• The IF statement:
    • The IF command is used to compare results.
    • There are three forms of the IF command:
      Block
      This is the traditional multi-line IF seen in many programming languages.
      This can be combined with ELSEIF and ELSE clauses.
      One-Line
      This is an IF statement with a single action that, as the name implies, is all on a single line.
      Quick Check
      This is a special form of the IF statement that can only be used in the shell.
      This form evaluates the expression and prints the value to the terminal.