Category: Programming

A big part of my work has to do with code. I’ve worked as system administrator – installing, patching, and configuring someone else’s code. I’ve worked as independent programmer, writing code on my own. I also programmed as part of the team. And on top of that, I worked as Team Leader and Project Manager, where I had to interact a lot with programmers. Programming world on its own is as huge as the universe. There is always something to learn. When I find something worthy or something that I understand enough to write about, I share it in this category.

Working with hashes in Perl

There are several very useful modules at CPAN to work with Perl hashes. Here is a short list to get you started.

Tie::Hash::Approx – use key approximation to find values.
Tie::AliasHash – use multiple keys for a single value.
Tie::Hash::Expire – expire keys in hash after a predefined period of time.
Bloom::Filter, Bloom16, Text::Bloom – implementation of Bloom’s filter algorithm.
Tie::Hash::Regex, Tie::RegexpHash – use regular expressions to match hash keys.
Tie::SortHash, Tie::Hash::Rank, Tie::InsertOrderHash, Tie::Hash::Indexed, Tie::IxHash – sorting hashes by key, by value; keeping hashes sorted, keeping elements in the same order they were inserted, etc.
Tie::RangeHash – associating values with a range of keys (e.g.: from 1 to 6 is “a”, from 7 to 10 is “b”, etc)

I’ve used this article (in Russian) as a base for this post.

Epigrams on Programming

Alan J. Perlis of Yale University has combined a nice collection of Epigrams on Programming. These are both funny and useful at the same time one-lines that help staying in the right direction when designing and implementing computer programs.

Building a Vector Space Search Engine in Perl

There is a very interesting article at Perl.com. It is about building a search engine using perl language. The interesting part is that the article is not about the usual reverse index type search engines. It takes a different approach – vector space searching.

Reading the article reminded me of the few things:

The subject of searching is interesting to me.
Perl is great!
Linear algebra is actually useful and I should take it again (and pass it this time).

Bash prompts

Maintainer of the Bash Prompt HOWTO, it turns out, also keeps a small website with examlpes of different bash prompts. It provides screenshots together with code for some really wicked prompts. If you are into that kind of things, but all of ideas, than check the site out. Maybe you’ll find something for yourself. :)

Port forwarding with Putty

Putty, it seems, is the most popular Telnet/SSH client for MS Windows (although it does run UNIX too). It is small, free, stable, and flexible. It has all the functionality one will ever need (with a few exceptions, of course).

Secure Shell (SSH) provides for a number of interesting uses. One of them is port forwarding, also known as tunneling. It is used when there is a need to pass encrypted information between two hosts while the original protocol for information does not support encryption, or another encryption level is required for some reason.

Apparently, Putty can help poor Windows souls with port forwarding too. This step-by-step tutorial with a lot of pictures shows exactly how to do it. The example used is encrypted email traffic.