cwd's questions

I am setting up a dual booting headless Linux / Windows machine. I mostly want the machine to always boot up to Ubuntu, except for occasionally when I need to test something in windows.

I've installed Windows and Ubuntu, and currently it boots up to Ubuntu every time. I would like to be able to tell it to boot to Windows on the next boot only and then when I restart from Windows have the system return to booting Ubuntu.

I found Grub Legacy - section 4.3.1 - Booting once-only but I am using Ubuntu 14.04 server which has the newer version of grub. From what I've read, I need to make some changes to /etc/default/grub and use sudo grub-set-default when I want to boot to Windows.

I think those changes start with adding this to /etc/default/grub:

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=false

Anytime changes are made to /etc/default/grub I know that I need to then run
sudo update-grub and which results in:

Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.13.0-43-generic
Found initrd image: /boot/initrd.img-3.13.0-43-generic
Found linux image: /boot/vmlinuz-3.13.0-32-generic
Found initrd image: /boot/initrd.img-3.13.0-32-generic
Found memtest86+ image: /boot/memtest86+.elf
Found memtest86+ image: /boot/memtest86+.bin
Found Windows 7 (loader) on /dev/sda1
done

Since Windows is the 7th option in that list I believe I would run sudo grub-set-default 6 (0 based counting) - is this correct and is there a different method to get a numbered list of boot choices after the system is already booted?

Also, are the lines in /etc/default/grub sufficient to achieve this behavior or do I need to add additional configuration?

During Ubuntu installation I enjoyed using the "Configure the Network" step:

I always assumed that there was some dpkg-reconfigure command that would re-run this, and that if I ever wanted to use it I would just need to search for it. However, when I actually went out and looked for a way to access something like this I couldn't find anything, and from what I've been reading it looks like there may be no such thing after all. Is that right?

To clarify, I'm not having a trouble configuring my network adapter (so no need for a response detailing how to accomplish that.) I'm just curious if Ubuntu server has a CLI menu-interface like the one that is used during installation - and if so, how does one access it?

On Ubuntu 12.04 is /etc/skel/ the correct place to put extra files for new users?

In the Linux Administration Handbook it mentions files from /usr/local/lib/skel which doesn't seem like an Ubuntu-esque path, nor does it exist on my fresh install of 12.04 server.

I'm just curious if there is anything like a conf.d directory for /etc/skel/ or a /usr/local/skel and where that would be in the documentation.

I know you can specify which skeleton to use with the SKEL variable with adduser - just curious what the "correct" way to go about editing the skeletons is with this part of system administration is - if there is an agree'd upon one.

I'm running the lastest Ubuntu 12.04 AMI (ami-a29943cb) from Canonical on Amazon EC2 and quite often when I log in I get the message:

*** /dev/xvda1 will be checked for errors at next reboot ***

I have read a bunch of documentation on this and seem to understand that every so many reboots (around 37 see Mount count / Maximum mount count below) Ubuntu wants to check a disk for errors. I can see that by using dumpe2fs -h /dev/xvda1 (reference) to get information such as:

Last mounted on:          /
Filesystem UUID:          1ad27d06-4ecf-493d-bb19-4710c3caf924
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              524288
Block count:              2097152
Reserved block count:     104857
Free blocks:              1778055
Free inodes:              482659
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      511
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Flex block group size:    16
Filesystem created:       Tue Apr 24 03:07:48 2012
Last mount time:          Thu Nov  8 03:17:58 2012
Last write time:          Tue Apr 24 03:08:52 2012
Mount count:              3
Maximum mount count:      37
Last checked:             Tue Apr 24 03:07:48 2012
Check interval:           15552000 (6 months)
Next check after:         Sun Oct 21 03:07:48 2012
Lifetime writes:          2454 MB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:           256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      0a25e04c-6169-4d68-bfa6-a1acd8e39632
Journal backup:           inode blocks
Journal features:         journal_incompat_revoke
Journal size:             128M
Journal length:           32768
Journal sequence:         0x0000158b
Journal start:            1

I've tried these things to get rid of the message and usually the badblocks is what does it for me:

Run this command and reboot:

sudo touch /forcefsck

Run badblocks to check the disk:

badblocks /dev/sda1

Edit /etc/fstab and change the last "0" which is the fs_passno column accordingly and then reboot:

The root filesystem should be specified with a fs_passno of 1, and other filesystems should have a fs_passno of 2.

I don't understand:

1. If this is a virtual drive shouldn't it be less prone to errors?
2. Was the image created with one of the flags set? If not what is triggering it?
3. Why is fs_passno set to 0 on Amazon EC2 Ubuntu images? This is not the first one that is like this.

Is reboot the same as init 6 for ubuntu?

I'm running Ubuntu 12.04 on Amazon EC2. When ssh'ed into the box I can type runlevel and I get:

N 2

Looking at man reboot I see that:

When called with --force or when in runlevel 0 or 6, this tool invokes the reboot(2) system call itself and directly reboots the system. Otherwise this simply invokes the shutdown(8) tool with the appropriate arguments.

If I read man shutdown 8 I see:

shutdown arranges for the system to be brought down in a safe way. All logged-in users are notified that the system is going down and, within the last five minutes of TIME, new logins are prevented.

My basic understanding about the difference between reboot and init 6 is:

• On other distros and perhaps older distros reboot would just unmount the disks and basically flick the power switch without running any shutdown scripts
• init 6 will run all of the shutdown scripts in /etc/init/rc.* as it reduces system's runlevel
• On newer versions of Ubuntu the reboot command without --force or -f will run the shutdown command which does would basically do the same thing as init 6
• It's probably better to get in the habit of using init 6 instead of reboot as it is safer and would work better cross-distro, but the default behavior of reboot has been changed to try and prevent errors / dataloss if someone does use it.

Is that about right? If not, what am I missing?

In the Linux / Unix administration handbook it mentions that you can edit the /etc/inittab file to change the run level. I don't have that file on 10.04. I Googled this and found a tip saying that file had been replaced with /etc/event.d/rc-default - however I don't have that file on my system either.

Have these been deleted or does 10.04 deal with run levels differently?

How can I set HISTSIZE for all users on Ubuntu 10.04?

I've tried adding the following lines to both /etc/profile and /etc/bash.bashrc. I'm not sure I understand the difference between the two files but I really think either one should work on an interactive shell, right?

export HISTCONTROL=erasedups:ignorespace
export HISTSIZE=5000
shopt -s histappend

For some reason this won't work though. I have added the lines to the bottom, logged out, logged back in, and typed echo $HISTSIZE and I get "1000"?

What am I doing wrong?

On 10.04 Lucid, how can I add a script to run at startup as another user?

Will I add a script someplace like /etc/init.d/myscript ? Or is it better to put it in the cron file for root as @reboot and the exec command? Or something completely different?

I'm new to this (sorry) but I have been googling without much luck. Links to tutorials would be fine as well, I'm just feeling a little lost not knowing where to start...

I've seen several guides online which describe downloading and building Nagios on Ubuntu servers. Is there also an aptitude package I could use to install Nagios 3?