Shell Programming
Loops
A loop is a block of code that iterates a list of commands as long as the loop control condition is true.
Dialog Utility
A Dialog Box is a temporary window an application runs to convey important information to the users. These dialog boxes can be used to display warnings, errors, and also any additional inputs needed by the system from End Users.
Functions
Like real programming languages, shell has functions, though in a somewhat limited implementation. A function is a subroutine, a code block that implements a set of operations, a black box that performs a specified task.
Here Documents
A here document is a special-purpose code block. It uses a form of I/O redirection to feed a command list to an interactive program or a command, such as ftp, cat, or the ex text editor.
Arrays
Arrays are a collection of contiguous elements that can be accessed by a subscript.