How are variables accessed (e.g., printed) in a shell script?

In a shell script, variables are accessed (or printed) by prefixing the variable name with a dollar sign ($). Here are some examples of how to access and print variables:

1. Basic Variable Access: To print the value of a variable, you can use the echo command:

   my_variable="Hello, World!"
   echo $my_variable  # Output: Hello, World!
   

2. Using Variables in Strings: You can include variables within strings:

   name="Alice"
   greeting="Hello, $name!"
   echo $greeting  # Output: Hello, Alice!
   

3. Accessing Variables in Commands: Variables can be used as arguments in commands:

   file_name="example.txt"
   touch $file_name  # Creates a file named example.txt
   

4. Using Curly Braces: For clarity, especially when concatenating variables with strings, you can use curly braces:

   name="Bob"
   echo "Welcome, ${name}!"  # Output: Welcome, Bob!
   

5. Accessing Environment Variables: You can also access environment variables in the same way:

   echo $HOME  # Prints the home directory of the current user
   

These methods allow you to effectively access and print the values of variables in shell scripts.