hello-world.bf

# Source: https:##en.wikipedia.org#wiki#Brainfuck#Hello_World! 

[ # This program prints "Hello World!" and a newline to the screen, its 
  # length is 106 active command characters. [It is not the shortest.] 

  # This loop is an "initial comment loop", a simple way of adding a comment 
  # to a BF program such that you don't have to worry about any command 
  # characters. Any ".", ",", "+", "-", "<" and ">" characters are simply 
  # ignored, the "[" and "]" characters just have to be balanced. This 
  # loop and the commands it contains are ignored because the current cell 
  # defaults to a value of 0; the 0 value causes this loop to be skipped. 
]
8+               # Set Cell #0 to 8 
[
    >++++               # Add 4 to Cell #1; this will always set Cell #1 to 4 
    [                   # as the cell will be cleared by the loop 
        >++             # Add 2 to Cell #2 
        >+++            # Add 3 to Cell #3 
        >+++            # Add 3 to Cell #4 
        >+              # Add 1 to Cell #5 
        <<<<-           # Decrement the loop counter in Cell #1 
    ]                   # Loop till Cell #1 is zero; number of iterations is 4 
    >+                  # Add 1 to Cell #2 
    >+                  # Add 1 to Cell #3 
    >-                  # Subtract 1 from Cell #4 
    >>+                 # Add 1 to Cell #6 
    [<]                 # Move back to the first zero cell you find; this will 
                        # be Cell #1 which was cleared by the previous loop 
    <-                  # Decrement the loop Counter in Cell #0 
]                       # Loop till Cell #0 is zero; number of iterations is 8 

# The result of this is: 
# Cell No :   0   1   2   3   4   5   6 
# Contents:   0   0  72 104  88  32   8 
# Pointer :   ^ 

>>.                     # Cell #2 has value 72 which is 'H' 
>---.                   # Subtract 3 from Cell #3 to get 101 which is 'e' 
+++++++..+++.           # Likewise for 'llo' from Cell #3 
>>.                     # Cell #5 is 32 for the space 
<-.                     # Subtract 1 from Cell #4 for 87 to give a 'W' 
<.                      # Cell #3 was set to 'o' from the end of 'Hello' 
+++.------.--------.    # Cell #3 for 'rl' and 'd' 
>>+.                    # Add 1 to Cell #5 gives us an exclamation point 
>++.                    # And finally a newline from Cell #6