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.
2.1.1. A shell script is a sequence of commands for which you have a repeated use. This sequence is typically executed by entering the name of the script on the command line. Alternatively, you can use scripts to automate tasks using the cron facility.Another use for scripts is in the UNIX boot and shutdown procedure, where operation of daemons and services are defined in init scripts. To create a shell script, open a new empty file in your editor.his sequence is typically executed by entering the name of the script on the command line. Alternatively, you can use scripts to automate tasks using the cron facility. Another use for scripts is in the UNIX boot and shutdown procedure, where operation of daemons and services are defined in init scripts.