Bash Script

1. Calculating

The Double Parentheses Construct

Similar to the let command, the ((...)) construct permits arithmetic expansion and evaluation.

In its simplest form, a=$(( 5 + 3 )) would set "a" to "5 + 3", or 8.

However, this double parentheses construct is also a mechanism for allowing C-type manipulation of variables in Bash.

Reference: http://www.linuxtopia.org/online_books/advanced_bash_scripting_guide/dblparens.html

2. Array

bash下array的幾種使用方法

Reference: http://go-linux.blogspot.com/2007/03/basharray.html