Misc FAQs

Q: What is the most important command in Unix/Linux?
A: 'man man' is the first, 'man less' is the second
Q: What is the first rule in Unix/Linux?
A: Never trust a GUI!
Terminals
System Configuration
CD Burning Configuration
X Windows
DVDs
sound

Terminals

Q: How do I get BitchX to print those fancy ansi characters in an xterm?

A: I'm pretty fuzzy on the details here, but I know you need a font that supports all of those characters. I use sabvga.pcf, you can find it somewhere easily with google. Installing the font is easy, as root, just run these commands:
cp sabvga.pcf /usr/X11R6/lib/X11/fonts/misc cd /usr/X11R6/lib/X11/fonts/misc chmod 644 sabvga.pcf mkfontdir service xfs restart
And then as your normal user, 'xset fp rehash' and open an xterm with the sabvga font, ie: 'Eterm -F sabvga'.
Q: How do I get BitchX to print those fancy ansi characters in the console (not in an X term)?
A: Again, I don't really know the hows and whys, but type this in your console before starting BitchX:
printf "\033[m\033>\033(U"
Q: Why does irssi and BitchX not display correctly when using Eterm?
A: This is because Mandrake's Eterm package uses a default TERM setting of "xterm" instead of "Eterm". While this is technically incorrect for Eterm, it provides for a great deal of compatibility for most other non-free Unixes with outdated terminfo and termcap files. Simply typing "TERM=Eterm" in your shell before running irssi will fix it for that session. To make this change permanent, you can change the default term type in Eterm's theme files:$ mkdir -p ~/.Eterm/themes $ cp -r /usr/share/Eterm/themes/* ~/.Eterm/themes $ perl -pi -e 's/xterm/Eterm/' ~/.Eterm/themes/*/*
Q: How do I easily set my terminal window title?
A: 'echo -ne "\033]0;whatever you want\007"'
Q: That didn't work, it's still set to user@host:cwd
A: 'unset PROMPT_COMMAND' and try it again
Q: My terminal window is printing random binary trash, how do I fix it?
A: The terminal is in graphics mode, just type 'printf "\0217"'
Q: Hey, that was cool... how do I get back into graphics mode?
A: 'printf "\0216"'

System Configuration

A: There's two answers. The 'hostname' command sets the machine's _current_ hostname and won't survive a reboot. But beware that some services, like X, may break if you change the hostname "on the fly". The better way is to edit /etc/sysconfig/network, just change the "HOSTNAME" line and reboot. If dhcp is resetting your hostname to something you don't like, remove the NEEDHOSTNAME line in the appropriate /etc/sysconfig/network-scripts/ifcfg-* file.

Q: How do I add a user? How do I add a shell account?

A: In a root shell, 'useradd username' will create the account, and 'passwd username' will prompt you for the new user's password.

Q: How do I shutdown or reboot linux?

A: There's actually several answers here, I'll stick to one. 'shutdown -hf now' will gracefully shutdown and possibly power off, 'shutdown -rf now' will gracefully shutdown and reset the motherboard.

Q: How do I set the time?

A: 'urpmi rdate; rdate -s clock.sgi.com; hwclock --systohc'

A: You can also install ntp (network time protocol) and add a public time server to /etc/ntp.conf. I'll leave the details up to you.

Q: I hate typing my root password all the time, what do I do?

A: Install and configure sudo, it will let you run processes as root without a password... be careful with this. First install sudo with 'urpmi sudo'. Then run its editor for the configuration file: 'visudo'. Add a line like "garrick ALL=(ALL) NOPASSWD: ALL" replacing garrick with your username. Now anytime you want to run a command as root, just prefix the command with 'sudo', ie: 'sudo rpm -Uvh nifty.rpm'

Q: How do I manage the services configured to start at boot?

First you need to understand that there are two kinds of services: stand-alone and xinetd services. (I just made up "stand-alone" because I don't know what else to call them... they are simply the normal, regular kind) Stand-alone services have init scripts in /etc/init.d/ and are run at boot and shutdown to do various things like start/stop a daemon. Xinetd is a stand-alone service that starts other services on-demand. Thus, xinetd services are never directly started; they are merely enabled.

A: 'chkconfig --list' lists all installed services.

A: 'urpmf /etc/init.d/; urpmf /etc/rc.d/init.d/; urpmf /etc/xinetd.d/' lists all possible services.

A: 'chkconfig servicename on' sets servicename to start at boot-time (xinetd services are enabled).

A: 'chkconfig servicename off' sets servicename to not start at boot-time (xinetd services are disabled).

A: 'service servicename start' starts servicename immediately (not for use with xinetd services)

A: 'service servicename stop' stops servicename immediately (not for use with xinetd services)

A: 'service servicename status' print the current status of servicename (not for use with xinetd services)

A: 'service servicename restart' restart servicename immediately (not for use with xinetd services)

Q: How do I install the ssh daemon?

A: 'urpmi openssh-server; service sshd start'

Q: How do I install the ftp daemon?

A: 'urpmi proftpd; service proftpd start'

Q: My machine does/doesn't boot directly to a X login window, how do I change this to/from the text login console?

A: The "initdefault" line in /etc/inittab controls this behaviour. The number in that line should be 3 or 5. 3 boots to text console, 5 boots to X.

Q: How do I update all of my system software?

A: Add or update your "update source" and use urpmi to select newer packages. See the urpmi page to add your online update source.

  Get your sources updated
# urpmi.update -a

  This command selects updated packages to be installed
# urpmi --auto-select

  Check for kernel updates
# urpmq kernel (compare with 'uname -r')

Q: How do update my ext2 filesystems to ext3?
A: If possible, unmount the filesystem that you want to update. If you can't unmount it, don't worry about it. 'tune2fs -j /dev/whatever' and edit /etc/fstab to change "ext2" to "ext3". If you unmounted the filesystem, mount it now. If you didn't unmount the filesystem, remount with 'mount -o remount /mount/point'. Yes, it's that's easy.
Q: I want to run some command at startup, how do I do this?
A: Put whatever commands you want at the end of /etc/rc.d/rc.local. Be sure that your command exits right away, or put a & after it.
Q: How do I create a printer share in samba using CUPS?
A: Here's a sample "[printers]" section for smb.conf.
Q: checking for GTK - version >= 1.2.0... no *** The gtk-config script installed by GTK could not be found *** If GTK was installed in PREFIX, make sure PREFIX/bin is in *** your path, or set the GTK_CONFIG environment variable to the *** full path to gtk-config.
How do I fix this **** problem?
A: Calm down, take a deep breath, you need to install the package that contains the "gtk-config" program. Two commands: 'urpmf bin/gtk-config' tells you it's in the "libgtk+1.2-devel" package, 'urpmi libgtk+1.2-devel' installs it.

A: This is one small example of a common problem: missing development libraries required to compile some software. Since there are hundreds of various development libraries available in Mandrake, they aren't all installed by default. Simply use 'urpmf lib/libname' to find the package name, then installed the -devel- version of the rpm, 'urpmi package-devel'. An example for the png library:


[garrick@zorak garrick]$ urpmf lib/libpng
libpng3:/usr/lib/libpng.so.3
libpng3:/usr/lib/libpng.so.3.1.2.1
libpng3-devel:/usr/lib/libpng.a
libpng3-devel:/usr/lib/libpng.so
libpng3:/usr/lib/libpng.so.3
libpng3:/usr/lib/libpng.so.3.1.2.4
libpng3:/usr/lib/libpng12.so.0
libpng3:/usr/lib/libpng12.so.0.1.2.4
libpng3-static-devel:/usr/lib/libpng.a
libpng3-static-devel:/usr/lib/libpng12.a
libpng3-devel:/usr/lib/libpng.so
libpng3-devel:/usr/lib/libpng12.so
[garrick@zorak garrick]$ su -c "/usr/sbin/urpmi libpng3-devel"
Password:

CD Burning

Q: How do I burn an .iso file to a CD?
A: With the 'cdrecord' command. First, get your cd burner device address with 'cdrecord -scanbus'. The address is three numbers separated by commas, like 1,3,0. IDE CD burners are usually 0,0,0. Once you have that, here's the command:
```
cdrecord -vv dev=x,x,x speed=x filename.iso
```
The speed is usually 12 or 16, you should know this already.
Q: How do I make the above command even easier?
A: Put the device and speed in /etc/default/cdrecord like this:
```
CDR_DEVICE=0,0,0
CDR_SPEED=16
```
Q: 'cdrecord -scanbus' says it can't find /dev/pg, what can I do?
A: 'modprobe sg' will fix it... to survive a reboot, put "sg" into /etc/modules
Q: I have separate cdrom and cdburner drives, how can I do a direct CD-to-CD copy?
A: cake, 'cdrecord -vv -isosize /dev/cdrom', where /dev/cdrom is replaced with your normal cdrom that has the "source" disc. (personal note, it's the extreme simplicity of commands like this that make Linux beautiful for me)
Q: How do I copy an audio CD?
A: This is basicly directly from the cdrecord manpage: 'cdda2wav -v255 -D0,0,0 -B -Owav; cdrecord -v dev=0,0,0 -dao -useinfo *.wav' (adjust cdrecord's options for dev and speed as required)
Q: How do I burn a directory to a CD?
A: Create an iso file from the directory with mkisofs. It has a dizzying array of options listed in the manpage, but I find this works great: 'mkisofs -J -R -r -o filename.iso /path/to/directory'. Make sure you aren't in the directory at the time, or mkisofs will end up writing an infinitely sized file. The -J option creates Joliet extensions for interoperability with Windows. The -R option creates Rock Ridge extensions for Unix interoperability. The -r changes the owner and permissions within the iso to something sensible for a CD. Now just burn the new .iso as described above.

X Windows

Q: X won't start, how do I repair it?
A: If you aren't using a 3rd party driver (ie: nvidia), then just get to a root shell and run XFdrake. If you are using a 3rd party driver and you really don't know what to do, uninstall it, run XFdrake, get it working with an open source driver (nv for nvidia cards, or perhaps vesa), and then install your 3rd party driver. A good place to look for error messages is in X's log at /var/log/Xorg.0.log (or /var/log/XFree86.0.log for mdk10.0 and earlier).
Q: How do I make an X app from a remote machine display on my local desktop?
A: Before running the X app, type 'export DISPLAY=localIP:0' on the remote machine, and 'xhost +remoteIP' on the local machine.
Q: Can that be done automatically?
A: Use ssh to connect to the remote machine, it will forward the X connection back to your local machine automatically.
Q: How do I start a second X session on my machine?
A: In a terminal window, type 'startx -- :1'. Up to 64 can be started by incrementing the display number.
Q: How do I switch between my consoles and (multiple) X displays?
A: alt and a function key switches virtual terminals, with the addition that you need ctrl to switch out of an X terminal. Right now, you are probably reading this with a web browser in X, hit "ctrl-alt-F1" to switch to your first virtual terminal, hit "alt-F7" to return back to X. The first 6 terminals are text consoles, F7 and up are for X consoles.
Q: How do I take a screenshot in Linux?
A: import -w root filename.png
Q: How do I set my default WM when using 'startx' or using a DM?
A: Set the value of DESKTOP in ~/.desktop or /etc/sysconfig/desktop to one of '/usr/sbin/chksession -l'. (If this file doesn't exist, just make one)
```
$ /usr/sbin/chksession -l
KDE GNOME WindowMaker Enlightenment IceWM Fluxbox Default failsafe
$  cat .desktop
DESKTOP=Fluxbox
```
Q: How do I add a new window manager to the DM's (mdkkdm/kdm/gdm) menu?
A: Add a new entry in /etc/X11/wmsession.d/ (the format should be obvious by looking at the other files in that directory) and run /usr/sbin/fndSession as root.
Q: How do I change my DM?
A: Set the value of DISPLAYMANAGER in /etc/sysconfig/desktop to GDM, KDE, or XDM.

DVDs

Q: What do I do to configure my DVD player in Linux?

A: Probably nothing. Mandrake 8.2 and higher should have recognized your DVD player, associated a raw device to the dvd device, created /dev/dvd which should be a link to the real dvd device, and created /dev/rdvd, which should be a link to the raw dvd device (like /dev/raw/raw1 maybe).
Having the raw device isn't strictly necessary, but it makes a big performance difference on some machines.

Let's verify that this is setup correctly.

Experts, mandrake probably already has this setup, but here's what you do:


raw /dev/raw/raw1 /dev/cdrom
ln -s cdrom /dev/dvd
ln -s raw/raw1 /dev/rdvd

Newbs, this is going to sound a lot more difficult then it really is, but stay with me... Here's the hand holding step-by-step:


[root@zorak root]# raw -qa
/dev/raw/raw1:	bound to major 3, minor 64   <-- note the 3 and 64 (may be
different on your machine)

If 'raw' errors about missing /dev/rawctl, then create a link to /dev/raw/rawctl (ln -s raw/rawctl /dev/rawctl). If 'raw' didn't print anything, then we need to associate a new raw device to the real dvd device. You'll have to find this on your own, it's probably one of /dev/hda, /dev/hdb, hdc, or hdd (or maybe /dev/cdrom, cdrom1, etc) For this example let's say it's /dev/cdrom.


[root@zorak root]# raw /dev/raw/raw1 /dev/cdrom
/dev/raw/raw1:	bound to major 3, minor 64

If 'raw' printed something like "bound to major 3, minor 64", then confirm that your actual dvd device matches that major and minor number.


[root@zorak root]# ls -alL /dev/cdrom
brw-------    1 garrick  cdrom      3,  64 Dec 31  1969 /dev/cdrom  <-- look,
3, 64 matches

Now we have a raw device that is bound to your dvd player. Let's make a few links so that dvd players can find your dvd player easily


[root@zorak root]# ln -s cdrom /dev/dvd
[root@zorak root]# ln -s raw/raw1 /dev/rdvd

Q: What DVD players are available?

A: Several, I'll talk about ogle, xine, and mplayer.
Unfortunately, encrypted DVDs use technology that is illegal to use (Thx MPAA). That means Open Source operating systems like Mandrake can't distribute the software required to read css encypted DVDs.
Fortunately, it isn't hard to install this software on your own. The Penguin Liberation Front has Mandrake RPMs that Mandrake can't otherwise distribute for legal reasons. We can add the PLF as a urpmi source and install our DVD software.
If you've read this site in the past, you know that I complained bitterly about some of the PLF rpms, this was due to compiler versions that they couldn't control . Now that people have updated their software to run correctly with the latest compilers, I can freely recommend all of the PLF rpms.
First, go to http://plf.zarb.org/~nanardon/, and add a PLF urpmi source. Note, PLF updates their packages often, you should run 'urpmi.update plf' regularly. I'll now describe 3 different media players capable of handling DVDs.
Ogle
Ogle is my all around favorite DVD player. It plays well, supports encrypted DVDs, and handles DVD menus really well.
Installing Ogle is cake:
urpmi ogle ogle_gui
Just run 'ogle' and you'll be greeted by a very simple gui. Just go to File->Open Disc to start playing a DVD!
xine
Xine is an all-purpose media player and is already distributed with Mandrake. But we'll need to install the DVD and CSS plugins for xine.
# Install xine urpmi xine-ui xine-xv xine-esd xine-oss xine-plugins xine-arts xine-d5d xine-divx4 xine-dvdnav.
When you run xine, you'll find DVD, d5d, and NAV player options. In order, they are: basic DVD support, encrypted DVD and menu support, dvd menu support. Play with each and decide which works for you. In the past I've not been pleased with xine's playback quality, but it's getting better.
MPlayer
MPlayer is the super player. It can play just about every video file known to man... and play them well! It runs the best, but is the most difficult to setup and doesn't support DVD menus. Building mplayer can be an involved operation.

urpmi mplayer
And have fun!

Sound

Q: In front of various commands, what's "soundwrapper" for?
A: cannonball tells us, some things don't have the concept of "sharing" /dev/dsp. They try to open it exclusively. soundwrapper gives them a fake device that they can latch on to but in the background is really sharing it.

Send me more tips and tricks for Mandrake users and I'll include them here garrick@speculation.org