Today, continue on your path to RHCE certification. Learn about creating a new kernel the easy way, kernel sources, recompiling a kernel, and the cron and at systems. Take notes, because there's a test at the end. This comes from chapter five of Red Hat Certified Engineer Linux Study Guide (Exam RH302), fourth edition, by Michael Jang. (McGraw-Hill/Osborne, 2004, ISBN: 0-07-225365-7).
1. C. This is the system-wide shell script executed for all users; A and B are incorrect because there are no such files. While each user does get their own hidden configuration files in their home directories, they apply only to that user. D is incorrect
Setting Up and Managing Disk Quotas
2. C. Enable grace periods; set the soft limit to 40MB, and the hard limit to 50MB. This will warn users they are over their limit after the grace period, but will make sure they do not exceed the 50MB true maximum barrier; A is incorrect because the soft limit must be less than the hard limit. B is incorrect because it is actually the same as A. D is incorrect because C does the job.
3. B and C. The usrquota and grpquota options allow the configuration of quotas on the given filesystem on user and group bases; A and D are not valid options for /etc/fstab.
The Basics of the Kernel
4. D. The modprobe -t net command tries each module from the /lib/modules/kernel_version/kernel/drivers/net directory, until it reaches the end of the list or finds a module that works for a network interface; A, B, and C are incorrect. Linux needs to load the card module before you can connect to the network, so C is incorrect. You might try loading all modules manually, but that is not efficient, so A is incorrect. While the modprobe \* would test all options, it is also not efficient, so B is also incorrect.
5. D. These commands together compile your modules and then place them in the appropriate directory trees. Because these are kernel-related commands, they have to be run from the /usr /src/linux-2.4 directory; A, B, and C are incorrect. The make modules command just compiles the modules, so A and C are not correct. The /lib/modules/kernel_versiondirectory is the wrong place to apply these commands, so B is incorrect.
New Kernels, the Easy Way
6. D, None of the above. GRUB is automatically updated when you install a new Red Hat kernel from a Red Hat RPM; however, you may want to change the value of defaultin /etc/ grub.conf. A new Initial RAM disk file, initrd-versionnumber,is also added to the /boot directory. You donít need to change /usr/src/linux-2.4/.config file unless you want to recompile this new kernel; A, B, and C are all not required and are therefore incorrect.
7. B. The /usr/src/linux-2.4 directory is normally soft-linked to the actual directory with the active kernel source files; A, C, and D all specify directories that arenít linked to the Linux kernel source tree. (However, the situation was different before Linux kernel version 2.4; answer A was correct for older Linux distributions, such as Red Hat Linux 7.0.)
Recompiling a Kernel
8. C is correct because there is no kernel configuration utility based on the make windowconfig command; A, B, and D are all incorrect. In the /usr/src/linux-2.4 directory, the make config, make menuconfig, and make xconfig commands all call kernel configuration utilities.
9. D. The make install command in RHEL 3 automatically loads the files and data related to your recompiled kernel in the /boot directory. It also installs a new Initial RAM disk and revises the GRUB boot loader; A, B, and C are all incorrect. While the recompiled kernel is stored in the directory noted in answer A, this action does not create an Initial RAM disk. B is incorrect as more action is required. C is incorrect as the revised Red Hat kernel RPM probably does not reflect your custom kernel configuration.
The cron and at Systems
10. A. The syntax for cron is minute, hour, day of month, month of year, weekday, and then the command. This answer corresponds to 4:00 A.M. on the first of every month; B executes at 4 minutes after 1 in the morning for every day. However, there are only four time fields, not five, so the entire line would be considered invalid. C is incorrect because it runs the job at 4:00 A.M. on the 31st of the month, and then only if the month has 31 days. D is incorrect because it executes the program at one minute after 4:00 A.M. And there are only four time values in this line, which makes it invalid.
This is part one from the fifth chapter of Red Hat Certified Engineer Linux Study Guide (Exam RH302), fourth edition, by Michael Jang. (McGraw-Hill/Osborne, 2004, ISBN: 0-07-225365-7). Check it out at your favorite bookstore today. Buy this book now.