Tag: bash

THIS. CHANGES. EVERYTHING. – Useful Bash/*nix Tricks I Never Stumbled Across in the Last 15 Years

A thread at /r/linux sought out to reveal all the magic ways of increasing productivity under Linux (or other *nix based OS-es), and as most people I thought that there wouldn’t be much news here.

But I was wrong. So very, very wrong.

  1. disown – a way to disown a process, making it continue running in the background if you have to log out or close a long running session over ssh because you’re going somewhere, but want to keep the currently running process still running. If you’ve ever thought “why the fsck didn’t I run this under screen?”, then this trick is for you. This is a new future, and I’m proud to be a part of it.
  2. CTRL+r in bash – allows you to search your bash history buffer. I’ve known about this, I’ve just never picked up the habit of actually using it. Will do that now.
  3. ssh-copy-id – Appends your public key to the authorized_keys file at the destination computer.
  4. man ascii – the manual page entry for ascii contains an ascii table, right there in your terminal.
  5. xargs ‐‐max-procs and parallel – allows you to duplicate the functionality of xargs, but in parallel. Starts up all the processes at the same time, instead of starting them one by one.

Head over to the thread for other goodies such as a sudo alias for writing files when you’ve opened them without the correct permissions directly in vim.

Writing a Munin Plugin

I have to admit something. I’ve become addicted.

One of the things I finally got around to doing while living the quiet life over the christmas holiday was to dive a bit further into Munin – a simple framework for collecting information from your computers and servers and making nice graphs that you can watch while you’re bored.

I’m not going to write a lot about how you can create your own Munin plugin to create your own graphs, as they have a very simple tutorial giving you all the basics about writing Munin plugins themselves. The only thing you need to remember are these two tidbits:

  1. When Munin first registers your plugin, it runs your script with config as the only argument. This provides Munin with the name of the graph, the labels and names (keys) of the graphs you’re providing values for, information about the axis, etc.
  2. When Munin runs your script without the config argument, it expects you to give it values for the keys you provided it in the configuration.

You enable and disable plugins by creating symlinks in /etc/munin/plugins (at least under debian / ubuntu), and plugins are usually stored in /usr/share/munin/plugins.

I keep my plugins archived together with the rest of the repository for my web projects, and then either symlink the content into the plugins-directory or create a simple wrapper script that changes the current directory to the location of the script and then invokes it (to make the current working directory be correct).

A very simple bash script that does this – and passes through any parameters given to the script:

#!/bin/bash
cd  && php ./