3-1 if condition to determine the installation of Apache 1

Conditional tests can be returned if they are true or false.
Use double quotation marks when comparing strings, and if the variables are not there may be an error.

Permissions, who execute on who has permission
A script is a stack of commands that you normally use, from top to bottom execution
Create a script that features Apache software Installation

Write scripts with notes for easy reading.
Start a virtual machine first:

#rpm –qa httpd//to determine if Apache has been installed
In the script cannot complete, can find a terminal in advance to knock over the command
Permanently close SELinux

Temporarily close SELinux

Temporarily delete a gateway

form the habit of writing a frame first

Note: Some commands do not return TRUE or false

3-1 if condition to determine the installation of Apache 1