Professor Cullen Lecture Notes

COMS148 HOWTOs

Self-Updating Message Console

Precede the TAIL display command with WATCH will allow a rolling console of messages.

        Example:    watch -n1  'tail /var/log/messages'

                      watch -n1 'tail /var/log/secure'

Measure the Elapsed Time of a command

Precede the command with TIME.

        Example:    time rpm -qa | egrep 'office'

Install a USB memory stick

From ROOT or SuperUser
Make a directory under the /mnt directory. I called mine usbdrive. You can use any name that is not already in use.

mkdir /mnt/usbdrive

The USB memory stick is designed to look like a SCSI device to Linux. Optionally, update /etc/fstab to allow accomodation of VFAT (MSDOS) file type for the stick by including the following line:
/dev/sda1 /mnt/usbdrive vfat noauto,user,rw 0 0

make sure that the usb modules are loaded into storage.
modprobe usb-storage

place the usb stick in an available usb port on your machine.
mount the stick
mount -t vfat  /dev/sda1  /mnt/usbdrive

change to the stick's directory.
cd /mnt/usbdrive

list the contents of the stick.
ls -l

write a file to the stick.
echo this is a test > /mnt/usbdrive/testfile
display the new file
cat /mnt/usbdrive/testfile
finish and dismount
umount /mnt/usbdrive

Linux Nucleus System Generation Process (kernel rebuild)

First make backups of your /boot files and /lib modules.
Recommend that you have a spare hard drive that is a duplicate image of your boot drive.
Save the output via redirection of every make step so that you can check for errors.
Change into the kernel source directory.

cd /usr/src/linux.n.n.n

Perform make mrproper to sweep residuals remaining from previous builds clean.
make mrproper

Edit the Makefile and ensure that you select a unique EXTRAVERSION name so as not to overlay your running system components.
vi Makefile

Perform make xconfig or make config and select your options for the nucleus build. You have the option of selecting a previous stored kernel configuration or to config from scratch.
make xconfig

Check and resolve dependencies.
make dep

Clean up garbage and prepare the source tree for the build.
make clean

Perform generation process using completed configuration.
make bzImage

Compile and link any loadable program modules.
make modules

Move all modules into the install area from staging area.
make modules_install

Populate the nucleus, loadable modules and initrd disk and update grub.conf.
make install

Check all logging for any errors.
Check that the "initrd" disk has been built.
Check that the "grub.conf" file has been properly configured.

Reboot and select your new nucleus from GRUB menu.

If there is a problem you can always select your old kernel from the menu.






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