FAQforge provides answers for frequently asked questions for the Linux-, MAC and Windows operating systems.
How to change the update frequency in Microsoft security essentials
Microsoft security essentials is the free antivirus software from Microsoft for Windows 7. Unlike other antivirus tools which update their signatures every few hours, Microsoft security essentials is updating its antivirus signature database only once in 24 hours. But the update frequency can be changed in the Windows regestry and the following tutorial will show you how.
1) Open the registry editor by executing the following command on the windows console
regedit
2) Go to the key:
HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Microsoft Antimalware/Signature Updates
Then click on “Signature Updates” > “Permissions” >”Advanced” and go to the “Owner” Tab. There click on the administrator group and click OK. Now your back in the “Permissions” Window, select the “Administrators” Group and enable the checkbox which is labeled with “Full Control”.
You have changed the permoissions now so that your administrator user can edit the keys. The next step is that you doubleclick on “SignatureUpdateInterval”, select “decimal” and enter the update interval. The interval is set in hours from 1 to 24.
For security reasons, you should then change the permissions back from “Administrator” group to “System” group and close the registry editor.
Microsoft security essentials will now update its signatures in the interval you set in the registry.
Please be aware that a MSE update will reset the interval back to 24 hours. As a alternative approach of updating the signatures, you can create a scheduled task which executes the command:
cd “C:\Program Files\Microsoft Security Client\Antimalware”
MpCmdRun.exe -SignatureUpdate
The commnd should be executed as “SYSTEM” user.
How to Configure a Mail Account in Thunderbird on Linux
To add a mail account to your Thunderbird, go to Edit > Account Settings…
and hit the Account Actions button beneath the menu on the left.
Select Add Mail Account… and enter the name that will be shown to others, the email address that you want to add to Thunderbird and its password.
Hit Continue and Thunderbird should automatically search for your address on the given server. If it is not found you can also configure it manually. Select the IMAP radiobox as recommended to be able to view your mail on multiple computers and hit Create Account.
You should now be able to access your email account via Thunderbird. If this is still not the case you may have to complete your account name so that it is identical with your email address.
How to connect to an SSH-Server
To connect to a system’s terminal with a static network IP and an SSH-Server installed, open a terminal and enter following command, exchanging the network IP with the one of your SSH-Server:
ssh root@192.168.0.110
Enter the target SSH-Server’s root password afterwards. To exit the server’s shell, enter
exit
How to Block Web Pages (Linux Mint 11)
To block web pages on Linux Mint, there is a simple tool in your Control Center. Go to Menu > Control Center > System > Domain Blocker and you will be asked for your password. A plain window with just a few buttons will appear afterwards.
To add web pages to the blocking list, click on Add and type in the (un-)desired page. It may occur that you have to enter it two times, one with www. and one without www..
To adopt the changes restart your browser and the entered web page should no longer be available.
How to Create New Shellscripts
This guide explains how you can create new shellscripts to execute in a terminal (I am using Linux Mint 11). Your scripts are usually stored in /bin and /usr/bin, however the sh file which we are going to use is located in /bin, so we are going to create the script there. Open a terminal and become root with
su
Now create a new text document in /bin and make it writable and executable:
touch /bin/newscript
chmod 777 /bin/newscript
Open the newly created file with a text editor and write the following code in the first line of the file:
#!/bin/sh
Save the file now. Through this line it has become a script executed with the default shell, although it has no content yet. However you can either write your own script into it using Shell Script or use it to combine scripts you execute together a lot to save time.
How to Kill Processes on UNIX Based Operating Systems
This guide explains how to kill processes on Unix based operating
systems.
To kill a process you need to know its Process ID (PID). To find out that, open a terminal and enter
ps -e
The list of processes has two columns that are important for you, which are PID and CMD. CMD gives you the name of the process whereas PID gives you the ID. Search the list for the process you want to kill and enter
kill -9 PID
Replace PID with the PID of the process you want to kill. This procedure is similar to the one of Windows’ Task Manager.
Tutorial: take a screenshot on a iPad 2
This tutorial explains the process to take a screenshot from your iPad or iPhone screen. There is no app required to take the screenshots.
1) Navigate to the screen that that shall be saved as screenhot. In my example I will take a screenshot of the home screen.
2) Press the “Power” button (in the upper right corner of the iPad) and the “Home” button (in the middle of the lower bar of the iPad) simultaniously.
You will hear a “camera click” and the screen will fade to white for a second when the screenshot is taken. The screenshot is saved into Photos folder on the iPad.
To view the screenshot, open the “Photos” app:
and tap on the photo.
The easiest way to transfer the screenshot to your desktop PC or MAC is to send it by email. Tap on the Icon in the upper right corner of the screen:
and select “Email Photo”:
This tutorial works on iPad and iPad 2 and iPhone.
Redirect http requests to a new folder with apache rewrite rules
When you reorganize the structure of a website, you might want to redirect requests to files in a old folder to a new one without loosing the pagerank. In this example, I will redirect all requests from directory “olddir” to directory “newdir”, so that requests like http://www.yourdomain.tld/olddir/page.htm get redirected to http://www.yourdomain.tld/newdir/page.htm without loosing the Google pagerank of the pages.
The following rewrite rules can be added into a .htaccess file in the website directory or in the vhost configuration.
RewriteEngine on
RewriteRule ^olddir/(.*)$ newdir/$1 [R=301,L]
This rewrite rule redirects automatically all requests to pages or subdirectorys of “olddir” to the same page or subdirectory in “newdir”.
Reduce load of backup scripts with nice and ionice
Runing a nightly backup script on a server system like a webhosting server can produce high load and longer latencys for other processes, e.g. HTML or .php pages load slow during backup because the backup script takes too much I/O or CPU resources.
On Linux systems there are two shell utilitys available to set the I/O and CPU Scheduling for a appliaction or script. The utilitys are named nice and ionice.
Reduce the I/O priority of the script “/usr/local/bin/backup.sh” so that it does not disrupt other processes:
/usr/bin/ionice -c2 -n7 /usr/local/bin/backup.sh
The -n parameter must be between 0 and 7, where lower numbers mean higher priority.
To reduce the CPU priority, use the command nice:
/usr/bin/nice -n 19 /usr/local/bin/backup.sh
The -n parameter can range from -20 to 19, where lower numbers mean higher priority
Nice and ionice can also be combined, to run a script at low I/O and CPU priority:
/usr/bin/nice -n 19 /usr/bin/ionice -c2 -n7 /usr/local/bin/backup.sh
How to enable time synchronisation between OpenVZ host and guest system
If you want to set the time in a OpenVZ Guest automatically, execute the following command on the host system:
vzctl set 101 –capability sys_time:on –save
and restart the guest system:
vzctl restart 101
101 is the ID of the container and has to be changed to match the ID of your OpenVZ VM.
Thanks to PlanetFox for this FAQ.