Arch 2010.05 Setup - part 2

Now that we've secured access to our Arch 2010.05 slice we can update it and get it ready for the rest of the server install.


Moving on

In part 1 of the Arch 2010.05 setup we completed the ssh configuration along with a basic iptables setup.

Now let's run some checks and install some personal configuration files to make life easier. Once done, we can update the install and create a solid base for the 'meat' of the server.

OS check

First thing is to confirm what OS we're using. We know we should be using Arch, so to make sure let's see if there's an "arch-release" file:

ls /etc/arch-release

Recent versions of Arch don't put anything in that file, they just create it empty. So that's about the best way to check. So long as the output of the "ls" looks like...

/etc/arch-release

...you're running Arch.

You can also look inside /etc/issue:

$ cat /etc/issue

Arch Linux \r  (\n) (\l)

Good enough.

Using free

Memory usage should be very low at this point but let's check using 'free -m' (the -m suffix displays the result in MB's which I find easier to read):

free -m

It's nice to know what is going on so let's look at that output:

.                  total       used       free     shared    buffers     cached
Mem:           254        55          199          0           2               21
-/+ buffers/cache:      30          223
Swap:            511        0           511

The line to take notice of is the second one as the first line includes cached memory - in this demo slice I have 254MB memory in total with 30MB actually used, 223MB free and no swap used. Nice.

.bashrc

Normally the "ls" command doesn't list files that start with a period. Those are usually configuration files or directories, and ls hides them so they don't clutter up your directory view. To see all of what's there, run:

ls -a ~

The "-a" option is what tells ls to list all files, not just the non-configuration files.

You'll see several files, but let's focus on ".bashrc" right now. This is ultimately where your user environment (the "shell") will look for its settings. Go ahead and open it for editing:

nano ~/.bashrc

Inside you'll see some shell script commands — don't worry if you don't understand it all. Anything we add at the end of the file will override what came before. If you want to, say, change your prompt, you don't necessarily need to figure out what all the "if" statements in there by default are for, and which line you need to edit. You can just add your own setting at the end.

Custom prompt

With that in mind, let's look at how to change your prompt. At its simplest, the prompt's format is set with the "PS1" environment variable. It consists of some numbers that determine color and some codes that act as stand-ins for variables like the current working directory and your hostname. To set your prompt to just your hostname and working directory, both in different colors, you could add this line to the end of the .bashrc file:

PS1='\[\033[0;35m\]\h\[\033[0;33m\] \w\[\033[00m\]: '

The chunks like "0;35m" and "0;33m" are what control the colors - those are pink and brown, for example. Other colors you can substitute include "0;32m" for green and "0;36m" for blue — it's just a matter of changing those numbers.

Other important parts of that jumbled collection of characters are "\h" and "\w", which represent the hostname and working directory, respectively. If you wanted to include your username in the prompt you could add the "\u" code along with an "@" symbol, and it would look like this:

PS1='\[\033[0;35m\]\u@\h\[\033[0;33m\] \w\[\033[00m\]: '

Before we see what that will look like, however, let's also look at another useful feature of your shell, aliases.

Alias

The "alias" keyword lets you set a shortcut for another command. Some examples to get you started, which can be added to the end of your .bashrc file:

alias free="free -m"
alias update="sudo pacman -Sy"
alias install="sudo pacman -S"
alias upgrade="sudo pacman -Syu"
alias remove="sudo pacman -R"
alias search="pacman -Ss"

They're pretty simple examples, and are just meant to save you a little typing. Notice that you can essentially replace a command with an alias, like we did by setting the alias "free" to be a shortcut for "free -m". With that alias set, when you type "free" on the command line, behind the scenes the shell actually runs "free -m", so you don't have to type the extra characters to get the memory usage numbers in megabytes.

Similarly, those other aliases are shorthand for some aptitude commands to update or install packages. Since "sudo" is run behind the scenes you'll still have to type your password, but at least before that you won't have to type as much to run an update or install a package.

To activate the changes you've made to the .bashrc file, either log out and log back in or enter this command:

source ~/.bashrc

If you set a value for "PS1" above, you'll see your prompt change. Feel free to go back and change the colors or format of the prompt, or add your own aliases.

Set locale

You can check the current locale setting for your slice by running:

/usr/bin/locale

If the code doesn't match what it should be for the localization you would like to use for your slice (or if it uses a generic locale like 'POSIX'), you'll need to make a couple changes.

First, open the "/etc/locale.gen" file for editing:

sudo nano /etc/locale.gen

Inside you'll see a list of possible locales. The lines with "#" in front of them are commented out, which means they are not actively supported right now. The lines without the "#" are active.

A typical entry in this file looks something like:

en_US.UTF-8 UTF-8

The first part, "en", represents the language used. The second part, "US", is the country of the locale. The ".UTF-8" in the example indicates the Unicode version of the locale (recommended), and the last "UTF-8" also tells the system to use Unicode.

A complete list of language and region codes can be found here. You can search the file in nano with "control-W". That makes it easier to jump to a locale once you know the language and country code combination you want. If the combination isn't already in the file, you can add a line for it yourself.

For example, if you wanted to enable the Welsh language (cy) for the Great Britain region (GB), you would add or uncomment a line that contains:

cy_GB.UTF-8 UTF-8

To disable an enabled locale just insert a "#" in front of that line to comment it out.

Once the locale.gen file is the way you want it run the command:

sudo /usr/sbin/locale-gen

With the locales generated you can set the default locale by editing the rc.conf file:

sudo nano /etc/rc.conf

Toward the beginning of the file will be the LOCALE entry:

LOCALE="en_US.UTF-8"

Change the locale listed to the one you want to use as the default.

To change the locale without logging out you can pass the locale name to an environment variable:

export LANG=en_US.UTF-8

You can also add that line to the .bashrc file to change the locale for a particular user when they log in (if they want to use something other than the system default).

In any event, you can run "locale" again at any time to check your current locale. To test the change to the system default locale you'll need to log out then log back in.

Package repositories

An Arch server comes with a basic set of repositories.

Have a look at the enabled repositories by running:

cat /etc/pacman.conf

You should see some options at the top and a list of repositories at the bottom, with a good amount of commented instructions scattered throughout. The actual repositories are lines that look like:

[core]
# Add your preferred servers here, they will be used first
Include = /etc/pacman.d/mirrorlist

[extra]
# Add your preferred servers here, they will be used first
Include = /etc/pacman.d/mirrorlist

The "Include = /etc/pacman.d/mirrorlist" lines tells the package manager (pacman) to use the official list of mirrors. You can edit the /etc/pacman.d/mirrorlist file if you want to change the official mirrors that your system will use (by commenting and uncommenting lines).

If you want to add unofficial repositories or mirrors (like the test repository), do so in the /etc/pacman.conf file.

A word of caution on unofficial and testing repositories: Unsupported repositories may not receive any security updates should a flaw be discovered.

Keep in mind it is a server we are building and security and stability are paramount.

Update

Now we can update the package list that pacman uses.

sudo pacman -Sy

NOTE: If you have used the .bashrc aliases shown above you just need to enter 'update' as the alias will use the entire command. I've put the whole thing here so you know what is happening.

Now we have set the locale and updated the repositories, let's see if there are any upgraded packages available:

sudo pacman -Su

You may be asked to upgrade the pacman utility first. Do so, then run the upgrade command again.

You may be asked about replacing some packages with other packages. This usually means that a package has been deprecated and replaced with a newer one, so it's generally safe to say yes to those queries.

As with all installs have a careful look at the list of updated packages and, once happy, press 'y' to continue.

That's really the basics done for the Slice.

Once any updates have been installed, we can move on to installing some essential packages.

Development Tools

Arch has some handy meta-packages that include sets of pre-defined programs required for a single purpose.

So instead of installing a dozen different package names, you can install just one meta-package. One such package is called 'base-devel', a collection of development tools. Issue the command:

sudo pacman -S base-devel

Notice the programs that are to be installed include gcc, make, patch and so on. All these are needed for many other programs to install properly. A neat system indeed.

Enter 'y' and install them.

Now we have the necessary packages should we want to build an application from source.

Done

The console is now informative and less drab, locales have been configured and basic compile tools have been installed. Quite a lot happening here but now we have a more secured Slice with updated packages ready for the meat of the server to be put in place.

  • -- Jered
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