CentOS 7.0 - man page for syslinux (centos section 1)

Linux & Unix Commands - Search Man Pages

Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)

SYSLINUX(1)									      SYSLINUX(1)

       syslinux - install the SYSLINUX bootloader on a FAT filesystem

       syslinux [OPTIONS] device

       Syslinux is a boot loader for the Linux operating system which operates off an MS-DOS/Win-
       dows FAT filesystem. It is intended to simplify first-time installation of Linux, and  for
       creation of rescue and other special-purpose boot disks.

       In order to create a bootable Linux floppy using Syslinux, prepare a normal MS-DOS format-
       ted floppy. Copy one or more Linux kernel files to it, then execute the command:

	      syslinux --install /dev/fd0

       This will alter the boot sector on the disk and copy a file  named  ldlinux.sys	into  its
       root directory.

       On boot time, by default, the kernel will be loaded from the image named LINUX on the boot
       floppy.	This default can be changed, see the section on the syslinux configuration file.

       If the Shift or Alt keys are held down during boot, or the Caps or Scroll locks	are  set,
       syslinux  will  display	a  lilo(8) -style "boot:" prompt. The user can then type a kernel
       file name followed by any kernel parameters. The SYSLINUX bootloader does not need to know
       about the kernel file in advance; all that is required is that it is a file located in the
       root directory on the disk.

       Syslinux supports the loading of initial ramdisks (initrd) and the bzImage kernel format.

       -i, --install
	      Install SYSLINUX on a new medium, overwriting any previously installed bootloader.

       -U, --update
	      Install SYSLINUX on a new medium if and only if a version of  SYSLINUX  is  already

       -s, --stupid
	      Install  a  "safe,  slow	and stupid" version of SYSLINUX. This version may work on
	      some very buggy BIOSes on which SYSLINUX would  otherwise  fail.	 If  you  find	a
	      machine on which the -s option is required to make it boot reliably, please send as
	      much info about your machine as you can, and include the failure mode.

       -f, --force
	      Force install even if it appears unsafe.

       -r, --raid
	      RAID mode.  If boot fails, tell the BIOS to  boot  the  next  device  in	the  boot
	      sequence	(usually  the  next hard disk) instead of stopping with an error message.
	      This is useful for RAID-1 booting.

       -d, --directory subdirectory
	      Install the SYSLINUX control files in a subdirectory with the specified name (rela-
	      tive to the root directory on the device).

       -t, --offset offset
	      Indicates that the filesystem is at an offset from the base of the device or file.

       --once command
	      Declare a boot command to be tried on the first boot only.

       -O, --clear-once
	      Clear the boot-once command.

       -H, --heads head-count
	      Override the detected number of heads for the geometry.

       -S, --sectors sector-count
	      Override the detected number of sectors for the geometry.

       -z, --zipdrive
	      Assume zipdrive geometry (--heads 64 --sectors 32).

	      Reset auxilliary data.

       -M, --menu-save
	      Set the label to select as default on the next boot.

   Configuration file
       All  the  configurable  defaults  in SYSLINUX can be changed by putting a file called sys-
       linux.cfg in the install directory of the boot disk. This is a text file in either UNIX or
       DOS  format,  containing  one or more of the following items (case is insensitive for key-

       This list is out of date.

       In the configuration file blank lines and comment lines beginning with a hash mark (#) are

       default kernel [ options ... ]
	      Sets the default command line. If syslinux boots automatically, it will act just as
	      if the entries after "default" had been typed in at the "boot:" prompt.

	      If no DEFAULT or UI statement is	found,	or  the  configuration	file  is  missing
	      entirely,  SYSLINUX drops to the boot: prompt with an error message (if NOESCAPE is
	      set, it stops with a "boot failed" message; this is also the case for  PXELINUX  if
	      the configuration file is not found.)

       NOTE: Until SYSLINUX 3.85, if no configuration file is present, or no
	      "default" entry is present in the configuration file, the default is "linux auto".

       Even earlier versions of SYSLINUX used to automatically
	      append  the string "auto" to whatever the user specified using the DEFAULT command.
	      As of version 1.54, this is no longer true, as it  caused  problems  when  using	a
	      shell as a substitute for "init."  You may want to include this option manually.

       append options ...
	      Add  one or more options to the kernel command line. These are added both for auto-
	      matic and manual boots. The options are added at the very beginning of  the  kernel
	      command  line,  usually  permitting  explicitly  entered kernel options to override
	      them. This is the equivalent of the lilo(8)
	       "append" option.

       label label
	 kernel image
	 append options ...
	      Indicates that if label is entered as the kernel to boot, syslinux  should  instead
	      boot  image,  and the specified "append" options should be used instead of the ones
	      specified in the global section of the file (before the first "label" command.) The
	      default  for image is the same as label, and if no "append" is given the default is
	      to use the global entry (if any).  Use "append -" to use no options at all.  Up  to
	      128 "label" entries are permitted.

		     The  "image" doesn't have to be a Linux kernel; it can be a boot sector or a
		     COMBOOT file (see below.)

       implicit flag_val
	      If flag_val is 0, do not load a kernel image unless it has been explicitly named in
	      a "label" statement.  The default is 1.

       timeout timeout
	      Indicates  how  long  to wait at the "boot:" prompt until booting automatically, in
	      units of 1/10 s. The timeout is cancelled as soon as the user types anything on the
	      keyboard, the assumption being that the user will complete the command line already
	      begun. A timeout of zero will disable the timeout  completely,  this  is	also  the
	      default.	The  maximum possible timeout value is 35996; corresponding to just below
	      one hour.

       serial port [ baudrate ]
	      Enables a serial port to act as the console. "port" is a number (0 =  /dev/ttyS0	=
	      COM1,  etc.);  if  "baudrate"  is omitted, the baud rate defaults to 9600 bps.  The
	      serial parameters are hardcoded to be 8 bits, no parity, 1 stop bit.

	      For this directive to be guaranteed to work properly, it should be the first direc-
	      tive in the configuration file.

       font filename
	      Load a font in .psf format before displaying any output (except the copyright line,
	      which is output as ldlinux.sys itself is loaded.) syslinux only loads the font onto
	      the video card; if the .psf file contains a Unicode table it is ignored.	This only
	      works on EGA and VGA cards; hopefully it should do nothing on others.

       kbdmap keymap
	      Install a simple keyboard map. The keyboard remapper used is  very  simplistic  (it
	      simply  remaps  the  keycodes received from the BIOS, which means that only the key
	      combinations relevant in the default layout  -  usually  U.S.   English  -  can  be
	      mapped)  but  should at least help people with AZERTY keyboard layout and the loca-
	      tions of = and , (two special characters used heavily on the Linux  kernel  command

	      The included program keytab-lilo.pl(8) from the lilo(8)
	       distribution can be used to create such keymaps.

       display filename
	      Displays the indicated file on the screen at boot time (before the boot: prompt, if
	      displayed). Please see the section below on DISPLAY files. If the file is  missing,
	      this option is simply ignored.

       prompt flag_val
	      If  flag_val  is	0,  display  the  "boot:"  prompt only if the Shift or Alt key is
	      pressed, or Caps Lock or Scroll lock is set (this is the default).  If flag_val  is
	      1, always display the "boot:" prompt.

       f1 filename
       f2 filename
       f9 filename
       f10 filename
       f11 filename
       f12 filename
	      Displays	the  indicated	file  on the screen when a function key is pressed at the
	      "boot:" prompt. This can be used to implement pre-boot online help (presumably  for
	      the kernel command line options.)

	      When  using  the	serial console, press <Ctrl-F><digit> to get to the help screens,
	      e.g. <Ctrl-F>2 to get to the f2 screen.  For  f10-f12,  hit  <Ctrl-F>A,  <Ctrl-F>B,
	      <Ctrl-F>C.   For	compatiblity  with  earlier  versions, f10 can also be entered as

   Display file format
       DISPLAY and function-key help files are text files in either DOS or UNIX format	(with  or
       without <CR>). In addition, the following special codes are interpreted:

       <FF> = <Ctrl-L> = ASCII 12
	      Clear the screen, home the cursor.  Note that the screen is filled with the current
	      display color.

       <SI><bg><fg>, <SI> = <Ctrl-O> = ASCII 15
	      Set the display colors to the specified background  and  foreground  colors,  where
	      <bg> and <fg> are hex digits, corresponding to the standard PC display attributes:

	      0 = black 	 8 = dark grey
	      1 = dark blue	 9 = bright blue
	      2 = dark green	 a = bright green
	      3 = dark cyan	 b = bright cyan
	      4 = dark red	 c = bright red
	      5 = dark purple	 d = bright purple
	      6 = brown 	 e = yellow
	      7 = light grey	 f = white

	      Picking  a  bright color (8-f) for the background results in the corresponding dark
	      color (0-7), with the foreground flashing.

	      colors are not visible over the serial console.

       <CAN>filename<newline>, <CAN> = <Ctrl-X> = ASCII 24
	      If a VGA display is present, enter graphics mode and display the	graphic  included
	      in  the  specified  file.   The  file  format is an ad hoc format called LSS16; the
	      included Perl program "ppmtolss16" can be used to produce these images.  This  Perl
	      program also includes the file format specification.

	      The  image  is displayed in 640x480 16-color mode.  Once in graphics mode, the dis-
	      play attributes (set by <SI> code sequences) work slightly differently:  the  back-
	      ground  color  is ignored, and the foreground colors are the 16 colors specified in
	      the image file.  For that reason, ppmtolss16 allows you  to  specify  that  certain
	      colors should be assigned to specific color indicies.

	      Color  indicies  0 and 7, in particular, should be chosen with care: 0 is the back-
	      ground color, and 7 is the color used for the text printed by SYSLINUX itself.

       <EM>, <EM> = <Ctrl-U> = ASCII 25
	      If we are currently in graphics mode, return to text mode.

       <DLE>..<ETB>, <Ctrl-P>..<Ctrl-W> = ASCII 16-23
	      These codes can be used to select which modes to print a certain part of	the  mes-
	      sage  file  in.	Each  of  these control characters select a specific set of modes
	      (text screen, graphics screen, serial port) for which the output is  actually  dis-

	      Character 		      Text    Graph   Serial
	      <DLE> = <Ctrl-P> = ASCII 16     No      No      No
	      <DC1> = <Ctrl-Q> = ASCII 17     Yes     No      No
	      <DC2> = <Ctrl-R> = ASCII 18     No      Yes     No
	      <DC3> = <Ctrl-S> = ASCII 19     Yes     Yes     No
	      <DC4> = <Ctrl-T> = ASCII 20     No      No      Yes
	      <NAK> = <Ctrl-U> = ASCII 21     Yes     No      Yes
	      <SYN> = <Ctrl-V> = ASCII 22     No      Yes     Yes
	      <ETB> = <Ctrl-W> = ASCII 23     Yes     Yes     Yes

	      For example:
	      <DC1>Text mode<DC2>Graphics mode<DC4>Serial port<ETB>
	       ... will actually print out which mode the console is in!

       <SUB> = <Ctrl-Z> = ASCII 26
	      End of file (DOS convention).

   Comboot Images and other operating systems
       This version of syslinux supports chain loading of other operating systems (such as MS-DOS
       and its derivatives, including Windows 95/98), as well as  COMBOOT-style  standalone  exe-
       cutables (a subset of DOS .COM files; see separate section below.)

       Chain  loading  requires the boot sector of the foreign operating system to be stored in a
       file in the root directory of the filesystem.  Because neither Linux kernels, boot  sector
       images,	nor  COMBOOT  files  have  reliable magic numbers, syslinux will look at the file
       extension. The following extensions are recognised:

       none or other	Linux kernel image
       CBT		COMBOOT image (not runnable from DOS)
       BSS		Boot sector (DOS superblock will be patched in)
       BS		Boot sector
       COM		COMBOOT image (runnable from DOS)

       For filenames given on the command line, syslinux will  search  for  the  file  by  adding
       extensions in the order listed above if the plain filename is not found. Filenames in KER-
       NEL statements must be fully qualified.

       A COMBOOT file is a standalone executable in  DOS  .COM	format.  They  can,  among  other
       things, be produced by the Etherboot package by Markus Gutschke and Ken Yap. The following
       requirements apply for these files to be sufficiently "standalone" for syslinux to be able
       to load and run them:

       o      The program must not execute any DOS calls (since there is no DOS), although it may
	      call the BIOS. The only exception is that the program may execute INT  20h  (Termi-
	      nate  Program)  to  return  to  the  syslinux  prompt. Note especially that INT 21h
	      AH=4Ch, INT 21h AH=31h or INT 27h are not supported.

       o      Only the fields pspInt20 at offset 00h, pspNextParagraph at offset 02h and  pspCom-
	      mandTail	at  offset 80h (contains the arguments from the syslinux command line) in
	      the PSP are supported. All other fields will contain zero.

       o      The program must not modify any main memory outside its 64K segment if  it  returns
	      to syslinux via INT 20h.

       Syslinux currently doesn't provide any form of API for the use of COMBOOT files.  If there
       is need, a future version may contain an INT interface to some syslinux functions;  please
       contact me if you have a need or ideas for such an API.

   Novice protection
       Syslinux  will  attempt	to  detect  if the user is trying to boot on a 286 or lower class
       machine, or a machine with less than 608K of low ("DOS") RAM (which means the  Linux  boot
       sequence  cannot  complete).  If so, a message is displayed and the boot sequence aborted.
       Holding down the Ctrl key while booting disables this feature.

       The compile time and date of a specific syslinux version can be obtained by the	DOS  com-
       mand  "type  ldlinux.sys".  This  is  also used as the signature for the LDLINUX.SYS file,
       which must match the boot sector

       Any file that syslinux uses can be marked hidden, system or readonly if so is  convenient;
       syslinux ignores all file attributes.  The SYSLINUX installed automatically sets the read-
       only attribute on LDLINUX.SYS.

   Bootable CD-ROMs
       SYSLINUX can be used to create bootdisk images for El Torito-compatible bootable  CD-ROMs.
       However, it appears that many BIOSes are very buggy when it comes to booting CD-ROMs. Some
       users have reported that the following steps are  helpful  in  making  a  CD-ROM  that  is
       bootable on the largest possible number of machines:

       o      Use the -s (safe, slow and stupid) option to SYSLINUX

       o      Put  the	boot image as close to the beginning of the ISO 9660 filesystem as possi-

       A CD-ROM is so much faster than a floppy that the -s option shouldn't matter from a  speed

       Of  course,  you  probably  want  to  use  ISOLINUX  instead.   See the documentation file

   Booting from a FAT partition on a hard disk
       SYSLINUX can boot from a FAT filesystem partition on a hard disk  (including  FAT32).  The
       installation  procedure	is  identical to the procedure for installing it on a floppy, and
       should work under either DOS or Linux. To boot from a  partition,  SYSLINUX  needs  to  be
       launched  from  a Master Boot Record or another boot loader, just like DOS itself would. A
       sample master boot sector (mbr.bin) is included with SYSLINUX.

       I would appreciate hearing of any problems you have with SYSLINUX.  I would also  like  to
       hear from you if you have successfully used SYSLINUX, especially if you are using it for a

       If you are reporting problems, please include all possible information about  your  system
       and  your BIOS; the vast majority of all problems reported turn out to be BIOS or hardware
       bugs, and I need as much information as possible in order to diagnose the problems.

       There is a mailing list for discussion among SYSLINUX users and for announcements  of  new
       and test versions. To join, send a message to majordomo@linux.kernel.org with the line:

       subscribe syslinux

       in the body of the message. The submission address is syslinux@linux.kernel.org.

       lilo(8), keytab-lilo.pl(8), fdisk(8), mkfs(8), superformat(1).

       This  manual page is a modified version of the original syslinux documentation by H. Peter
       Anvin  <hpa@zytor.com>.	The  conversion  to  a	manpage   was	made   by   Arthur   Korn

SYSLINUX				   19 July 2010 			      SYSLINUX(1)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums

All times are GMT -4. The time now is 08:55 PM.

Unix & Linux Forums Content Copyright©1993-2018. All Rights Reserved.
Show Password

Not a Forum Member?
Forgot Password?