[RHCE] Notes from Prerequisites Session 1
Frye, Matthew
Matthew.Frye at rexhealth.com
Wed Sep 17 09:59:34 EDT 2003
Max and RHCE Gang,
It's probably going to be more useful than not for at least one
person to go into lecture mode at each session. This will keep us on track
and keep the splintering into side discussions to a minimum. I volunteer to
guide this evening's discussion of the second half of the prerequisites.
Assuming we all now (or very soon will) have the book, you can go through
the contents and volunteer for future sessions. Currently, I have the
following session volunteer list:
Gregory - Boot process (Chap 2, Chap 4), Squid (Chap 9), Apache (Chap 8)
Chris - NTP (Chap 9), DNS (Chap 9), DHCP (Chap 9)
Matt - Samba (Chap 8), Sendmail/Mail Services (Chap 8), NIS (Chap 10), NFS
(Chap 9)
Obviously, those who volunteer, however familiar they are with the
topic, will need to read ahead and become familiar with how well or poorly
Michael Jang addresses these topics. That will keep the discovery to a
minimum during study group. Let me know if you want to volunteer for a
particular session. Some topics for which we could use volunteers (or
extra-group speakers) are:
Kernel (Chap 6)
X/Gnome/KDE (Chap 7)
Security & Pam (Chap 10)
Linux Rescue & Recovery (Chap 11)
Chapters 2, 3, and 4 appear to be more general in nature, so unless
someone else is interested in leading these sessions, I volunteer to lead
them also. We can take a few minutes for "Group Business" this evening to
discuss and iron things out in case anyone has any concerns.
Matt
> ----------
> From: Max T. Woodbury[SMTP:Max.TenEyck.Woodbury at verizon.net]
> Reply To: Red Hat Certified Engineer exam study group
> Sent: Tuesday, September 16, 2003 6:07 PM
> To: Red Hat Certified Engineer exam study group
> Subject: [RHCE] Notes from Prerequisites Session 1
>
> First, I'm sorry for going into 'lecture mode'. I understand that it
> can be annoying but we were drifting and there is a lot of material to
> cover.
>
> The topic was basic operations that are needed to use Linux. This
> material is covered in first section of the Osborn RHCE 3rd Ed. Since
> the purpose of our gathering is to get an RHCE, I'm going to skip a
> lot of 'other *NIX does it this way' stuff that was discussed and
> focus on what Red Hat Linux provides.
>
> NOTE: I've added a little that got skipped. Marked with (+).
>
> The 'vi' editor is small enough that it can fit on the 'rescue disk'
> and functional enough to be useful. 'emacs' is too big and 'sed' is not
> as functional.
>
> vi - roughly equivalent to MSDOS 'edit'
> This is a 'modal' editor. There are three basic modes. You start in
> 'navigation' mode. You have to go to 'edit' mode to insert text.
> There is also a 'command' mode.
> In both navigation and edit mode, the arrow keys move you around.
> There are several ways to go from navigation to edit modes. The
> simplest is 'i'. To go from edit back to navigation use the 'esc'
> key. Command mode is entered with the ':' key. Exit vi
> with the :wq command to save what you've done or :q! do discard what
> you've done.
>
> Cut, Copy and Paste from navigation mode: Cut - <n>dd where <n> is a
> decimal number deletes <n> lines and saves the last one in a buffer.
> d<n>d deletes <n> lines and saves all <n> in the buffer. Copy -
> y<n>y copies <n> lines into the buffer without deleting starting
> with the current line. Other commands also save stuff into the
> buffer. When something is put in the buffer, the previous contents
> are lost. Paste - p inserts the contents of the buffer after the
> cursor - into the next line if the buffer contains lines. P inserts
> before the cursor. (No, I'm not absolutely sure that <n>dd and d<n>d
> do different things. I suggest everybody try it and see.)
>
> Directory structure - RH's directory structure is not entirely
> 'standard', but its what is needed for the RHCE. Mount points are
> places other file systems can be inserted into the basic directory
> tree. (+) Linux and *NIX in general do not use 'drive letters' to
> designate which file system is being used. It's all one huge tree.
>
> / The 'root' of the file system 'tree'.
> /bin For user command stuff needed at boot time. NOT a mount
> point.
> /boot Basic boot time stuff. Often a mount point.
> /dev 10,000 device names and more. NOT a mount point.
> cdrom The CD-ROM drive (+)
> fd<0,1> Floppy drives (A: and B:)
> hd<a-t>[n] IDE drives (up to 16) with partitions. 0 is the whole
> disk.
> mouse The mouse (+)
> sd<a...>[n] SCSI drives and partitions. aa, ab... if there are
> more than 26.
> tt... 'terminals' (+)
> /etc System configuration files - lots of em. NOT a mount point.
> /home Where the user's stuff is. A mount point on all but the
> smallest systems.
> /initrd A 'RAM' disk used during boot. Dismounted after the initial
> phases of the boot process to keep its contents safe from
> glitches.(+)
> /lib Libraries needed at boot time. NOT a mount point.
> /lost+found Stuff that 'fsck' has recovered. There's one for each real
> file system.
> /misc Optional mount points for the 'automount'er.
> /mnt Contains a bunch of mount points. NOT a mount point under
> RH.
> /opt 3rd party stuff.
> /proc Always a mount point - connects to a 'pseudo' file system
> that lets you see inside the kernel.
> /root 'root's home directory. NOT a mount point.
> /sbin For admin command stuff needed at boot time. NOT a mount
> point.
> /tmp Temporary stuff. Gets pruned from time to time. NOT a mount
> point.
> /usr Catchall directory. Can be a mount point.
> bin The rest of the user command stuff.
> lib The rest of the libraries
> sbin The rest of the admin command stuff.
> tmp More temporary files. (+)
> ... Lots of other stuff.
> /var System state stuff and other information. Can be a mount
> point.
> log Log files. See /var/log/rpmpkg for a list of RPMs installed.
> tmp Temporary files that are pruned on each boot. (+)
> ~ Your home directory. Specified in /etc/passwd.
> ~<name> 'name's home directory.
>
> You can add other directories at the bottom level as you see fit.
>
> fdisk Similar to its MS-DOS equivalent but does a lot more. 'm'
> displays help.
> mkfs Makes a file system. I haven't played with this. Dangerous.
> fsck Check a file system. The file system must NOT be changeable
> unlike the MS-DOS chkdsk or scandisk equivalents.
> mount Connect a device to a mount point using a file system. Uses
> /etc/fstab to 'fill in the blanks'.
> umount Reverses the effect of 'mount'
>
> pwd Displays your 'working directory'. PWD is a shell symbol
> with the same information. $PWD can be used to substitute
> that value into a command.
> cd Change directory - like the MS-DOS command. Without an
> argument it send you to '~'.
> ls Like MS-DOS 'dir', but a huge number of options are
> available. Note the effect of the 'language' definition on
> the order of list. (+) The -d option displays directory
> attributes rather than contents when using wild cards.
> find <start> <actions> Does <actions> for everything in the <start>
> tree. The default <action> is to print the name
> of whatever. A useful <action> is -name which
> does name matching. Take care to 'escape' any
> leading wild card characters with '\'. (+)
> locate Searches a database for file names. The database is normally
> rebuilt every night. This can eat a lot of computer time at
> 4 AM and will often trigger faults on marginal hardware.
> cat Equivalent to MS-DOS 'type'. Note that Linux 'type' does
> something else.
> less, more Similar to MS-DOS 'more'. 'less' is more useful and can
> shift you into 'vi' under some circumstances.
> head, tail Displays the first or last part of a file. 'tail -f' lets
> you 'follow' a file as it is being written.'
> cp Equivalent to MS-DOS 'copy'. Check out the '-a' switch.
> mv Equivalent to MS-DOS 'move'.
> ln Like 'cp' but creates a 'link' rather than actually making a
> copy of the file. It provides an 'alias' for the file.
> rm Equivalent to MS-DOS 'del'. (+)
> grep, egrep Look for something inside a file. Note that there is a
> 'fgrep' for 'fast grep' but 'egrep' is usually faster than
> 'fgrep'...
> sort You guessed it... It uses the local 'language' definition to
> determine the order, so it puts things in the order 'A',
> 'a', 'B', 'b'... (+)
> wc Counts things, lines, words, characters.
> ps Displays 'processes'. Lots of options.
> who, w Displays 'users'.
> lpr, lp Send a file to the printer. Spooled. Defaults can be set for
> each user and globally. There are filters that try to do
> the 'right thing' with 'binary' files.
> file Examines a file to determine what kind of file it is. This
> is used by lpr to figure out what the 'right thing' to do
> to a file is.
> lpq Displays the spool queue.
> lprm Removes a 'job' from the spool queue.
> pr -f Adds headers, page numbers, ... to simple text files.
> man Displays help on a topic, particularly commands. It helps a
> lot to include the 'man pages' in any installation.
> info, pinfo Another help system.
>
> su - Become the 'super user'. The '-' is short for '-l'. It means
> 'do a login' to establish a complete environment. This adds
> the 'admin' commands to the normal user repitoir.
>
> Wild cards - '*' matches any number of characters, including none. If
> used alone, it becomes a list of files in the current working
> directory. '?' matches any one character. [...] matches any character
> in the list '...'. Ranges can be abbreviated. For example [A-Z] matches
> any upper case letter. (+).
>
> We stopped on page 21.
>
> Things in the book that have been skipped:
>
> Configuring printers. I expect that this will be covered under 'cups'
>
> Tarballs. It says that a lot of packages are distributed as 'tarballs'.
> While true, the exam is almost certainly only going to cover
> installation using RPMs. (Tarballs are needed to build RPMS. Is
> building RPMs covered by the exam?)
>
> fdisk details.
>
> Things that the book suggests that may be poor practice:
>
> Editing the /etc/passwd file with vi. Use 'vipw' to create a lock file
> that keeps other tools out of that file while you're fiddling. Better,
> use the admin tools like 'add_user'.
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