Tips and Tricks

Windows

Greek Spell Checking for the Mozilla and Mozilla Thunderbird email clients

In order to have Greek spell checking for the previously mentioned clients ( Mozzila mail, and Mozzila Thunderbird Mail) go to ftp://ftp.cs.ucy.ac.cy/pub/Windows/Thunderbird/Greek_Dictionary/ and download the el.aff and el.dic

Save the downloaded files in the following locations:

• For Mozilla mail in C:\Program Files\mozilla.org\Mozilla\components\myspell
• For Thunderbird in C:\Program Files\Mozilla Thunderbird\components\myspell

--- nsc

Start/stop Windows services remotely

Use the command sc to enable and start the service: --- Tmaria

sc \\hostname config <servicename> start= auto

sc \\hostname start <servicename>

Use the command sc to disable and stop the service:

sc \\hostname config <servicename> start= disabled

sc \\hostname stop <servicename>

To initiate immediate contact between a client computer and WSUS server

On the client computer, at the command prompt, type

wuauclt.exe /detectnow This will force the client computer to initiate contact to WSUS, and appear in WSUS console

To remove Software Restriction Group policies settings on windows XP pcs

When users can not logon when wrong Software Restriction group policies have been set-up on DC you can follow the next steps to solve the problem: Reboot the pc in safe mode Run regedit and delete the subkeys of HKLM\Software\Policies\Microsoft\Windows\Safer

How to move folders and files on WindowsXP/2000/2003 and retain security permissions (useful when moving profiles dirs)

Use robocopy command from windows 2003 Resource Kit Tools. The syntax is : robocopy <source> <destination> /e /move /copyall Check [1] for all command options

How to install network printer for all users on windows machines

Execute the command from a windows server. Using the above command, will also install the network printer for all users. Use the tool \\kalliopi\sys-data\Windows\Tools\addglobalprinterremotely.cmd. The syntax of the command is: addglobalprinterremotely.cmd <remotemachinename> <printservername>\<printersharename>

How to reset owners on folders and subfolders on Windows XP

Execute the command
subinacl.exe /subdirectories <directoryname>/* /setowner=<username>

Trying to delete computer object from AD your prompted that the object is a container

Most objects in AD can be containers for other objects. They don't have to be an OU to be a container. It could possibly be a container for other objects such as printers. To check this, in ADUC turn on View->Users,Groups, and Computers as Containers. Now click on the computer, and in the right plane you'll see what objects it contains. If it printers, you can most likely move it or delete it.

Windows Messenger won't start

While trying to start up Windows Messenger, the mouse cursor shows an hour glass for a few seconds and then nothing. Windows Messenger doesn't come up and no error message is shown.
Uninstall, Re-install.... makes no difference.
And the Windows XP event viewer displays the following error:
The description for Event ID ( 4 ) in Source ( (MSN/Windows) Messenger Service ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event.
Solution:
Using the registry editor, follow this path:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Messenger\Client
There you should see a key called PreventRun with a value set to 1. Change the value to 0.
Try Windows Messenger again. Should work fine now.

AIX

How to start the Xserver

startsrc -s dtsrc

How to solve 0516-787 extendlv: Maximum allocation for logical volume Name is Value Possible Causes

Using the System Management Interface Tool (SMIT), you specified a value in the Number of ADDITIONAL logical partitions field to try to increase the logical volume size beyond the maximum number of logical partitions.
Procedures for Recovery
Use SMIT to change the logical volume.
Use the SMIT Physical and Logical Storage--> Logical Volume Manager--> Logical Volumes--> Set Characteristic of a Logical Volume--> Change a Logical Volume menu option to specify a new number of logical partitions in the MAXIMUM NUMBER of LOGICAL PARTITIONS field.

Linux

Mounting a windows shared folder from linux

mount -t smbfs -o username=<YOUR_USERNAME>,workgroup=CS-UCY-AC-CY //<WINDOWS_MACHINE_NAME>/SHARED_FOLDER /PATH/TO/YOUR/MOUNTPOINT

Reclaiming free space after deleting log files

If a filesystem is full (for example /var) and you delete some log files in order to make some room on the filesystem, you observe that the space does not appear to be there when running the df command. The solution to this is to restart the application which is using the log files deleted. e.g: if you delete an apache log file then you should restart the httpd service.
% service httpd restart will do the trick nsc

Typing Greek in Linux Fedora Core 4 (changing the keyboard maping to greek 319)

Note that for FC6 this is no longer necessary. The language and keyboard setup can be changed from the System/Preferences/Keybord tool.

First of all download this file from the UCY CS Dept. ftp server [2] ... This file contains some files...We are interested on the two of them: el319 and en319! You have to put them in the following folder(be sure you are logged in as a superuser). So lets start : Extract the contents of the package in a folder

    tar -xvf gr319kb.tar.bz2 

and copy those two files in the /etc/X11/xkb/symbols/pc/ folder... you can run the following commands from that folder:

    cp el319 /etc/X11/xkb/symbols/pc/el319

    cp en319 /etc/X11/xkb/symbols/pc/en319

(After that if you want to load those key-maps you can type :setkeymap el319 (or en 319) in order to have the mapping you need...(NOT RECOMENDED))

If you want to have the mapping loaded in the system by default and switch between mappings with alt-shift you have to make some changes to the file /etc/X11/xorg.conf . So , open that file with an editor and find the line that describes the keyboard mapping configuration...That should be under the Section "InputDevice". After all those comments we have to change(or/and add) some lines and make them look like this:

...

Section "InputDevice"

...

Identifier "Keyboard0"

Driver "kbd"

Option "XkbModel" "pc104"

Option "XkbLayout" "en319,el319"

Option "XkbOptions" "grp:alt_shift_toggle,grp_led:scroll"

EndSection

...

change everything that needs to be changed in those lines and save the file... Restart the X server(or the computer) and the new configuration will be loaded. From that time you can change the keyboard layout by pressing alt-shift(just like windows!).

NOTE:After the restart you will be asked to use: gnome or X configuration...Be sure you choose the X configuration!

--Asterios Katsifodimos

Variable Indirection in csh scripting

Although the csh (and therefore? tcsh) are considered not to support variable indirection as bash does with the use of the (!) exclamation mark, the following command does the trick nsc set temp=`eval echo \$${x}`

 bash example
$a=x
$x="Hello There"
$echo $a
x
$echo $!x
Hello There
$

 tcsh example
%set a=x
%set x="Hello There"
%echo $a
x
%eval echo \$$x
Hello There
%set tmp=`eval echo \$$x`
%echo $tmp
Hello There

Seting extented permissions for OPNET directories

The following commands must be used in order to give rwx permissions to Mylonas for the opnet directories

  /usr/bin/setfacl -d --set u:<USERNAME>:rwx,m:rwx /path/to/<USERNAME>
  /usr/bin/setfacl -m u:mylonasy:rwx /path/to/<USERNAME>
  /usr/bin/setfacl -d -m u:mylonasy:rwx,m:rwx /path/to/<USERNAME>

How to allow XDMCP run on linux server

In order to allow other clients to connect to a linux machine, by X-win, the following steps should be followed:

• 1. /etc/X11/xdm/Xaccess file: uncomment the line that allows all host to get a login window.
• 2. /etc/X11/xdm/xdm-config file: comment out (with !) the last line which contains DisplayManager.RequestPort:0
• 3. Enable [XDMCP] service from /etc/X11/gdm/gdm.conf (/etc/gdm/custom.conf for FC5 kekkos) and /etc/kde/kdm/kdmrc files. The required changes in the custom.conf file are:

 [daemon]
 RemoteGreeter=/usr/libexec/gdmgreeter
 
 [xdmcp]
 Enable=true

If you are too lazy to edit the file then go to System->Administration->Login Screen->Remote-> and set Style to "Same as local"

• 5. Reboot the machine

How to rip (create) an ISO image from a normal CD

In order to create an ISO image from a any normal CD go to any Linux machine and do:

dd if=/dev/cdrom of=<my_cd_image.iso>
where <my_cd_image.iso> is the ISO file name you are creating.

This assumes that your cd drive is called /dev/cdrom

To test that you have actually created an ISO image do:

mount -t iso9660 -o ro,loop <my_cd_image.iso> /mnt/cdrom
cd /mnt/cdrom

List the files in the ISO image. You should get a listing of the CD files in the ISO image.

Starting Condor on the linux rack servers

For the condor to run correctly one must start it first on cs919

to start condor type: /usr/local/condor/sbin/condor_master
on some machines the executable is under /usr/local/condor/
Check that condor is running on cs919 condor_status and then start it on the rest of the machines using the same command The list of the machines follows:
cs918, cs919, cs920, cs921, cs922, cs1417, cs1418, cs1419,
areti, ikaros,cs981, cs982, cs983, cs984, cs985, cs986, cs987,
cs988, cs989,cs990
Use the condor_machines file, on the cluster ssh, to start them all at once

How to change condor configuration on cs919

On cs919 execute the following:

• su - condor
  
• make the changes on ~/condor_config file
  
• execute the command /usr/local/condor/sbin/condor_reconfig
  

Usefull condor commands

• condor_status : shows the status of the condor pool. which machines are idle, claimed etc
  

• condor_q : shows the status of submit jobs on a certain host. (idle, running, etc)
  

• condor_q -global : shows the status of submit jobs on all hosts
  

• condor_restart :restarts the condor pool
  

• condor_reconfig : forces the daemons to read the configuration file and reconfig
  

• condor_off, condor_on : turns on/off the condor daemons
  

Condor Logs files

Logs files are under the same dir (for both master and client nodes) :

• /usr/local/condor/home/log

If condor does not start on client node then.....

• Check the /usr/local/condor/home/log/MasterLog file
• If you get something like "Failed to bind to command ReliSock (Make sure your IP address is correct in /etc/hosts.)ERROR BindAnyCommandPort failed" at line 6008 in file daemon_core.C" then
• Ensure that the machine is registered in ~condor/condor_config at HOSTALLOW_WRITE section
• Check the IP address of client node and check on /usr/local/condor/home/condor_config.local the NETWORK_INTERFACE value. This should be the same as the IP address.

OpenOffice.org 2 and NFS

There is a problem with OpenOffice.org 2 when writing on NFS mounted points that causes the program to freeze. This can be solve by editing the file /usr/lib/openoffice.org2.0/program/soffice and commenting out the lines:

# file locking now enabled by default
#SAL_ENABLE_FILE_LOCKING=1
#export SAL_ENABLE_FILE_LOCKING

How to find NFS version and get server and client activity

Use the command nfsstat -m Prints information about each of the mounted NFS file systems If you execute the command on server, displays statistics kept about NFS client and server activity.

Solaris

How to stop/disable the autofs on Solaris 9

Autofs is running by default on Solaris 8/9.
If you need to stop it execute the command: /etc/init.d/autofs stop

If you need to disable then you have to rename the following files :
/etc/rc2.d/S74autofs (check also all the rcX.d)
/etc/auto_master
/etc/auto_home
/etc/initd/autofs

Also edit the /etc/nsswitch.conf and remove "nis" in the clause "automount"

General

Handling multiple messages in pine.

In order to handle multiple messages at once using pine, you first have to enable the aggregate commands: Setup<S> -> Config<C> and check the enable-aggregate-command-set option as shown in Figure 1

Figure 1

.

This option adds: a Select command (;) to select messages by various criteria (From, Subject, Date, etc); a Select Cur (:) to select the current message; an Apply command (A) to apply commands such as Save(S), to save all Selected messages; and Zoom (Z) to restrict the messages shown in the Folder Index to just the selected ones; and Del (D) to delete all Selected messages.

Open the folder you want to handle and click the semicolon (;) Select the messages you want to handle by any criteria that you like, {e.g.: if you want to select a range of message type (N) and then the range (1-1000) and hit enter} then hit (A) and select the command you would like to apply to them{e.g.: (D) To delete the selected messages (X) after (D) will also expunge the messages}.

VPN

vpn client DNS registration

If you are connected to the vpn through a laptop or desktop that does not have as default domain either the cs.ucy.ac.cy or the in.cs.ucy.ac.cy, then you need to tell the DNS to register the connection using the vpn domain. BEFORE CONNECTING

1. Right click on the Cisco VPN Adapter (Figure 1 Below ) and then on TCP/IP properties (Figure 2 Below )first select Obtain IP automatically and Obtain DNS automatically. Then under Advanced->DNS
2. select Append these DNS suffixes in order
3. under that click on Add button and insert cs.ucy.ac.cy in the widow that will appear
4. check the Use this connection's DNS suffix in DNS registration box (as shown in Figure 2)
5. Check the Register this connection's address in DNS

and then click OK Right click on the connection and click repair or disconnect from the VPN and reconnect. This should fix the problem, and the client will be able to open ssh sessions or other type of connections that demand forward and reverse name resolution.

Alternatively, in case you don't like the mouse clicks, you can use the following command:
netsh interface ip set dns name="<connection name>" source=dhcp register=both
where <connection name> is the name of the VPN connection as seen in the view all connections window

Email

Out of the office or going on vacation

• ssh to any Unix/Linux Machine

First create a file called .vacation.msg Note: Don't miss the "." in front of the filename... Its very important!!!
Write your message in the file (an example of what you can put in the file is shown here.

Example

Dear '$FROM'
I will be away from my office until February 30th, 2007. 
I will read your message regarding '$SUBJECT' when I return on February 31st.

• Then create a file called .forward

The file should have the following line

\username, "|/usr/bin/vacation -t## username"

where username is your login name and ## is the number of days before sending the vacation mesage to the same recipient again.

• Enjoy your vacation
• Once you return back delete the .forward file or move it to a different name to stop sending vacation messages