Software FAQ

Q: Why is Application XY not starting up? Why can't I open certain files?

A: The configuration of the application may be broken. Try moving the hidden folder which contains the configuration to another one by typing mv ~/.XYconfig ~/.XYoldconfig and then start the application again. If you see no changes or want your configuration back, just move the folder back to its original name.

Q: How can I reboot my Tardis Workstation?

A: NEVER reboot your Workstation. Maybe there are other students logged in and working on it or any important jobs running. Probably it is only your crashed browser that blocks the keyboard or mouse. Login from an other machine and find out which process is locking the machine up. Try top to figure this out.

On a Linux Workstation you can use the key-combination Ctrl+Alt+Backspace to restart your Xserver.

A very effective and simple way to 'unblock' a machine is to walk to one which is working and then type:

ssh username@blocked_machine kill -TERM -1

If you still have problems, mail to support@ee.ethz.ch

Q: I cannot log in anymore into the X environment on a Linux Tardis Workstation. What can I do?

A: 1. Change to a Console (CTRL-ALT-F1) and log in with your username.

2. Run the tool xauth-fix

3. Exit from console and change back to the GUI (CTRL+ALT+F7).

4. Try to log in again.

If this still not work and you get an error message about lock-files then:

5. Go back to a Console again and log in.

6. With

lsof | grep /home/<username>/.qt

check which processes still have an open "file" in /home/username/.qt and kill the processes (with kill -9 <pid>)

7. Remove the lock-files under ~/.qt and logout from console.

8. Change to the GUI (CTRL+ALT+F7) and try to log in again.

Note: If you are working on a Solaris Tardis Workstation you cannot switch to a console as explained above. Then log in via a failsafe session (choosable via the loginmanager under "Session") and perform there the above operations.

Q: Why is Firefox/ Thunderbird telling me "already running", "profile in use" or "No running window found"?

A:

UNIX:

First, check if you have firefox/thunderbird instances running

ps -ef | grep <username>

kill these with kill <pid>

Then delete the following files:

~/.mozilla/firefox/<profile-name>/lock

~/.mozilla/firefox/<profile-name>/.parentlock

Windows: Check with the task manager if firefox/thunderbird is running, if yes, kill it.

Delete the following file:

• W:\Application Data\Mozilla\Firefox\Profiles\<profile-name>\parent.lock

Q: Why can't I update my Netscape Bookmarks anymore?

A: Most likely you have a ~/netscape/lock file hanging round. This file gets created when you start netscape. When you exit netscape, the lock file gets removed. There may be situations when Netscape cannot remove the lock file before it dies. For example after a crash. When you restart netscape it will see the lock file and conclude that there is another copy of netscape still running. If you are sure that this is not the case, type: rm ~/.netscape/lock to remove the lock file.

Q: How can I have zsh as my default shell?

A: Everybody on the system has to use tcsh as login shell, because this allows us to put a standard configuration into each account. But don't worry, it's no problem to change the shell for all further operations after the login. Just put setenv SHELL /usr/sepp/bin/zsh into your ~/.login  file. Each terminal you start will then invoke zsh.

Q: Why does putting setenv PATH in my .login not work?

A: What ever you put in your .login file gets overridden by the contents of the .cshrc file.

Some background: When you log in, the following files are read by your tcsh in this particular order:

/etc/.cshrc
~/.cshrc (The .cshrc file in your home)
/etc/.login
~/.login (The .login in your home)

The files in etc contain our system-wide defaults. What ever is in there, it will always get processed. When ever you start up a new xterm the tcsh which runs inside the xterm reads the files /etc/.cshrc and ~/.cshrc.

The solution to your problem is therefore to put your path settings into your ~/.cshrc file. But be careful, try not to replace the system defaults, rather add to them: set path=( ~/bin $path ).

If you add this fragment to your ~/.cshrc file, the tcsh will look in your ~/bin directory for an executable before using the one installed on the system.

Some people might get annoyed by the Message of the day, which is dumped on their screen whenever they log on. If you create a ~/.hushlogin file nothing will be printed out when you log-in.

Q: How can I synchronize my computer's time with the ETH time server?

A: You can use our time server swisstime.ethz.ch with any Network Time Protocol client.

Q: How do i know what kind of processor I am working with?

A: Just run psrinfo -v

If you want to know that platform and kernel you're on, run uname -a

Q: How do I use VNC?

A: Start a vnc-server on the machine you want to control, with vncserver :1 (:1 means display 1). You will be asked to define a password for accessing your server and another one for just observing without interacting. After that, your server is up and running and you can connect to it with any available VNC-clients (e.g. TightVNC) by entering the hostname you want to connect to, like hostname:1.

Q: Why does XForwarding not work anymore?

A: If you're getting messages like these while trying to forward an X-session:

user@laptop:~/bin$ ssh -X user@login.ee.ethz.ch
user@login.ee.ethz.ch's password:
Last login: Mon Apr  2 13:39:11 2007 from vpn-global-083-SunOS 5.8 Generic_117350-44 UNW,Sun-Blade-1500
user@tardis-a05:~>matlab
X11 connection rejected because of wrong authentication.
X connection to localhost:11.0 broken (explicit kill or server shutdown).

or like these:

Xlib: connection to "localhost:10.0" refused by server
Xlib: PuTTY X11 proxy: MIT-MAGIC-COOKIE-1 data did not match
Warning: Unable to open display localhost:10.0
(mit-magic-cookie)

Log in first via ssh and try the command xauth-fix. If this doesn't help, let us know at support@ee.ethz.ch

Q: How can I find storage-hungry files in my home?

A: Using the following commands, you can get a list of items in your home, sorted by size in MB:

gdu -sm ~/.??* ~/* | sort -n | less

If you replace -sm with -sk, the size will be shown in KB.

If you prefer a graphical approach, try: gdu -k ~| xdu. This will take some time to complete, but should result in a graphical window showing what is using up your precious quota space.

If this doesn't convince you, you can try a tool like treesize.

Q: How can I give several users write access to a directory of mine?

A: This trick can be performed with the commands setfacl and getfacl (ACL means Access Control List). They both have a manpage. Since the concepts of using them is not that simple, you might want to look at the following example.

User tanja wants to setup a directory ~/community which she and her friend andrea can access but which is closed to all other users.

She creates a file myaclswith the content:

# basic permissions for ~/community
user::rwx               # the owner of the directory has read write execute access
group::---              # group has no access
other:---               # neither has all the rest of the world
# acl for ~/community
user:tanja:rwx          # the same for tanja
user:andrea:rwx         # and andrea
mask:rwx                # the highest access privilidge one can get is read write execute
# when new files are created within ~/community, they get the following acl
DEFAULT:user::rwx       # the owner of the new file has read/write/execute access
default:user:tanja:rwx  # tanja will have read/write/execute access to all the new files
default:user:andrea:rwx # and so does andrea
default:group::---      # the group has no access
default:mask:rwx        # the highest access will be read/write/execute
default:other:---        # others have no access

Now she executes setfacl -r -f myacls ~/community to apply the new permissions to ~/community. With getfacl ~/community she can check that everything worked fine.

Please note that the quota rules still do apply here. If andrea has no quota on the disk where tanjas home is, she will still not be able to write to this directory.

In addition, the default entries only apply on directories, for files there are no default ACLs.

Q: How can I connect to X-servers via Putty SSH or SSH Client?

A:

PuTTY SSH:

1. Open the PuTTY configuration window in Start->Programs->Internet->PuTTY

2. Choose SSH->Tunnels in the left part of the window

3. Check 'Enable X11 forwarding' and enter 'localhost:0' in the X display location-window underneath

SSH client:

1. Open SSH client in Start->Programs->Internet->SSH client

2. Open 'Settings..' in the Edit Menu
3. Choose 'Tunneling' in the left part of the window

4. Check TunnelX11 connections

Alternaltively, you can install X-Win32 from Add/Remove Programs, the newest version has integrated ssh support, and allows you to setup a 'rlogin'-style directly.

How can I mount CDROMs, DVDs or FLOPPIES on ISG.EE Linux?

A:

cd /media/cdrom/

# or for other devices

# cd /media/cdrw, /media/cdrw2,

# cd /media/dvd, /media/floppy

# read your files

cd / 

# after a short while the directory is automagically unmounted

How can I access USB or Firewire devices (memorystick, digital camera, external disks) on Linux?

A:

Before reading any further: If Your Device(e.g. Memorystick) has been initialized by a Macintosh machine, your system might hang. Take precautions.

Mounting USB Devices under Linux

You only need to plug in Your USB Device on Your Linux machine. If the device is suitable, it is automatically mounted.

Mount points are the numbered directories /usbstorage/usbstorage*/ (* is the number).

The directory used for the currently mounted USB-Sticks can be determined by running a

ls -ld /usbstorage/*

The listing will show one or more directories owned by audio group. This group is used to make the computer's hardware accessible to the user sitting at the machine.

Remarks

Each individual memorystick will receive its own mount point, even if unplugged in between.

This means that if Your memorystick has been mounted under /usbstorage/usbstorage0/, its content will be accessible on this path, even if some other memorystick is plugged in.

When the machine is rebooted, this assignment is restarted and probably receive another mount point. Basically every USB device that exports a Storage Class interface should work. USB Memorysticks and Digital Cameras were tested and worked.

Only partitions formated with FAT are recognized.

Using the internal Cardreader (USB)

The devices inserted in the internal card reader (where present) can be accessed under /usbstorage/CardReader_*.

Sharing a Memorystick between Macintosh and Linux machines

Unfortunately, Linux is confused by the Macintosh partition table and might even crash. To solve this problem, the partition table needs to be cleaned. As this action is dangerous and needs additional priviliges. Contact ISG support for assistance.

Mounting Firewire Devices under Linux

The method is the same:

Plug the device in and search for the correct subdirectory in /ieee1394/*

How can I map the META key to the left "windows" key (Emacs)

Per default the left "alt" key will be the META key in Emacs. When you like to change the META key to the left "windows" key add the following lines to your startup script (.login)

xmodmap -e 'remove mod4 = Super_L'
xmodmap -e 'remove mod4 = Hyper_L'
xmodmap -e 'add mod4 = Meta_L'

Q: What is that `Recycle_Bin` directory in my home folder?

A: This folder only appears if you work with Windows as well. Our Samba servers are configured, that they move deleted files into this directory. Every night a script on our servers deletes then the files which were longer than 24 hours in that directory. You can suppress the usage of that folder if you place a file called AAA_DONT_SCAVENGE_ME in it.

Q: Where should I save my data?

A: If you're using your data exclusively on Windows, you can easily use the "My Documents" Folder. If you work regularly under Unix as well, then it's probably better to put your data in your H: drive, since it is also your /home/ directory on tardis.

Q: How can I use a Mic on Linux based Tardis Workstations?

A: Connect your Microphone and Headphone to the front panel of your Tardis Workstation. (the default settings are for the front panel, but you can make your own settings supporting the rear panel) and load the mixer state file.

alsactl -f mixerfile restore 0`

Or you could use alsamixer or kmixer to configure the sound mixer manually

For recording use rec, a simple command line recording tool or audacity a gui recording tool.

Config Files

tardis-b* mixerconf-tardis-b

Q: How can I compile/install additional software on a tardis machine?

A: Regular (non-root) users cannot use the commands apt-get or aptitude in order to install precompiled .deb-packages on a tardis machine. However, you may download the source code, compile it and install the desired software in your home-directory. The Following description may vary as the case arises (the README and INSTALL files in the source code directory usually give detailed information).

1. Download source code

2. Enter source code directory and execute ./configure. Make sure you set the necessary path variables.

./configure --help

shows you which variables can be set. Most libraries are contained in /usr/lib/ and don't need to be specified. If a desired library is not found, you may check /usr/pack/ or www.sepp.ee.ethz.ch/sepp-debian/ for the path. Also set the installation path using the option --prefix=<path>, here is an example:

./configure --prefix=/home/<home-directory>/<folder>

3. Once the configure script terminated successfully, execute make in order to compile source code

4. Execute make install in order to install software