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.
To verify your file was created, type the following command at the prompt and press Enter. NOTE: The command starts with a lowercase âLâ and the option (-l) is also a lowercase âLâ. ls-l sample.txt. You should see directory listing of your file, as shown below.The âcatâ command can also be used to view the contents of your file. To do this, type the following command at the prompt and press Enter.cat sample.txt. The contents of the file is printed to the screen and you are returned to the prompt.ou should see directory listing of your file, as shown below. The âcatâ command can also be used to view the contents of your file. To do this, type the following command at the prompt and press Enter. cat sample.txt. The contents of the file is printed to the screen and you are returned to the prompt.