100 Linux Tips and Tricks

Tip 16: Annoying boot messages

When recompiling your kernel, you might end up seeing strange messages on bootup like:

modprobe: cannot find net-pf-5 modprobe: cannot find char-major-14

These are messages from the modules loader telling you that he can't find specific modules. This usualy happens when you compile modules, but modprobe tries to load modules that were not compiled and it can't find them. The way to remove those messages is to set the modules to off. In the file /etc/conf.modules you may want to add:

alias net-pf-5 off alias char-major-14 off

This will stop modprobe from trying to load them. Of course you could also try to resove the problem by compiling the modules and make sure modprobe knows where they are.

20

100 Linux Tips and Tricks

Tip 17: Programs on CD-ROM

http://metalab.unc.edu, ftp://ftp.cdrom.com and more are sites with a lot of programs available freely for Linux. But you may not want to download gigabytes of data over a slow Internet link.

Several places offer a bunch of free programs on CD-ROM. http://www.cheapbytes.com and http://www.linuxmall.com are 2 places that can sell multiple CD-ROMs with all those programs for a very low price:

21

100 Linux Tips and Tricks

Tip 18: International console

Most Linux distributions are configured to use a US english keyboard. If you need to write on a french or any other kind of keyboard, you will want to change the locale so special keys like accents appear in the console.

The way to do this is to change the system locale with a program called loadkeys. For example, to enable a canadian-french locale, you need to add this line in your startup files:

loadkeys cf

Here cf means the canadian-french keyboard. Other locales are us, fr and more.

22

100 Linux Tips and Tricks

Tip 19: Multiple kernels choices

When you compile a new kernel, you will often change your configuration. This means you may forget to include an important driver, like the IDE driver, or otherwise make your system unbootable. The solution is to always keep your old kernel.

When you compile your kernel, the compilation procedure will often copy your old kernel into vmlinuz.old. If it does not, you can do it manually. What you should do is add an entry to /etc/lilo.conf allowing you to boot your old kernel. You should view the lilo man page for the complete syntax. You could also add entries for different kernels, for example if you want to have an older stable version of the kernel and the newest development version on your system.

Note that some distributions name their kernel with the version they represent. For example, your current kernel may be /boot/vmlinuz-2.0.36-0.7

23