You should be able to disassemble it and modify it, to adjust it to your needs and most noticeably: you should be in full control of your device.

Hide Tab Bar in Firefox 57+

Finally I've found a way to hide tabs from Firefox.
I use Tree Style Tabs addons and don't need native tabs.

So here is how you can do it:

Ping-based Host Monitoring Script with Timestamps

In my previous post Server availability monitoring with email notifications I've used the same idea of monitoring. This script is a version 2.0 with some additional features:

1. If you compare old and new version, you'll notice the script was completely rewritten. It's because I wanted it to run on my synology NAS.
2. Next change is additional host states, instead of A-available and N-notAvailable I'm now using 2 additional states Going Up, Going Down. This will delay the notification about host state change and prevent frequent flapping of naughty hosts in network.
3. Last feature added is hosts UP/DOWN times in notifications; see mail notification example:

SSH Two Factor Authentication for RaspberryPi

Another cool feature for your remote ssh connection - 2-factor authentication or 2-step verification. It helps to improve security for remote access to your machine and it is pretty simple to setup, you can get it up and running in just a few minutes...

autofs: automount nfs share

This small tool is designed to mount various types of filesystems, not only NFS shares. It watches for when you try to access defined mount point and auto-mount it right away. Then after specified timeout, it will unmount them.
Advantage: if you have many NFS clients, you may want to reduce active connections to the server and improve overall performance of the server. Or perhaps you are too lazy to mount NFS, as I am and just give it to the hands of autofs (: