1. Edit your /etc/inittab file and add this line:
   • S0:12345:respawn:/sbin/agetty -L 9600 ttyS0 vt102
2. Execute the following command:
   • telinit q && telinit u
3. Your primary console (ttyS0) should magically appear on the serial console!

So what just happened? The /etc/inittab file is read by the init system at boot. If you added the line from step 1 and simply rebooted, you would have your console show up on the serial port right away. We told init to re-read the /etc/inittab file (telinit q) and then to re-execute itself (telinit u) while preserving the init state. Since the only change was the location of ttyS0, the console was redirected, but the system continued to run as though nothing else changed.

The reason we used the && method was because we may loose our console before we get a chance to execute telinit u. This way both commands are run and init is always executed after re-reading its config.

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Test it:

# cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
1
#

Set it to 0 for ping replies:

# echo "0" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
# cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts
0
#

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If you have a file that begins with a hyphen (one of these: -) you’ll have a tough time removing it unless you remember something simple from Command Line 101. In most CLI environments, your shell has two ways to access a file: relative path and absolute path.

See, all I had to do was type that and 90% of you just went “Durr!” and removed your file.

For the rest of you, just refer to the file by it’s full path. Example:

/tmp$ ls -la|grep ^\-
-rw-r--r-- 1 bob bob 0 2009-10-28 12:50 -somefile

Oh look, I have a file in /tmp called -somefile. What ever shall I do to remove it?

/tmp$ rm -somefile
rm: invalid option -- s
Try `rm ./-somefile' to remove the file `-somefile'.
Try `rm --help' for more information.

Oh my! That didn’t work at all! The rm command thinks I’m passing it a flag called -somefile. Conveniently, rm knows I’m not very bright and tells me how to remove it!

/tmp$ rm ./-somefile
/tmp$

Well blow me down! Alternately, you can refer to the file with the full path:

/tmp$ rm /tmp/-somefile
/tmp$

The key is to remember that the shell knows where you are, but doesn’t know what you want. If you imply that you want to delete something, the shell does it’s best guess. In this case, it guesses wrong because rm command flags take precedence over arguments. If you are explicit in what you want, the shell does not have to guess.

Of course, being fully explicit means issuing the full command for rm:

/bin/rm /tmp/-somefile

But you have to know where rm lives. You can guess, or you can find it with which:

$ which rm
/bin/rm

But how do you know where which is?

``/usr/bin/which which` rm` /tmp/-somefile

Ok, that’s dumb. Go remove your file.

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Common errors are:

Target filesystem doesn’t have sbin/init
BusyBox v.1.1.3
/bin/sh: can’t access tty; job control turned off
(initramfs)

or

mount: Mounting /root/dev on /dev/.static/dev failed: No such file or directory
Done.
Target filesystem doesn’t have /sbin/init

or

Mounting root file system…
Running /scripts/local-top…Done.
Running /scripts/local-premount…Done.
kjournald starting. Commit interval 5 seconds.
Running /scripts/log-bottom…Done.
Running /scripts/init-bottom…
Mounting /root/dev on /dev/.static/dev failed: No such file or directory…Done.
Mounting /sys on /root/sys filed: No such file or directory
Mounting /proc on /root/proc filed: No such file or directory
Target filesystem doesn’t have /sbin/init

A common reason for this is simple. Your GRUB menu is messed up and you swear you didn’t touch it!

There is a bug somewhere in Debian that changes your filesystem from /dev/sd<something> to /dev/sd<something else>. Of course changing that will make the system mount root from the wrong partition and BOOM! No boot for you.

In my case it constantly changes my boot partition from /dev/sda1 to /dev/sdb1 which is really annoying. If I don’t update /boot/grub/menu.lst before I reboot, my system will not come back.

Lucky for you Debian has BusyBox and initramfs with the 2.6 kernel.

You will have to be on the console for this, but here is how to get up and running:

• Boot up your broken system.
• (initramfs) is actually a prompt, so:
  • (initramfs) cd /
• (initramfs) mkdir /mnt Make a directory in the RAM filesystem.
• (initramfs) mount /dev/sda1 /mnt Mount your REAL root partition there.
• (initramfs) vi /mnt/boot/grub/menu.lst Edit your menu.lst file to load the correct partition (toward the bottom)
• (initramfs) reboot

In my most recent case, the line:

kernel /boot/vmlinuz-2.6.18-4-686 root=/dev/sda1 ro

Was changed to

kernel /boot/vmlinuz-2.6.18-4-686 root=/dev/sdb1 ro

If I change it back before I reboot, I don’t have an issue.

What you need:

• iCal client like Sunbird or Lightning from Mozilla
• Apache web server with WebDav installed

How to do it:

1. Install WebDav and password protect a public directory on your web server.
2. Touch a .ics file for your calendar. I called mine matt.ics
3. chmod the directory so the web user can create files and modify the .ics file
4. Install and configure an iCal client that can publish via WebDav. Sunbird is excellent for this.
5. Remove your local calendar from Sunbird
6. Add a calendar to Sunbird using the URL to your empty .ics file
7. Add an event to your calendar. Sunbird should modify the .ics file on your web server. You will probably be prompted for the username and password on the first try.
8. Add that calendar to as many clients as you want. They can all share the calendar. Create more calendars! Party!

apt-get install gcc

And of course you need make

apt-get install make

What you don’t know is that you won’t be able to do anything without your C library and headers. You will get errors that your compiler cannot make executables.

The package you want is libc6-dev

apt-get install libc6-dev

Much better!