On Tuesday 25 August 2009 11:54:21 pm David C. Rankin wrote:
> On Tuesday 25 August 2009 09:51:50 pm Sven-Hendrik Haase wrote:
> > There are multiple ways:
> > You can put "default 2" at the very top of your menu.lst which will
> > always select the 2nd entry (0-based) by default.
> > Another and maybe more modern way to do it is to add "default saved"
> > at the top and then add "savedefault" below each individual entry. This
> > way, Grub will always select the last selected entry.
>
> Sven,
>
> Thanks, sorry, I know all that. I'm looking for a quick command that does
> NOT alter the menu.lst file, but sets some type of flag that tells grub do
> NOT boot the default entry, instead, boot entry 5.
>
> I know there is something in kde4 that will do it because when you
> hold-down the Restart option, you can set the next OS you want to boot if
> you have more than 1 entry in menu.lst. Ever hear of anything like that
> for Arch?
>
> With grubonce, you just enter grubonce (without arguments) and it returns
> a list of what is in your menu.lst file:
>
> [23:52 dcrgx/home/david/scripts/file] # grubonce
> 0: openSUSE 11.0 - 2.6.25.20-0.5
> 1: Failsafe -- openSUSE 11.0 - 2.6.25.20-0.5
> 2: openSUSE 11.1 - 2.6.27.19-3.2 (/dev/sdb1)
> 3: Windows
>
> Then all you have to do is issue the command:
>
> # grubonce 2
>
> and you will boot suse 11.1 next time. That's what I'm looking for. I'll
> keep digging.
>
A, hah!
Should have checked in the first place. suse just uses a script. Here it is:
#!/usr/bin/perl
# Keep this sort of configurable for the future.
$GRUBDIR="/boot/grub";
# Parse the menu file, and see if we can get a match for a maybe given arg.
open(MENU, "<$GRUBDIR/menu.lst") || die "no menu.lst in $GRUBDIR";
$gotit = 0;
$titleno = -1;
$global_default = undef;
while(<MENU>) {
m,\s*default\s+(.+), && $titleno == -1 && ($global_default = $1);
next unless m,\s*title\s+(.*),i;
$title_name = $1;
$titleno++;
if (@ARGV > 0) {
# Argument may be entirely numerical, in which case it is an index,
# or a perl RE that leads to the first title matching.
if (( $ARGV[0] =~ m,^[0-9]+$, && $titleno eq $ARGV[0] ) ||
( $ARGV[0] !~ m,^[0-9]+$, && $title_name =~ m,$ARGV[0],i) ) {
$gotit = 1;
last;
}
} else {
print "$titleno: $title_name\n";
}
}
close(MENU);
print "Warning: you haven't set a global default!\n" if
!defined($global_default);
# Without a command line argument, we have now listet the titles and are done.
exit 0 if @ARGV < 1;
# Else the user wants to write the default file. We have better found a match!
if ($gotit > 0) {
print "Warning: your global default is 'saved'; changing default
permanently!"
if $global_default eq "saved";
print "Using entry #$titleno: $title_name\n";
# set the magic one-time flag
$titleno |= 0x4000;
open(DEFFILE, ">$GRUBDIR/default") ||
die "Cannot open default file for writing";
$buf = $titleno . "\0" . "\n" x 9;
syswrite(DEFFILE, $buf, 10);
close(DEFFILE);
exit 0;
} else {
print $ARGV[0] . " not found in $GRUBDIR/menu.lst\n";
exit 1;
}
--
David C. Rankin, J.D.,P.E.
Rankin Law Firm, PLLC
510 Ochiltree Street
Nacogdoches, Texas 75961
Telephone: (936) 715-9333
Facsimile: (936) 715-9339
www.rankinlawfirm.com
