For parameters that are treated as numbers, use decimal (the number) or hexadecimal (with 0x prepended to it, i.e. 0x12345AB), or octal (numbers beginning with a 0 and no x).
Colors should be set in hexadecimal RGB format, like HTML but without the #.
\c IntCmp 1 0x1 lbl_equal
\c
\c SetCtlColors $HWND CCCCCC
\\<b\\>Strings\\</b\\>
To represent strings that have spaces, use quotes:
\c MessageBox MB_OK "Hi there!"
Quotes only have the property of containing a parameter if they begin the parameter. They can be either single quotes, double quotes, or the backward single quote.
To extend a command over multiple lines, use a backslash (\\) at the end of the line. The next line will effectively be concatenated to the end of it. For example:
If a file named "nsisconf.nsh" in the config directory exists, it will be included by default before any scripts (unless the /NOCONFIG command line parameter is used). The config directory on Windows is the same directory as makensis.exe is in. On other platforms this is set at install time and defaults to $PREFIX/etc/. You can alter this at runtime, see \k{usageenvironment} for more information.