2007-05-16
SHPEGS - Solar Heat Pump Electrical Generation System
I have discovered an interesting Open Source project related to energy: SHPEGS. From the site's front page: "This is a project to design and build a system that uses a combination of direct and indirect solar collection to generate electricity and store thermal energy in an economical, environmentally friendly, scalable, reliable, efficient and location independent manner using common construction materials."
This is in line with my previous post about alternative energy sources.
This is in line with my previous post about alternative energy sources.
2007-05-11
Encryption One Liner
We had an interesting mail this morning on the GLUG that demonstrated a one liner for encrypting and decrypting text using OpenSSL.
Here is the demo:
Here is the demo:
$ echo foo | /usr/bin/openssl enc -e -md md5 -aes-128-cbc -a -k "bar"
U2FsdGVkX18iDqnxzgjr3gk39hShVjLgiBQZ2mFKQOk=
$ echo "U2FsdGVkX18iDqnxzgjr3gk39hShVjLgiBQZ2mFKQOk=" | /usr/bin/openssl enc -d -md md5 -aes-128-cbc -a -k "bar"
foo
Calculating date and time from Unix time in Excel
A while back I had a problem where I needed to convert Unix timestamps in MS Excel to proper date and time fields. Well, I experimented and came up with a simple solution:
here is what I discovered:
* Excel stores the date as an integer number with a starting point of 1900-01-01
* Unix time start on 1970-01-01
So I calculated the difference between the two, and came up with 25569.
Time is calculated as a fraction from date. Since I live in South Africa (GMT+2), I need to also add two hours, or 0.08333
Assuming the Unix time stamp is in column A (A1, A2 etc), my formula now looks like this:
here is what I discovered:
* Excel stores the date as an integer number with a starting point of 1900-01-01
* Unix time start on 1970-01-01
So I calculated the difference between the two, and came up with 25569.
Time is calculated as a fraction from date. Since I live in South Africa (GMT+2), I need to also add two hours, or 0.08333
Assuming the Unix time stamp is in column A (A1, A2 etc), my formula now looks like this:
Code:
=(A1/86400)+25569.08333
2007-05-09
Dynamic Perl source code highlighting on web pages
Yes, the title is a mouth full :)
I have discovered a handy AJAX implementation to highlight tagged areas of Perl source code on a web page. I think it could be very handy.
I wish I had some more time to play with all these new web technologies, as I think it is now possible to have syntax highlighting as you type in an edit box. Granted that an AJAX implementation will consume some bandwidth - but is that still an issue?
Maybe one of these fine days I can sit down and figure it out.
I have discovered a handy AJAX implementation to highlight tagged areas of Perl source code on a web page. I think it could be very handy.
I wish I had some more time to play with all these new web technologies, as I think it is now possible to have syntax highlighting as you type in an edit box. Granted that an AJAX implementation will consume some bandwidth - but is that still an issue?
Maybe one of these fine days I can sit down and figure it out.
2007-05-08
Optimize Perl
IBM has a rather good (and short) article about optimizing Perl. The subject is also well covered when you search Google for "perl optimization".
Well, happy coding/optimizing :)
Well, happy coding/optimizing :)
