When installing a new plugin, or upgrading an existing theme, plugin, or WordPress itself, you may be asked for FTP details. But, you say, I thought I had this configured to update directly. Here's how to force WordPress to upgrade without FTP.

In your wp-config.php file, add a line near the top:

define('FS_METHOD', 'direct');

This forces WordPress to write to files directly. Once this is done, you will get error messages that better explain what isn't working.

For example, you may need group write privileges on the wp-content/upgrade directory:

chmod g+w wp-content/upgrade

If you get this error:

Could not remove the old plugin.

you will also need to ensure there is group write on all the plugins themselves:

chmod -R g+w wp-content/plugins

Update July 2012: A more robust solution, from within the cpan program, is: install Bundle::CPAN

A common Perl module, ReadLine is especially handy when running the cpan program to install other modules, as it lets you up-arrow through previous commands, edit your command with the arrows and so on.

At least on Ubuntu 10.10 ... CPAN will not install it. You get this error:

cpan> <span style="text-decoration: underline;">install Term::ReadLine</span>
Running install for module 'Term::ReadLine'
CPAN: Data::Dumper loaded ok (v2.124)
'YAML' not installed, falling back to Data::Dumper and Storable to read prefs '/home/luser/.cpan/prefs'
The most recent version "1.05" of the module "Term::ReadLine"
is part of the perl-5.12.2 distribution. To install that, you need to run
 force install Term::ReadLine   --or--
 install J/JE/JESSE/perl-5.12.2.tar.gz
Running make test
 Can't test without successful make
Running make install
 Make had returned bad status, install seems impossible
Failed during this command:
 JESSE/perl-5.12.2.tar.gz                     : make NO isa perl

(typed text is underlined.)

The proper Ubuntu way to get ReadLine installed is to:

$ <span style="text-decoration: underline;">sudo apt-get install libterm-readline-gnu-perl </span>

You probably also want to install Term::ReadLine::Perl (and) Term::ReadKey

Alternately, use the single-command-line cpanm to install one or more Perl modules and all dependencies, like this:

$ <u>cpanm Term::ReadLine Term::ReadLine::Perl Term::ReadKey</u>

You might also check Racker Hacker's article on auotmatically installing CPAN dependencies without requiring confirmation. Note, this will not prevent modules like those in the Test suite from asking:

<em>{this module} </em>is just needed temporarily during building or testing.
Do you want to install it permanently? [yes]

The 'cpan' command won't "install GD" as it complains that the GD library is not found. Although GD is installed in Ubuntu by default, you need the developer library. What you want instead is:

$ sudo apt-get install libgd-gd2-perl
$ perl
use GD;

(works!)

I'm moving my internal server to new hardware and wanting to load CentOS 5.2 ... without downloading a half dozen CDs or a 4+GB DVD image... half of which I probably won't need, or which will be replaced by updates anyway.

Fortunately, the latest releases have a Net install image, which is only about 8MB. Look for this file on the mirrors:

CentOS-5.2-x86_64-netinstall.iso

for the 64-bit version, or as appropriate for your architecture.

Booting that CD asks about your keyboard and such, and then asks for an Installation Method. Pick HTTP, and you'll be asked for the website and directory. Strangely, there's no automatic list of mirrors, so you have to do some scouting. I suggest using the mirror from singlehop -- enter this:

Web site name: yum.singlehop.com
CentOS directory: CentOS/5.2/os/x86_64

The first file downloaded is images/stage2.img which is about 90MB, and then off you go.

If you're setting up a large number of servers, you probably want to either download the ISOs or install a local mirror.