Embedded Guru

Terminals can display texts in color as well as allow formatting with the help of escape sequences. Escape Sequence = Escape Character + FormatCode+'m' = "<esc>[FormatCodem" Escape character can be '\e', \033, \x1B The format code for Red is 31, so to print the Text in Red. echo -e '\033[31mHello World' The -e option of the echo command enable the parsing of the escape sequences. If you want the background to be Red the format code is 41. echo -e '\033[41mHello World' We can add multiple format codes with a ; as delimeter  echo -e '\033[42;31mHello World' To remove all formatting, the format code is 0. echo -e '\033[31mHello \033[0mWorld' It is better to add \033[0m at the end of each colored text. To Bold the text, the format code is 1. echo -e '\033[1mHello World' You can find more format codes in the below link: https://misc.flogisoft.com/...

When you run ./myscript.sh, a new child process of shell is created and script is run there. So, if you export any variables in the script, after the script completes execution, they don't exist. Whereas when you run source myscript.sh or '. myscript.sh', it won't create a child process, instead it will run in the same environment, hence values of environmental variables persist. The below is the screenshot of a simple script which exported a variable and the result is different when you run ./myscript.sh or source myscript.sh Modified the script to print the PID and PPID of the script, with 'source myscript.sh', the PID of the shell script is the PID of the shell, whereas in './myscript.sh' it is different.