Indentation is whitespace at the beginning of each line, and may be used to more clearly denote the hierarchical structure of your code, thus making it more readable. Each of these commands change the way that the current line is indented, either by altering the indentation manually or by automatically applying language-specific heuristics to determine how the line should be indented. If a number of lines are selected, these commands will operate on each line in the selection instead.