Table of Contents

Syslinux

There are two menu systems included with SYSLINUX, the advanced menu system, and the simple menu system.

The advanced menu system

The advanced menu system, written by Murali Krishnan Ganapathy, is located in the menu/ subdirectly. It allows the user to create hierarchial submenus, dynamic options, checkboxes, and just about anything you want. It requires that the menu is compiled from a simple C file, see menu/simple.c and menu/complex.c for examples.

The advanced menu system doesn't support serial console at this time.

See menu/README for more information.

The simple menu system

The simple menu system is a single module located at com32/modules/vesamenu.c32 (graphical) or com32/modules/menu.c32 (text mode only). It uses the same configuration file as the regular SYSLINUX command line, and displays all the LABEL statements.

To use the menu system, simply make sure [vesa]menu.c32 is in the appropriate location for your boot medium (the same directory as the configuration file for SYSLINUX, EXTLINUX and ISOLINUX, and the same directory as pxelinux.0 for PXELINUX), and put the following options in your configuration file:

DEFAULT menu.c32
PROMPT 0

There are a few menu additions to the command line, all starting with the keywords MENU or TEXT; like the rest of the SYSLINUX config file language, it is case insensitive:

MENU TITLE title

Give the menu a title. The title is presented at the top of the menu.

MENU HIDDEN

Do not display the actual menu unless the user presses a key. All that is displayed is a timeout message.

MENU SEPARATOR

Insert an empty line in the menu.

MENU LABEL label

(Only valid after a LABEL statement.) Changes the label displayed for a specific entry. This allows you to have a label that isn't suitable for the command line, for example:

# Soft Cap Linux
LABEL softcap
	MENU LABEL Soft Cap ^Linux 9.6.36
	KERNEL softcap-9.6.36.bzi
	APPEND whatever
# A very dense operating system
LABEL brick
	MENU LABEL ^Windows CE/ME/NT
	KERNEL chain.c32
	APPEND hd0 2

The ^ symbol in a MENU LABEL statement defines a hotkey. The hotkey will be highlighted in the menu and will move the menu cursor immediately to that entry.

Reusing hotkeys is disallowed, subsequent entries will not be highlighted, and will not work.

Keep in mind that the LABELs, not MENU LABELs, must be unique, or odd things will happen to the command-line.

MENU INDENT count

(Only valid after a LABEL statement.) Will add “count” spaces in front of the displayed menu entry.

MENU DISABLE

(Only valid after a LABEL statement.) Makes the entry unselectable. This allows you to make a section in your menu with different options below it. for example:

# Entries for network boots
LABEL -
	MENU LABEL Network:
	MENU DISABLE

# Soft Cap Linux
LABEL softcap
	MENU LABEL Soft Cap ^Linux 9.6.36
	MENU INDENT 1
	KERNEL softcap-9.6.36.bzi
	APPEND whatever

# Dos 6.22
LABEL dos
	MENU LABEL ^Dos 6.22
	MENU INDENT 1
	KERNEL memdisk
	APPEND initrd=dos622.imz

# Separator
MENU SEPARATOR

# Entries for local boots
LABEL -
	MENU LABEL Local:
	MENU DISABLE

# Windows 2000
LABEL w2k
	MENU LABEL ^Windows 2000
	MENU INDENT 1
	KERNEL chain.c32
	APPEND hd0 1

# Windows XP
LABEL xp
	MENU LABEL Windows ^XP
	MENU INDENT 1
	KERNEL chain.c32
	APPEND hd0 2
MENU HIDE

(Only valid after a LABEL statement.) Suppresses a particular LABEL entry from the menu.

MENU DEFAULT

(Only valid after a LABEL statement.) Indicates that this entry should be the default. If no default is specified, use the first one.

TEXT HELP
Help text ...
... which can span multiple lines
ENDTEXT

(Only valid after a LABEL statement.)

Specifies a help text that should be displayed when a particular selection is highlighted.

MENU PASSWD passwd

(Only valid after a LABEL statement.)

Sets a password on this menu entry. “passwd” can be either a cleartext password, a SHA-1 encrypted password (starting with $4$), or and MD5 encrypted password (starting with $1$).

Use the included Perl scripts “sha1pass” or “md5pass” to encrypt passwords. MD5 passwords are compatible with most Unix password file utilities; SHA-1 passwords are probably unique to SYSLINUX. Obviously, if you don't encrypt your passwords they will not be very secure at all.

If you are using passwords, you want to make sure you also use the settings “NOESCAPE 1”, “PROMPT 0”, and either set “ALLOWOPTIONS 0” or use a master password (see below.)

If passwd is an empty string, this menu entry can only be unlocked with the master password.

MENU MASTER PASSWD passwd

Sets a master password. This password can be used to boot any menu entry, and is required for the [Tab] and [Esc] keys to work.

MENU BACKGROUND background

For vesamenu.c32, sets the background image. The background can either be a color (see MENU COLOR) or the name of an image file, which should be 640×480 pixels and either in PNG or JPEG format.

MENU BEGIN [tagname]
MENU END

Begin/end a submenu. The entries between MENU BEGIN and MENU END form a submenu, which is marked with a > mark on the right hand of the screen. Submenus inherit the properties of their parent menus, but can override them, and can thus have their own backgrounds, master passwords, titles, timeouts, messages and so forth.

MENU GOTO tagname

(Only valid after a LABEL statement.)

This label will transfer to the named submenu instead of booting anything. To transfer to the top-level menu, specify “menu goto .top”.

MENU EXIT [tagname]

(Only valid after a label statement inside MENU BEGIN … MENU END)

Exit to the next higher menu, or, if tagname is specified, to the named menu.

MENU QUIT

(Only valid after a LABEL statement.)

This label quits the menu system.

WARNING: if MENU MASTER PASSWD or ALLOWOPTIONS 0 is set, this will still allow exiting to the CLI; however, a separate MENU PASSWD can of course be set for this label.

MENU START

(Only valid inside MENU BEGIN … MENU END)

Indicates that the menu system should start at the menu being defined instead of at the top-level menu.

INCLUDE filename [tagname]
MENU INCLUDE filename [tagname]

Include the contents of the configuration file filename at this point.

In the case of MENU INCLUDE, the included data is only seen by the menu system; the core syslinux code does not parse this command, so any labels defined in it are unavailable.

If a tagname is included, the whole file is considered to have been bracketed with a MENU BEGIN tagname … MENU END pair, and will therefore show up as a submenu.

MENU AUTOBOOT message

Replaces the message “Automatic boot in # second{,s}…”. The symbol # is replaced with the number of seconds remaining. The syntax ”{singular,[dual,]plural}” can be used to conjugate appropriately.

MENU TABMSG message

Replaces the message “Press [Tab] to edit options”.

MENU NOTABMSG message

Takes the place of the TABMSG message if option editing is disabled. Defaults to blank.

MENU PASSPROMPT message

Replaces the message “Password required”.

MENU COLOR element ansi foreground background shadow

Sets the color of element “element” to the specified color sequence:

screen          Rest of the screen
border          Border area
title           Title bar
unsel           Unselected menu item
hotkey          Unselected hotkey
sel             Selection bar
hotsel          Selected hotkey
disabled	Disabled menu item
scrollbar       Scroll bar
tabmsg          Press [Tab] message
cmdmark         Command line marker
cmdline         Command line
pwdborder       Password box border
pwdheader       Password box header
pwdentry        Password box contents
timeout_msg     Timeout message
timeout         Timeout counter
help		Help text
msgXX		Message (F-key) file attribute XX

… where XX is two hexadecimal digits (the “plain text” is 07).

“ansi” is a sequence of semicolon-separated ECMA-48 Set Graphics Rendition (<ESC>[m) sequences:

0     reset all attributes to their defaults
1     set bold
4     set underscore (simulated with color on a color display)
5     set blink
7     set reverse video
22    set normal intensity
24    underline off
25    blink off
27    reverse video off
30    set black foreground
31    set red foreground
32    set green foreground
33    set brown foreground
34    set blue foreground
35    set magenta foreground
36    set cyan foreground
37    set white foreground
38    set underscore on, set default foreground color
39    set underscore off, set default foreground color
40    set black background
41    set red background
42    set green background
43    set brown background
44    set blue background
45    set magenta background
46    set cyan background
47    set white background
49    set default background color

These are used (a) in text mode, and (b) on the serial console.

“foreground” and “background” are color codes in #AARRGGBB notation, where AA RR GG BB are hexadecimal digits for alpha (opacity), red, green and blue, respectively. #00000000 represents fully transparent, and #ffffffff represents opaque white.

“shadow” controls the handling of the graphical console text shadow. Permitted values are “none” (no shadowing), “std” or “standard” (standard shadowing - foreground pixels are raised), “all” (both background and foreground raised), and “rev” or “reverse” (background pixels are raised.)

If any field is set to “*” or omitted (at the end of the line) then that field is left unchanged.

The current defaults are:

menu color screen	37;40      #80ffffff #00000000 std
menu color border	30;44      #40000000 #00000000 std
menu color title	1;36;44    #c00090f0 #00000000 std
menu color unsel	37;44      #90ffffff #00000000 std
menu color hotkey	1;37;44    #ffffffff #00000000 std
menu color sel		7;37;40    #e0000000 #20ff8000 all
menu color hotsel	1;7;37;40  #e0400000 #20ff8000 all
menu color disabled	1;30;44    #60cccccc #00000000 std
menu color scrollbar	30;44      #40000000 #00000000 std
menu color tabmsg	31;40      #90ffff00 #00000000 std
menu color cmdmark	1;36;40    #c000ffff #00000000 std
menu color cmdline	37;40      #c0ffffff #00000000 std
menu color pwdborder	30;47      #80ffffff #20ffffff std
menu color pwdheader	31;47      #80ff8080 #20ffffff std
menu color pwdentry	30;47      #80ffffff #20ffffff std
menu color timeout_msg	37;40      #80ffffff #00000000 std
menu color timeout	1;37;40    #c0ffffff #00000000 std
menu color help		37;40      #c0ffffff #00000000 std
menu color msg07	37;40      #90ffffff #00000000 std
MENU MSGCOLOR fg_filter bg_filter shadow

Sets *all* the msgXX colors to a color scheme derived from the fg_filter and bg_filter values. Background color zero is always treated as transparent. The default corresponds to:

menu msgcolor #90ffffff #80ffffff std

This directive should come before any directive that customizes individual msgXX colors.

MENU WIDTH 80
MENU MARGIN 10
MENU PASSWORDMARGIN 3
MENU ROWS 12
MENU TABMSGROW 18
MENU CMDLINEROW 18
MENU ENDROW -1
MENU PASSWORDROW 11
MENU TIMEOUTROW 20
MENU HELPMSGROW 22
MENU HELPMSGENDROW -1
MENU HIDDENROW -2
MENU HSHIFT 0
MENU VSHIFT 0

These options control the layout of the menu on the screen. The values above are the defaults.

A negative value is relative to the calculated length of the screen (25 for text mode, 28 for VESA graphics mode.)

F1 textfile background
...
F12 textfile background

Displays full-screen help (also available at the command line.) The same control code sequences as in the command line interface are supported, although some are ignored.

Additionally, a second argument allows a different background image (see MENU BACKGROUND for supported formats) to be displayed.

The menu system honours the TIMEOUT command; if TIMEOUT is specified it will execute the ONTIMEOUT command if one exists, otherwise it will pick the default menu option.

Normally, the user can press [Tab] to edit the menu entry, and [Esc] to return to the SYSLINUX command line. However, if the configuration file specifies ALLOWOPTIONS 0, these keys will be disabled, and if MENU MASTER PASSWD is set, they require the master password.

The simple menu system supports serial console, using the normal SERIAL directive. However, it can be quite slow over a slow serial link; you probably want to set your baudrate to 38400 or higher if possible. It requires a Linux/VT220/ANSI-compatible terminal on the other end.

Using an alternate configuration file

It is also possible to load a secondary configuration file, to get to another menu. To do that, invoke menu.c32 with the name of the secondary configuration file.

LABEL othermenu
	MENU LABEL Another Menu
	KERNEL menu.c32
	APPEND othermenu.conf

If you specify more than one file, they will all be read, in the order specified. The dummy filename ~ (tilde) is replaced with the filename of the main configuration file.

# The file graphics.conf contains common color and layout commands for
# all menus.
LABEL othermenu
	MENU LABEL Another Menu
	KERNEL vesamenu.c32
	APPEND graphics.conf othermenu.conf
# Return to the main menu
LABEL mainmenu
	MENU LABEL Return to Main Menu
	KERNEL vesamenu.c32
	APPEND graphics.conf ~

See also the MENU INCLUDE directive above.