Perl Variable Aliases

When a variable is passed by value, Perl does not create a copy of the contents to build @_ but, rather, creates an alias to the contents of the original variable. Therefore, a memory blow-up is caused by reading from @_.

Cross Compiling Hint for Linux From Scratch has a new Maintainer

The crosscompiling hint is now maintained by Ted Bullock.


For a series of measurements $x_i = x_1, \dots, x_n$, it is useful to examine the magnitude of a certain fraction of the number of values.

Agent Forwarding

When logging into different hosts and over several hops generating key pairs and distributing public keys becomes a hassle with each additional host. At the same time security (i.e. key integrity and authentication) becomes a problem because breaking into one of your hosts might possibly compromise your private key and allow the attacker to login to one or more of the hosts you’re using.


keychain is a manager for the SSH agent. It ensures that there is a single running SSH agent which can be used from several shells at the same time.

Session Multiplexing

Although the OpenSSH client supports session multiplexing as of version 3.9, I understand that the server offers the support for some time. It allows several logins to share the same session and therefore the same login credentials. You will not have to authenticate everytime you open a session.

XML Validator

This is a validator for XML documents with the foillowing features:

Subversion Tunnels

Subversion supports sending its communication via custom tunnels in addition to the predefined SSH tunnel. New tunnels are defined in the [tunnels] section of your global configuration in /etc/subversion/config or your private configuration in ~/.subversion/config


The OpenSSL library provides access to SSL encrypted tunnels. Most of its functionality is accessible via the openssl command which is shipped with the OpenSSL package.

Null Entity Resolver

Instead of permitting the XML parser to download document type definitions, this entity resolver returns an empty string for all entities.