xterm-256color: unknown terminal type
Trying to run `top` on an Ubuntu server from OSX Mountain Lion results in the following.
Thanks to Corentin Leclerc for the solution http://blog.corentinleclerc.com/terminal-sur-macos-x-lion-xterm-256color-unkn
Add the following to ~/.profile or ~/.bash_profile
1export TERM="xterm"
1export TERM="xterm"
Restart your terminal, or open a new tab. Magic.
1root@server:~# top 2 3top - 10:52:46 up 31 days, 16:34, 1 user, load average: 0.04, 0.02, 0.00 4Tasks: 57 total, 1 running, 56 sleeping, 0 stopped, 0 zombie 5Cpu(s): 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st 6Mem: 786652k total, 772360k used, 14292k free, 181920k buffers 7Swap: 0k total, 0k used, 0k free, 46000k cached 8 9 PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1026479 rails 20 0 89604 57m 2428 S 0.3 7.5 0:04.08 ruby1.8 11 1 root 20 0 1952 508 72 S 0.0 0.1 0:13.04 init 12 2 root 15 -5 0 0 0 S 0.0 0.0 0:00.12 kthreadd
Recover committed (deleted) file in Git
What if, just suppose, you deleted a file in error, made the commit to Git, then several commits later you realise you needed the file all along. How do you get it back?
Well, you find the last commit for that file and then checkout the file with the revision number. In just a few lines then…
Raspberry Pi - part 1
This year my main festive gift from the mighty Kat was a long awaited Raspberry Pi. Just never seemed to have the funds to nab one myself and I am pretty chuffed. If you’ve not heard of one then you’ve been living under a rock for the last year. The Raspberry Pi is basically just a very small, barebones computer. In fact its so minimal that it doesn’t even come with a case.

You can see on the board that the mounted interfaces are a dual USB port, micro-USB power supply, HDMI output to monitor, audio out, video out, GPIO pins.
You might have enough bits and bobs lurking in your cupboard full of cables and old hardware to get going but alas I do not. So in order to get started I need some way of hooking this up to a monitor, keyboard and powering the thing.
USB Keyboard
No PS2 ports so its all USB, so a USB Keyboard is needed. Relatively cheap, I’ve spotted a great wireless one with a touch pad for £25 but for now this one will do.
- CiT WK-738 Premium Mini USB Keyboard £6.25 from Amazon.
Monitor
While the Raspberry Pi can be easily used with a modern television I can’t see myself sitting in the front room while I’m playing with it for the time being. You can use any monitor or television with an HDMI or DVI connection. So you’ll need a cable
- 1.8M HDMI Cable for the Raspberry Pi £3.99 from ThePiHut
- HDMI to DVI Cable for the Raspberry Pi £5.99 from ThePiHut
My spare monitor is a VGA which won’t work without an adapter to convert the signal. £30 for an adapter is a bit much really. I’ve secured a DVI monitor from a friend for £10, so I’ve opted for the HDMI to DVI while I’m playing.
SD Card / Operating System
You’ll need an SD Card to install the operating system on. Fortunately we have an old 4Gb card from a Camera. So cost £0. Yay. average cost on Amazon about £6 so not bad.
Install it yourself
You can follow the tutorial on the Raspberry Pi Downloads page to copy an OS onto a card.
Pre-installed
You can get an 8Gb (and upwards) SD Card from ThePiHut with one of two distributions from £8.99.
- Raspbian – pre-installed Raspian is an optimised version of Debian, containing LXDE, Midori, development tools and example source code for multimedia functions.
- OpenElec / XBMC – pre-installed Open Embedded Linux Entertainment Center, or OpenELEC for short, is a small Linux distribution built from scratch as a platform to turn your computer into a complete XBMC media center.
That’s a start I’ve ordered what I need so now I have to sit and wait. I’ve got a few ideas about what I’d like to build.
- MAME centre
- Media centre
- Spotify streaming straight into the HiFi
So I’ll do a bit of research and buy a book or two.
Resources
There’s plenty of resources out there as well as some physical publications to get started with.
- Programming the Raspberry Pi: Getting Started with Python
- Getting Started with Raspberry Pi
- Raspberry Pi: A Quick-Start Guide
- Raspberry Pi User Guide
- Learn Raspberry Pi With Linux
More useful links…
Installing 'therubyracer' grrrr
1Robs-iMac:testapp rl$ gem install therubyracer 2Building native extensions. This could take a while... 3ERROR: Error installing therubyracer: 4 ERROR: Failed to build gem native extension. 5 6 /Users/rl/.rvm/rubies/ruby-1.8.7-p370/bin/ruby extconf.rb 7*** extconf.rb failed *** 8Could not create Makefile due to some reason, probably lack of 9necessary libraries and/or headers. Check the mkmf.log file for more 10details. You may need configuration options. 11 12Provided configuration options: 13 --with-opt-dir 14 --without-opt-dir 15 --with-opt-include 16 --without-opt-include=${opt-dir}/include 17 --with-opt-lib 18 --without-opt-lib=${opt-dir}/lib 19 --with-make-prog 20 --without-make-prog 21 --srcdir=. 22 --curdir 23 --ruby=/Users/rl/.rvm/rubies/ruby-1.8.7-p370/bin/ruby 24extconf.rb:13: uninitialized constant Gem (NameError) 25Checking for Python... 26 27Gem files will remain installed in /Users/rl/.rvm/gems/ruby-1.8.7-p370@thebevy/gems/libv8-3.3.10.4 for inspection. 28Results logged to /Users/rl/.rvm/gems/ruby-1.8.7-p370@thebevy/gems/libv8-3.3.10.4/ext/libv8/gem_make.out
It seems that libv8 requires Gem to exist, however rubygems is not available by default in Ruby 1.8.7. Ruby 1.9.x it is.
Thanks to Olly Smith for the solution
1Robs-iMac:thebevy rl$ RUBYOPT=-rrubygems gem install therubyracer 2Building native extensions. This could take a while... 3Fetching: therubyracer-0.10.2.gem (100%) 4Building native extensions. This could take a while... 5Successfully installed libv8-3.3.10.4 6Successfully installed therubyracer-0.10.2 72 gems installed 8Installing ri documentation for libv8-3.3.10.4... 9Installing ri documentation for therubyracer-0.10.2... 10Installing RDoc documentation for libv8-3.3.10.4... 11Installing RDoc documentation for therubyracer-0.10.2...
Apache Rewrite because I can never remember how to do it
I seem to use Apache less and less these days, so every year or so I have to try and remember the syntax for VirtualHost configs, redirects and the like.
1<VirtualHost *:80> 2 ServerName duncanwilkinson.com 3 DocumentRoot /home/duncan/www.duncanwilkinson.com/ 4 RackEnv production 5 RewriteEngine on 6 RewriteCond %{HTTP_HOST} !^duncanwilkinson\.com 7 RewriteRule ^/(.*)$ http://duncanwilkinson.com/$1 [R=permanent,L] 8 CustomLog /var/log/apache2/loathsome-access.log combined 9 ErrorLog /var/log/apache2/loathsome-error.log 10</VirtualHost> 11<VirtualHost *:80> 12 ServerName www.duncanwilkinson.com 13 ServerAlias www.dna-labs.net dna-labs.net www.triplebinary.com triplebinary.com www.needleye.net needleye.net 14 RewriteEngine on 15 RedirectMatch (.*) http://duncanwilkinson.com 16</VirtualHost> 17<VirtualHost *:80> 18 ServerName www.collapse.co 19 ServerAlias collapse.co 20 DocumentRoot /home/duncan/www.collapse.co/ 21</VirtualHost>
iptables reminder
Forgot all about iptables….
1rails # iptables -A INPUT -s <naughty ip> -j DROP 2 rails # iptables --list 3Chain INPUT (policy ACCEPT) 4target prot opt source destination 5DROP all -- bl16-108-238.dsl.telepac.pt anywhere 6 7Chain FORWARD (policy ACCEPT) 8target prot opt source destination 9 10Chain OUTPUT (policy ACCEPT) 11target prot opt source destination
Resize multiple images in one bash script
Badoom……!!!
Delete files created more than 14 days ago
When you’ve got lots of temporary files on a unix server and you never clean them out this might help. Remove files that were created more than 14 days ago like so…
1find . -type f -mtime +14 -exec rm {} \;
doing away with www.
“www.” for the most part is a pointless idea. We all know what a web page is. The “www.” prefix is outdated although necessary evil. I guess the same could be said of http:// and https:// for web requests …we all know what it means.
Here’s a quick snippet of my apache config to push all traffic from www.loathso.me to loathso.me
1<VirtualHost *> 2 ServerName www.loathso.me 3 ServerAlias loathso.me 4 DocumentRoot /var/www/loathsome/current/public/ 5 RackEnv production 6 RewriteEngine on 7 RewriteCond %{HTTP_HOST} ^www\.loathso\.me 8 RewriteRule ^/(.*)$ http://loathso.me/$1 [R=permanent,L] 9 CustomLog /var/log/apache2/loathsome-access.log common 10 ErrorLog /var/log/apache2/loathsome-error.log 11</VirtualHost>
Rails Serializers and INET_NTOA
MySQL doesn’t have a built in type for an IP Address, PostgreSQL does though. You’ll find that ip addresses are often stored as an integer. You can translate between an integer and ip address and vice versa with a built in MySQL functions. In a recent piece of work we had to detect a user’s country code based on their incoming IP via against a range of IPs (stored as integers).
1mysql> SELECT INET_ATON('192.168.0.1'); 2+--------------------------+ 3| INET_ATON('192.168.0.1') | 4+--------------------------+ 5| 3232235521 | 6+--------------------------+ 71 row in set (0.00 sec) 8 9mysql> SELECT INET_NTOA('3232235521'); 10+-------------------------+ 11| INET_NTOA('3232235521') | 12+-------------------------+ 13| 192.168.0.1 | 14+-------------------------+ 151 row in set (0.00 sec)
Wouldn’t it be nice to get a Rails model to accept an ip address and store it as an integer. Well its basically serializing the ip address and using Rails 3.1’s new serialization api we can do the following.
Basicially a class with two methods IpEncoder#load encodes its input, and IpEncoder#dump decodes it. Then you simply add the following to your model.
And there you have it.