#+TITLE: User-defined variables in wiki.conf 
#+SHORT-TITLE: wiki.conf
#+KEYWORDS: website builder, configuration, variables
#+TOC-KEYWORDS: manuals
#+DESCRIPTION: variables are useful to keep your web pages updated

* Related articles
[[variables][predefined variables in wiki.conf]]

* Integer variables allow arithmetic
There are two kinds of variables in *wiki.conf*: integer and string ones.

Suppose a small business owner runs a business website and updates the prices once in a while. If some service is mentioned on several pages, it might be hard to synchronize its price across all pages.

Updates like that become easier using variables in *wiki.conf*, for example:\\
*laborRate=33*

** Example
Using this variable, on one web page we may write\\
"you can hire me at $\<\<laborRate\>\>\/hour",\\
and somewhere else\\
"I will serve you for $\<\<8*\<\<laborRate\>\>\>\>\/day"\\

During the compilation of the text source to HTML, \<\<laborRate\>\> will be replaced with its value 33, and \<\<8*\<\<laborRate\>\>\>\> will be replaced by 264. (Numerical variables support arithmetic and parenthesis).

* Updating a variable updates all web pages
Suppose that next year US dollar looses another 7% of its value and we decide to adjust the pay rate.
All we have to do then is to change the value in *wiki.conf*:\\
*laborRate=36*

After that,
all web pages referring to *laborRate* variable will be properly updated. 

* String variables
Variables are handy not only for business websites.

For example, a playboy (or a playgirl) who is changing friends often, can define a variable\\
*friendsLinkedin=jamesBond*

Using this variable, they can [[http://howto.leanws.com/links][insert a link]] to friend's linkedin account as follows:\\
"Please visit\\
\[\[https:\/\/www.linkedin.com\/in\/\<\<friendslinkedin\>\>\]\[my friend's linkedin\]\]\\
and hire them ASAP or I will change him to\\
*friendsLinkedin=IndianaJones*\\
in my *wiki.conf* file."