grub.cfg read only

[scutiform]

I have installed Ubuntu 9.10 as a dual boot with 9.04. I would like to edit the grub config file to get rid of all the superfluous menu entries and put the 9.04 entry before the 9.10 one. With 9.04 I can edit menu.lst as sudo gedit menu.lst and save it. When I sudo gedit grub.cfg I am no allowed to save the file. I get "You are trying to save to a read only disk" error. How can I get the grub folder to be R/W just for the editing session?

[devils casper]

You should not edit grub.cfg file because it is a simple conf file generated by GRUB2 scripts. Whatever you change in it will be gone on next update.

If you want to change Menu entries, edit /etc/grub.d/10_linux file. Make sure to execute update-grub2 file after editing it.

[jmadero]

thanks casper, I was curious about this one as well....I'm not too keen on this new Grub, I hear it's a lot better but I feel like they just did a massive change without giving people enough time to slowly adjust. This makes a lot of sense though

[scutiform]

Had a look at /etc/grub.d/10-linux and it doesn't seem to be relevant to the menu list. I am sending part of the file as a sample (The original file is 3 pages long)

grub.cfg looked the same as the old menu.lst

prefix=/usr
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
. ${libdir}/grub/grub-mkconfig_lib

if [ "x${GRUB_DISTRIBUTOR}" = "x" ] ; then
OS=GNU/Linux
else
OS="${GRUB_DISTRIBUTOR}"
fi

# loop-AES arranges things so that /dev/loop/X can be our root device, but
# the initrds that Linux uses don't like that.
case ${GRUB_DEVICE} in
/dev/loop/*|/dev/loop[0-9])
GRUB_DEVICE=`losetup ${GRUB_DEVICE} | sed -e "s/^[^(]*(\([^)]\+\)).*/\1/"`
# We can't cope with devices loop-mounted from files here.
case ${GRUB_DEVICE} in
/dev/*) ;;
*) exit 0 ;;
esac
;;
esac

if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
|| ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
|| [ "`grub-probe -t abstraction --device ${GRUB_DEVICE} | sed -e 's,.*\(lvm\).*,\1,'`" = "lvm" ] ; then
LINUX_ROOT_DEVICE=${GRUB_DEVICE}
else
LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
fi

# add crashkernel option if we have the required tools
if [ -x "/usr/bin/makedumpfile" ] && [ -x "/sbin/kexec" ]; then
GRUB_CMDLINE_EXTRA="$GRUB_CMDLINE_EXTRA crashkernel=384M-2G:64M,2G-:128M"
fi

linux_entry ()
{
cat << EOF
menuentry "$1" {
recordfail=1
if [ -n \${have_grubenv} ]; then save_env recordfail; fi
EOF
if [ "x$3" = "xquiet" ]; then
cat << EOF
set quiet=1
EOF
fi
save_default_entry | sed -e "s/^/\t/"
prepare_grub_to_access_device ${GRUB_DEVICE_BOOT} | sed -e "s/^/\t/"
cat << EOF
linux ${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro $2
EOF
if test -n "${initrd}" ; then
cat << EOF
initrd ${rel_dirname}/${initrd}
EOF
fi
cat << EOF
}
EOF
}

list=`for i in /boot/vmlinu[xz]-* /vmlinu[xz]-* ; do
if grub_file_is_not_garbage "$i" ; then echo -n "$i " ; fi
done`

while [ "x$list" != "x" ] ; do
linux=`version_find_latest $list`
echo "Found linux image: $linux" >&2
basename=`basename $linux`
dirname=`dirname $linux`
rel_dirname=`make_system_path_relative_to_its_root $dirname`
version=`echo $basename | sed -e "s,^[^0-9]*-,,g"`
alt_version=`echo $version | sed -e "s,\.old$,,g"`
linux_root_device_thisversion="${LINUX_ROOT_DEVICE }"

initrd=
for i in "initrd.img-${version}" "initrd-${version}.img" \
"initrd-${version}" "initrd.img-${alt_version}" \
"initrd-${alt_version}.img" "initrd-${alt_version}"; do
if test -e "${dirname}/${i}" ; then
initrd="$i"
break
fi
done
if test -n "${initrd}" ; then
echo "Found initrd image: ${dirname}/${initrd}" >&2
else
# "UUID=" magic is parsed by initrds. Since there's no initrd, it can't work here.
linux_root_device_thisversion=${GRUB_DEVICE}
fi

linux_entry "${OS}, Linux ${version}" \
"${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_EXTRA} ${GRUB_CMDLINE_LINUX_DEFAULT}" \
quiet
if [ "x${GRUB_DISABLE_LINUX_RECOVERY}" != "xtrue" ]; then
linux_entry "${OS}, Linux ${version} (recovery mode)" \
"single ${GRUB_CMDLINE_LINUX}"
-------------------------------------------------------------

[oz]

Hi, scutiforum

I'm not sure that it will help any, but there is a nice wiki page on the Ubuntu website that might offer up some clues that can help:

https://wiki.ubuntu.com/Grub2

On my Arch box, I have to edit the grub.cfg file directly, but it's my understanding that it's done differently under Ubuntu. Hope the wiki page helps.

[scutiform]

I followed the info from Outcast-Aussie and 9.04 is now the default version to load. Thanks for that. I would still like to find how to edit the list. I am transfering files, settings etc from 9.04 to 9.10, but the last time I ran 9.10, I had so many problems, I un-installed it and re-installed 9.04. I'm just giving 9.10 another chance. The Grub loader looks so messy. The old menu.lst file was easy to tidy up.

[scutiform]

Thanks, ozar. I read the wiki and have decided I'll keep the messy menu.

Why fix something if it isn't broke? I love the fact that Linux is always evolving and improving, but I would like the chance to not install an update to a program, or roll-back to a previous version if I wanted to

[oz]

Yup, GRUB2 definitely seems more complex than the legacy version was, but I'm hoping that it will be simplified as it matures a bit. For now, it's still rather experimental in nature although it has been working pretty well on my box for the last 12 months, or so.