Settings for indentation
The shiftwidth setting controls how large an indentation is in terms of spaces. This is different from the tabstop setting that specifies how large an actual tab character is.
If shiftwidth is set to 4 and tabstop is left at the default 8, one indentation will use 4 spaces, but two indentations will use one tab.
Use the expandtab setting to always use spaces when indenting.
When the autoindent setting is enabled, a new line will use the same amount of indentation as the previous line. The smartindent setting adds syntax-aware rules for increasing and decreasing the automatic indentation.