Musings of ErisDS » Technology

An assortment of useful linux commands

ErisDS — Mon, 03 Oct 2011 17:35:13 +0000

This is a totally random post full of linux commands that I find useful but am always forgetting. I use linux at work and also on a command-line-only VM at home. I’m always battling with it, largely because I’m a noob. Usually after a couple of hours of playing with it I have a head full of really useful commands. However the next time I run into a problem I won’t remember any of them.

To prevent that happening again, this is a brain dump of all the commands I really, really should remember.

Installing stuff

You want to install something:

1 2	sudo apt-get update sudo apt-get install ####

Keeping things up-to-date:

1 2	sudo apt-get update sudo apt-get upgrade

It seems that a lot of the time aptitude is actually better at this stuff?

1	sudo aptitude full-upgrade

Cleaning up:

1 2	sudo apt-get autoclean sudo apt-get clean

(or use aptitude)

Something won’t install because you’ve not got access to it (it’s not available for your distro etc). You probably need to find a URL for a “PPA” from somewhere like http://launchpad.net (Try Googling “project-name ppa site:launchpad.net” – thanks @Keithamus) to add to:

1	sudo vim /etc/apt/sources.list

These usually require keys which are provided with the URL. To add the key:

1	sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys ###key###

There’s loads of useful information about this here: https://launchpad.net/+help/soyuz/ppa-sources-list.html

Where am I / it ?

What version of ubuntu am I on?

1	cat /etc/issue

Where is something installed (e.g. mysql)

1	which mysql

Where are the files located?

1	locate mysql

You probably want to pipe that into less

1	locate mysql \| less

To find a file with a specific file name the syntax is:

1	find PATH -name 'FILENAME'

An example might be:

1	find / -name 'myfile.txt'

To find text within a file the syntax is:

1	grep -r 'SEARCH' PATH

An example might be

1	grep -r 'Hello World' /

I always forget the -r to make it recursive and wonder why it doesn’t work.

Samba

Samba broke? Go Windows stylee & restart it:

1	sudo /etc/init.d/samba restart

Still broke? Get a more useful error message from Windows by going into the command prompt and typing

1	net use m: \\ip-address\service

(Yes OK this is a Windows command not a linux one…)

Perhaps it doesn’t recognise the username/password combo:

1	sudo smbpasswd –a username

(and enter a new password when prompted)

Still broke? You might need to do some reconfiguring in the config file. Remember to check that everything has the access privileges it needs

1	sudo /etc/samba/smb.conf

Noob

Yep, I are one! Like a linux redneck. I use a dash of trial and error mixed with a pinch of brute force, but normally I win in the end :D Hope someone else finds these useful. Also, yes I pretty much sudo everything. Sudo make me a sammich and all that jazz.
See something really bad here? Please enlighten me, but be gentle!

Today I learnt Git…

ErisDS — Tue, 28 Dec 2010 23:54:57 +0000

I’ve been working with SVN for a couple of years. I’m familiar with it now, it no longer seems like a militant policing system that enforces rules on my way of working, and instead feels like a reliable old friend who looks out for me when I inevitably cock something up. SVN is pretty cool.

Getting comfortable makes me antsy. Being familiar with one tool, and one tool only for a particular job, is in my mind, a very bad habit. It’s a bad habit because that’s what these things become – I use them out of habit, not because they are good, or the right tool for the job, but because it’s what I know, and like and am comfortable with. My comfort zone makes me uncomfortable.

I’ve been toying with Git for a while now. I’ve had it installed on my computer, I’ve read about it, I’ve got an account on GitHub and I’ve even forked a few things (tee hee). But today I’ve gotten serious. I’ve decided to manage my next few personal projects with Git instead of SVN, and try to add it as another tool in my personal web armoury.

Getting Git

“My comfort zone makes me uncomfortable.”

First things first, I’ve just installed it on my Ubuntu Virtual Machine. Linux is something I’ve been working with for a long time, but never really gotten comfortable with or particularly used to… another reason to invest some time setting up Git, as very soon I will be working pretty exclusively with Linux (but that’s another story).

With Git installed, I could use a local repository for my projects, but that seems kinda pointless – sure if I stuff up a change, I can go back to an earlier version, but if I corrupt my VM then what? I could also use my account on GitHub, but as it’s just some testing/playgrounds, it seems odd to make it public. Instead I’ve decided to use my lovely Unfuddle account. Unfuddle lets me create fully backed up SVN and/or Git repositories on a free account, it’s pretty damn awesome!

Setting up a public key. Another one of those tasks that seems like it would be infinitely complicated, yet when you follow along with the documentation it suddenly becomes easy. Git mastery here I come.

My exploration into Git, GitHub and the underbelly of linux is all in aid of my desire to play around with the latest and greatest version of Symphony CMS – one of my favourite things the internet has to offer. So far I’ve managed to clone Symphony’s Git Repository from GitHub, setup my own Git repository on Unfuddle, and get my local project setup so that I can pull Symphony updates from one repository, and keep my own project-specific modifications in my own repository – meaning all the talk I’ve heard of Git having nothing to equal svn:externals is complete rubbish! Great :)

Final Git task.. make some custom modifications and save them back to my own repository. So I’ve “git committed” and spent ages wondering why my changes aren’t appearing in my private repository.. surely I can’t have committed to the Symphony repository – it’s read only? Only to discover that the whole point of Git of course, is that my commits are local, I have to “git push” them to the repository. Magic.

Well that’s the end of the beginning of my journey with Git. I feel like I’ve gotten the basics of how to do stuff, although the “why” and the underlying principles are still somewhat groggy. I’m sure it’ll make sense over time, and when I feel familiar I’ll post about the differences between SVN and Git and what each one is good/bad for.

G’Night.

Resources

A couple of things I’ve used to learn Git:

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How to view and extract Plesk backups

ErisDS — Tue, 19 Oct 2010 10:26:48 +0000

Have you ever had a minor developmental nightmare and needed quick access to a Plesk backup? Lost some data or needed a reference point and just wanted to get at a database’s SQL without having to do a full restore? Perhaps you’ve just wondered what a Plesk backup was & what is in it?

What is it?

Having worked exclusively with cPanel in the past, it was a bit of a shock to find that Plesk backups are not a simple gzipped dump of the files and database. Instead, Plesk uses a multi-part mime-encoded file which is usually also packaged in an archive. This makes it much harder to extract the various parts if you don’t want to do a full restore.

Getting inside

The first step to extracting a Plesk backup is to unzip it. I always use the windows utility 7zip as this can handle pretty much all forms of archive, and it doesn’t matter if the backup is zipped, tarred, or gzipped.

If small enough, the resulting file can be opened in your email client. Because mime is an email format, the multi-part mime-encoded file will be opened with the various parts as though they are attachments to an email. I tried with Mozilla Thunderbird and although it worked, it was very unstable and didn’t really provide a way to access the various parts/attachments.

Instead I use UUDeview which is a great tool for encoding and decoding mime and other binary files. Download and install the tool, then launch UUDeview. Click the “Add” button, and navigate to your newly extracted backup file. Next press preview and UUDeview will show you all the components of the backup which are available and which ones can be successfully decoded.

From the preview you can select and deselect the components you want to decode, and choose the path where you want the decoded files to be saved. Hit Go! and the magic happens :) I have found this generally works really well for extracting and decoding the mysql database dump. However, it doesn’t tend to do so well at extracting the files.

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Review: PC Line PCL-MH36 PC Headset – Cheap as Chips!

ErisDS — Thu, 16 Sep 2010 10:16:04 +0000

Since the start of ExplicitWeb I have been using this cheap-as-chips headset. It’s done me proud, so I thought they deserved a super quick review before I replace them.

Top marks for sound quality

The proof is in the pudding! Take a listen to one of the episodes (4, 6 and 8 are my current personal favourites) and you’ll find my voice is crisp and clear.

Could do better with comfort

This headset hurts. A real shame because all it needs is a bit of foam casing around the ear pieces. This is what killed the headset for me, my ears were always sore after recording an episode, or playing CoD:WAW for a while. Perhaps it’s just my ears though?

Conclusion

If you’re looking for something REALLY cheap and cheerful just to get you started with Skype or something and you either know you get on well with this style of earpiece or you don’t mind being a bit uncomfortable then I honestly doubt you’ll get better for a fiver… yes they’re just £5!!!

The Future

From Series 2, Episode 1 I will be using my all new headset: Creative HS800 Fatal1ty Gaming Headset, with detachable noise-cancelling microphone. I’ll write a review once we’ve done a few episodes with it :)

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What is WRONG with my iPhone?

ErisDS — Tue, 19 Jan 2010 08:05:04 +0000

Photo by Shht!

I’ve already filed a report on the Apple website & am about to go phone them for help. I’m not expecting much & I’m getting seriously frustrated. Maybe it’s only on Windows 7, but the iPhone syncing process seems to have some serious flaws.

I’ve had an iPhone for exactly a month today. In that time I have come to be totally addicted & completely in love with the device. It’s sleek, stylish, easy-to-use and does everything I need from the device in my pocket. But it’s also BUGGY, really, really BUGGY to the point where it’s almost useless.

Just after Christmas I made the mistake of syncing my phone on my work machine, such that everything was erased from the phone. Ok, silly mistake, but it shouldn’t be that easy to wipe your mobile phone! When I got home and tried to sync everything back – it wouldn’t.

Each time I attempted to sync it would throw 3 or 4 unintelligable errors messages and then iTunes would refuse to recognised my iPhone. I’d then have to do a restore & start over with the sync. Eventually I realised I could sync only by syncing 1 or 2 apps at a time – not the whole lot. Problem solved. No more accidental work syncing for me!

Last week I connected my phone up for a routine sync – I had some new music I wanted to get onto the phone for the weekend – but again it threw 3 or 4 unintelligable errors (like -48, -49 and -2ksomething) and failed to sync. Everything seemed ok with the iPhone, however halfway through my weekend away my apps started to do the “flash-and-crash” thing. This has happened before and turning the iPhone off and on again normally fixes it, but not this time! I read that some people had found installing a new app fixes it, so I tried that and luckily it worked.

Now I’m home and my iPhone isn’t recognised by iTunes anymore. I get a message saying “an iPhone has been previously synced with the machine” and allowing me to either set the iPhone up as a new phone, or restore from a really old backup. In addition, when using the iPod function it only plays one track and then crashes.

I’ve tried searching the net to see if others have this issue, and if there’s something I’m doing wrong. Maybe it’s Windows 7, maybe it’s cos I’m using Google Sync, or maybe there is some rogue app causing havoc during the syncing process. All I know is that losing all my data every 2 weeks is rendering my iPhone totally useless.

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