Additive color mixing begins with black and ends with white; as more color is added, the result is lighter and tends to white. The RGB colors are light primaries and colors are created with light. Percentages of red, green, & blue light are used to generate color on a computer screen.
In shell scripting we often need to check if file or directory exists and take appropriate action. This post show you how to check it and how this check use in your script. For checking we will use file test operators -f for file and -d for directory, which return TRUE if file or directory exists. And here is output of the script.
A shell script is a computer program designed to be run by the Unix shell, a command-line interpreter. The various dialects of shell scripts are considered to be scripting languages. Typical operations performed by shell scripts include file manipulation, program execution, and printing text. A script which sets up the environment, runs the program, and does any necessary cleanup, logging, &c is called a wrapper.