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### 4.1 Options

Many string or integer options are easy to modify using `M-x customize-option`. For example, to modify the option that controls printing, you would run `M-x customize-option <RET> mh-lpr-command-format <RET>`. In the buffer that appears, modify the string to the right of the variable. For example, you may change the `lpr` command with ‘`nenscript -G -r -2 -i'%s'`’. Then use the ‘`State`’ combo box and select ‘`Save for Future Sessions`’. To read more about `mh-lpr-command-format`, see Printing.

Options can also hold boolean values. In Emacs Lisp, the boolean values are `nil`, which means false, and `t`, which means true. The `customize-option` function makes it easy to change boolean values; simply click on the toggle button in the customize buffer to switch between ‘`on`’ (`t`) and ‘`off`’ (`nil`). For example, try setting `mh-bury-show-buffer-flag` to ‘`off`’ to keep the MH-Show buffer at the top of the buffer stack. Use the ‘`State`’ combo box and choose ‘`Set for Current Session`’ to see how the option affects the show buffer. Then choose the ‘`Erase Customization`’ menu item to reset the option to the default, which places the MH-Show buffer at the bottom of the buffer stack.

The text usually says to turn on an option by setting it to a non-`nil` value, because sometimes values other than ‘`on`’ are meaningful. An example of this is the variable `mh-mhl-format-file` (see Viewing). Other options, such as hooks, involve a little more Emacs Lisp programming expertise.

You can browse all of the MH-E options with the `customize-group` function. Try entering `M-x customize-group <RET> mh <RET>` to view the top-level options as well as buttons for all of the MH-E customization groups. Another way to view the MH-E customization group is to use `M-x mh-customize <RET>`.