What Hardware Do I Have?

There are many cases where you may not necessarily know what kind of hardware you have. You may have bought a no-name box from a smaller company. Or you may have bought a used machine. In any case you may not know what you have for hardware. This month we'll look at tools you can use to find out what you have installed.

The first tool to look at is lshw. This utility LiSts HardWare (lshw). If you run it as a regular user it will actually warn you to run it as root. So go ahead and run "sudo lshw". You should now see screens of information for your system. The first section will be general information, and should look something like

jbernard-eeepc
description: Notebook
product: 700
vendor: ASUSTeK Computer INC.
version: 0129
serial: EeePC-1234567890
width: 32 bits
capabilities: smbios-2.5 dmi-2.5 smp-1.4 smp
configuration: boot=normal chassis=notebook cpus=1 uuid=XXXXXX-XXXXX-XXXXX-XXXXX

This is what I get when I run it on my little Asus EeePC. So right away we can find out the manufacturer of this little beast (ASUSTeK), the BIOS version (0129), and the fact that it is a 32-bit machine with one CPU. There is more information broken down into the following categories

core
firmware - motherboard and BIOS information
cpu - CPU information
cache - cache information
memory - memory information
bank - specific bank memory information
pci - PCI bus information
display - PCI diplay adapter
multimedia - PCI audio adapter
pci - other PCI devices
network - PCI network adapter
usb - USB devices
ide - IDE information
disk - individual disks
volume - volumes on this disk

If we look at the section describing main memory, we get on my EeePC

*-memory
description: System Memory
physical id: 1f
slot: System board or motherboard
size: 512MiB
*-bank
description: DIMM DDR2 Synchronous 400 MHz (2.5 ns)
product: PartNum0
vendor: Manufacturer0
physical id: 0
serial: SerNum0
slot: DIMM0
size: 512MiB
width: 64 bits
clock: 400MHz (2.5ns)

we can get an idea of how much information is available.

This utility is kind of an all in one tool that spits out everything on your system in one go. But what if you want information only about specific subsystems in your machine. There is an entire suite of utilities you can use for this. These might be more useful when you want some specific piece of information, or you want to do some system querying in a script.

The first thing you may want to look at is the CPU. The utility lscpu will give you output similar to

Architecture: i686
CPU op-mode(s): 32-bit
CPU(s): 1
Thread(s) per core: 1
Core(s) per socket: 1
CPU socket(s): 1
Vendor ID: GenuineIntel
CPU family: 6
Model: 13
Stepping: 8
CPU MHz: 571.427

From this, you can find out the manufacturer, whether it is 32-bit or 64-bit, the exact version and model, as well as the current CPU frequency.

If you want to find out whether your video card is supported by X11, or whether you'll need to go and find a third-party driver, you can use lspci. This utility will give you a list of all of the devices plugged into you PCI bus. The output will look something like

00:02.0 VGA compatible controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 04)
00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller (rev 04)

With this information we can see that the video controller in my EeePC is an Intel controller. So, if you wanted to, you could now hit Google with this information to learn about your video card and how best to configure it. If you want to see what USB devices are on your system, you can use lsusb. On my EeePC I have an SD card installed, and it shows up as

Bus 001 Device 002: ID 0951:1606 Kingston Technology

The last piece of hardware we'll look at is the disk subsystem. You can find out what you have on your system with the utility blkid. This utility will print out all of the filesystems available to you, with an output format of

/dev/sda1: UUID="XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX" TYPE="ext2"
/dev/sda2: UUID="XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX" TYPE="swap"
/dev/sda3: UUID="XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX" TYPE="ext2"
/dev/sdb1: UUID="XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX" TYPE="ext2"

With this utility, you can find out what devices are available and what filesystems are being used on them. The associated UUID's are also available, in case you want to use them in the entries in /etc/fstab.

Now that we know what kind of hardware we have on our system, the last thig to check is to see if our kernel is actually using this available hardware. On most modern distributions, the kernel is compiled to use modules. You can check to see which modules are loaded by using the command lsmod. We get a list that looks like

agpgart 31788 2 drm,intel_agp
lp 7028 0
video 17375 1 i915
output 1871 1 video

We can see that the agpgart modules has a size of 31788 bytes, and is used by the drm and intel_agp modules.

Now that you know what you have installed for hardware, you can hopefully get it all configured and optimized so that you get the most out of it. If you find other utilites that aren't covered here, I would love to hear about them.

How To Write Unmaintainable Code

How To Write Unmaintainable Code: All programmers who want to guarantee job security really should read this.

'via Blog this'

The Web on the Console

Most people think graphical interfaces when they think of surfing the web. And under X11, there are lots of great programs, like firefox or chrome. But, the console isn't the wasteland that it might seem. There are lots of utilities available to surf the web, and also to download content from or upload content to the web.

The first thing you may want to do is surf around the web and find some content. The first utility to look at is also one of the oldest, the venerable lynx. Lynx was actually my first web browser, running on a machine that couldn't handle X11. Using it in its most basic form, you simply run it on the command line and give it a file name or a URL. So, if you wanted to hit Google, you would run
lynx http://www.google.com
The first thing you will notice is that lynx will ask you whether you want to accept a cookie that Google is trying to set. Once you either accept or reject the cookie, lynx will load the web page and render it. As you will no doubt notice, there are no images. But all of the links and the text box for entering your search query are all there. You can simply navigate around from link to link with your arrow keys. Because the layout is very simple and text-based, items will be in very different locations on the screen from what you will see using a graphical browser.

There are several options to lynx that might be handy to know. The first useful tip is that you can hand in more than one URL when you launch lynx. Lynx will add all of these URLs to the history of your session and render the last URL and display it. When you tested loading Google above, lynx asked you about whether or not to accept a cookie. Most sites these days use cookies. You may not want to hear about every cookie. You can use the option "-accept_all_cookies" to avoid all of these warning messages. You can use lynx to process web pages into a readable form by using the option "-dump". This will take the rendered output from lynx and write it out to standard out. This way you can simply process web pages to a readable format and dump them into a file for later viewing. You can choose what kind of key mapping you wish to use by using the options "-vikeys" or "-emacskeys". By using one of the options, you can use shortcut keys that match your editor of choice.

Lynx does have a few issues. It has a hard time with HTML table rendering and doesn't handle frames. Along comes the browser links. Links not only works in text mode on the command line, but can also be compiled to use a graphics display. The graphics systems supported include X11, svga, and framebuffer. You can select one of these graphics interfaces with the option "-g". Links can also write out the rendered web pages to standard output by using the option "-dump". If you need to use a proxy, you can tell links which to use with the option "-http-proxy host:port". Links is also able to deal with buggy web servers. There are several web servers out there which claim to be compliant to a particular HTTP version and aren't. To try and compensate for this, you can use the "-http-bugs.*" options. For example, "-http-bugs.http10 1" forces links to use HTTP 1.0, even when a server claims to support HTTP 1.1.

If you are looking for a strictly text replacement for the venerable lynx, there is elinks. Elinks supports colors, table rendering, frames, background downloading and tabbed browsing. One possibly useful option is "-anonymous 1". This option disables local file browsing and downloads, among other things. Another interesting option is "-lookup". When you use this, elinks will print out all of the resolved IP addresses for a given domain name.

Now that we can look at web content from the command line, how can we interact with the web? What I really mean is, how do we upload and download from the web? There are many instances where you may want an offline copy of some content from the web that you can read through at your leisure, off by the lake where you don't have any Internet access. One of the tools you can use to do this is curl. Curl can transfer data to or from a server on the Internet using HTTP, FTP, SFTP, even LDAP. It can do things like HTTP POST, SSL connections, and cookies. You can specify form name/value pairs so that the web server things you are submitting a form by using the option "-F name=value". One really interesting option is the ability to use multiple URLs through ranges. For example, you can specify multiple hosts with

curl http://site.{one,two,three}.com

which will hit all three sites. You can range through alphanumeric ranges with square brackets. The command

curl http://www.site.com/text[1-10].html

will download the files text1.html to text10.html.

But what if you want a copy of an entire site for offline browsing? The tool wget can help you out here. In this case, you will likely want to use the command

wget -k -r -p http://www.site.com

The option "-r" recurses through the links of the site starting at http://www.site.com/index.html. The option "-k" rewrites the downloaded files so that links from page to page are all relative so that you can navigate correctly through the downloaded pages. The option "-p" downloads all extra content on the page, such as images. This way you can get a mirror of a site on your desktop. Wget also handles proxies, cookies, HTTP authentication, along with many other conditions. If you're uploading content to the web, you can use wput. Wput pushing content up using ftp, with an interface like wget.

So now you should be able to interact with the Internet without ever having to use a graphical interface. Yet another reason to keep you on the command line.

Google Reader going away

Well, Google has announced that Reader is going away July 1. Argh! I was one of those who used almost religiously. Now I need to find a replacement. I think I have found it in Feedly. It seems to give me the same ability to keep multiple devices synchronized. The only think I haven't found yet is how to change the sort order so that I see the oldest articles at the top. Once I do, I think I'll be happy again.

Comparing Files

There are many times when you wish to know what has happened to a
file. You may be interested in comparing one version of a file to an
earlier one. Or you may need to check one file against a reference
file. Linux provides several tools for doing this, depending on how
deep a comparison you need to make.

The most common task involves comparing two text files. The tool of
choice for this task is diff. With diff, you can compare two files,
line by line. By default, diff will notice any differences between the
two text files, no matter how small. This could be as simple as a
space character being changed into a tab character from one file to
the next. The file will look the same to a user, but diff will find
that difference. The real power of diff comes from the options
available to ignore certain kinds of differences between files. In the
above example, you could ignore that change from a space character to
a tab character by using the option "-b" or
"--ignore-space-change". This option tells diff to ignore any
differences in the amount of whitespace from one file to the next. But
what about blank lines? The option "-B" or "--ignore-blank-lines"
tells diff to ignore any changes in the numbers of blank lines from
one file to the next. In this way, diff will effectively be only
looking at the actual characters and comparing them from one file to
the next. You have essentially narrowed the focus of diff to the
actual content.

What if that is not good enough for your situation? You may be
comparing files where one was entered with all capitals on, for some
reason. Maybe the terminal being used was misconfigured. In any case,
you may not want diff to report simple differences in case as "real"
differences. In this case, you can use the option "-i" or "--ignore-case".

What if you have files from a Windows box that you are working with?
Everyone who works on both Linux and Windows has run into the issue
with line endings on text files. Linux expects only a single newline
character while Windows uses a carriage return and a newline
character. diff can be told to ignore this with the option
"--strip-trailing-cr".

The output from diff can take a few different formats. The default
output contains the line which is different, along with a number of
lines just before and just after the line in question. These extra
lines are called context, and can be set with the option "-c", "-C" or
"--context=" and a number of lines to use for context. This default
output can be used by the program patch to change one file into the
other. In this way, you can create source code patches to upgrade code
from one version to the next. diff will also output differences
between files that can be used by ed as a script by using the option
"-e" or "--ed". diff will also output an RCS format diff by using the
option "-n" or "--rcs". The other option is to print out the
differences in two columns, side by side. The option "-y" or
"--side-by-side" will let you see each file side by side with the
differences between them highlighted.

The utility diff only compares two files. What if you need to compare
three files and see what changes exist moving from one to the others?
The utility diff3 comes to the rescue. This utility compares three
files and prints out the diff statements. Again, you can use the "-e"
option to print out a script suitable for the editor ed.

But what if you simply want to see two files and how they differ?
Another utility might be just what you are looking for, comm. With no
other options, comm takes two files and prints out three columns. The
first column contains lines unique to the first file, the second
column contains lines unique to the second file and the third column
contains lines common to both files. You can selectively suppress each
of these columns with the options "-1", "-2" and "-3". They suppress
columns 1, 2 or 3, respectively.

While this works great for text files, what if you need to compare two
binary files? You need some way to compare each and every byte in each
file. The utility that can be used for this is called cmp. It does a
byte by byte comparison of two files. The default output is a print
out of which byte and which line contains the difference. If you are
interested in seeing what the byte values are, you can use the option
"-b". The "-l" option gives even more detail, printing out the byte
count and the byte value from the two files.

Using these utilities, you can start to get a better handle on how
your files are changing. Here's hoping you keep control of you files.

SVN over SSH

There are many times when the only access to a server is over SSH. There are many reasons for this, including security. If you want to host an SVN repository on this machine, how do you access it? The first step is to create the repository. If you are creating a new one, then this easy.Just log in to the server and do the following

svnadmin create /path/to/repo

If you already have a repository that you want to move to the server, you should use svnsync to do so. First, you will want to allow a user to have svnsync access with

#!/bin/sh
USER=""
if [ "$USER" = "myusername" ]; then exit 0; fi
echo "Permission denied"
exit 1

This goes in the file /path/to/repo/hooks/pre-revprop-change. Make sure that it is set as executable

chmod +x ~/mymirror/hooks/pre-revprop-change

You can then tell svnsync to initialize the mirror.

svnsync init file:///path/to/repo
svn+ssh://username@svnmaster.domain.ext/newpath/to/repo

Once this initialization is done, you can sync the full data.

svnsync --non-interactive sync file:///path/to/repo

You can then interact with this new repository over SSH by using

ssh+svn://username@svnmaster.domain.ext/newpath/to/repo

as the connection details.

One problem that may come up when your SVN repository from one server to another is to fix up your local copy. There is a switch command that will allow you to do this.

svn switch --relocate old-url new-url

This way, you don't need to toss away your current working copy and checkout a fresh one.

Listening on the command line

On Linux, there are tons of programs you can use to listen to audio. Programs like totem, rhythmbox, mplayer, and vlc. One thing you may have noticed with each of these examples is that they all run in an X11 environment. What is a person to do if they want to listen to their favorite music on the command line? Well, let's take a look. Before we do, though, I want to stress that everything here will assume that you have a working audio subsystem on your machine. There is far too much variation in audio hardware to even begin to talk about how to setup audio on your machine.

Most distributions now use pulseaudio as the audio server. This provides a standard wrapper around the actual audio hardware. This way, software simply needs to talk to the pulseaudio server and won't need to worry about the messy details of how to talk to each sound card out there. The pulseaudio system also includes utilities that you can use on the command line.The most basic thing you will want to do is to play an audio file. To do this, you would use a command like

paplay --volume=32768 example.mp3

This will play the audio file example.mp3 at 50% volume (volume is set between 0, or silent, and 65536, or 100%). The utility paplay can play any audio format supported by the library libsndfile. So, you should be able to play most audio files you come across. If you don't have any audio files of your own, you can use the included utility parec. This program grabs raw audio data from your audio card's input, and dumps it to standard output. You can pipe this off to a file to save it for later. In order to play this raw data back, you can use the included utility pacat. It takes raw audio data and dumps it out to the audio card's output speaker.

What if you have a whole list of audio files you would like to listen to? There are several choices available to handle entire playlists of music for you from the command line. Two examples are cplay and moc. Both programs give you a file list on first starting up. From here, you can play individual files, or you can start constructing playlists to organize what audio files you are listening to. Both programs use shortcut keys to create, edit and otherwise manage your playlists. You can see the screenshots provided to get a feel for how they might look on your system.

Another audio task you might want to handle from the command line is to have your computer talk to you. Of course, once it can talk, it won't be long before it talks back. But anyway, there are several utilities available to give your computer a voice. These include recite, festival and espeak. The simplest is recite. It takes text in from standard input and outputs audio to the speakers. There aren't many options available. To speak a text file, you would simply execute

recite < example.txt

You can also simply execute recite, then start typing. Just remember that recite won't see the end of your typing until you hit ctl-D, to mark the end of input. It will then speak the entire text you just typed in. The program festival starts to provide more options. To get a basic output of text to audio, you would execute

festival --tts example.txt

You have the option of also using other languages. The default is English, but you can also use Spanish, Russian or welsh by using the command line option "--language ". Beyond this, festival also uses Scheme as a scripting language, which opens it up to a huge amount of modification. You'll need to spend some time reading the manual at http://www.cstr.ac.uk/projects/festival/manual/.

The last utility is espeak. Here you have several other command line options available. You can set the amplitude with "-a " (0 to 20, default is 10), the pitch with "-p " (0 to 99, default is 50) and speed with "-s " (in words per minute, default is 160). There are several voices available. You can find out which ones are installed on your system by using the command line option "--voices". Once you select one, use the command line option "-v " to use it. You then dump it out to a wave file by using the command line option "-w ". A full command line would look like

espeak -v en-scottish -w example.wav -f example.txt

Then you can play it using

paplay example.wav

Now your computer will speak in a Scottish accent, sort of. Speech synthesis is still not perfect.

Now that you have all of these audio files laying around, you may want to do some processing on them. One of the more useful tools to do this is sox. One utility included in the package is called soxi. It gives you file information about your audio files. In it's most basic form, you can use sox to change the file format of an audio file by simply running

sox example.wav example.au

sox is smart enough to use the file extensions to figure out that you are intending to convert the file example.wav (in wav format) to example.au (in the Sun au format). You can also do processing on the audio through command line options. The number of bits per sample to use can be set through "-b ". The number of channels to use can be set through "-c ". So, setting it to mono would be "-c 1", or stereo would be "-c 2". You can set the sample rate, in Hertz, through "-r ". There are also many options that apply filters to the audio files. Please go read the manual page to see just how much you can do with sox. One example command line you might use is

sox example.wav -b 8 -c 1 -r 8000 example.au

This example command takes an input file called example.wav and converts it to 8 bits per sample, mono (or 1 channel), with a sample rate of 8000 Hz and writes it out to a file with an AU format. The sox package also contains two other utilities, play and rec. With these, you have another way of playing audio files and recording audio to a file. You also have the full spectrum of processing and filters available from sox.

You may ask why I picked this particular example? This is so that I can show you one last interesting trick. On Linux systems, you can simply cat this output file (with this specific file format) directly to the device file /dev/audio. This dumps the output directly to the sound card. So, if you want to be sneaky, you can convert some files to the AU file format with the sox command above, copy them over to your target machine, and simply cat them to /dev/audio when you want to make a nuisance of yourself. Hopefully you now have some ideas on how to enjoy your music, and how to play with audio files, without the overhead of the GUI applications available.