Explanation: When we have to execute a series of commands altogether, we store them in a file which is itself executed as a shell script. A shell script is basically a computer program designed to be run by the UNIX shell.

Explanation: It’s not mandatory to save script files with .sh extension but we do so for our own convention as it makes it easy to match them with wildcards.

Explanation: Shell scripts are executed in a separate child process, and this sub-shell need not be of the same type as our login shell. In other words, even if our login shell is bourne, we can use a Korn sub-shell to run our script.

Explanation: Before we run the script, it is essential to make the script executable first. After that invoke the script name to run the script. For making the script executable, we have to use chmod +x script_name.

Explanation: We know that shell scripts are executed by a child shell. But we can also explicitly spawn a child of our own choice by using the sh command along with script name as an argument. When used in this way, the interpreter line is ignored by the shell.

Explanation: read command is the shell’s internal tool for taking input from the user i.e. it makes the scripts interactive.

read FirstName LastName

Explanation: Shell scripts can also take input from command line. When arguments are specified with a shell script, they are assigned to certain special variables called positional parameters.

Explanation: Command line arguments are stored into positional parameters. The first argument is read by the shell into the parameter $1, second argument in $2 and so on.

Explanation: There are some special parameters used by the shell. One of which is $*, which stores the complete set of positional parameters as a single string.