Category Archives: tips

Schedule meetings automatically into Google Calendar with Doodle or Calendly

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doodle.com is a well known page for scheduling meetings or making decisions. Its calendar integration is probably less known. Doodle can export a calendar with the dates you have chosen in order to remind you to keep them blocked. When a date is fixed for a query, doodle releases the other dates. You can also add your calendar to doodle to see your availabilities right in the doodle calendar and to use such features as autofill.

If you look for something else, calendly.com is another free service that provides an interface for others to schedule a meeting with you. Dates with concurring events in your Google calendar are automatically blanked out.

 

Use TortoiseSVN without Passwort

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Tortoise SVN has an option for saving authentication, but it does not work for SVN. In order to save the authentication, go to Tortoise settings, for example by right clicking in the Windows Explorer and then selecting Tortoise > Settings. In the settings window, select Network. Then add the path to Tortoise Plink (it is in the “bin” folder of the Tortoise installation) and add an option for a username and password using options -l and -pw.

For example:
“C:\Program Files\TortoiseSVN\bin\TortoisePlink.exe” -l foo -pw bar

 

Recover webpages from your browser cache

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Think of the following situation: The database of your Wiki just crashed, you have a backup from a couple of days ago, but what about the pages that have been edited since then?

There is hope, most likely your browser has cached some of the files when you viewed them the last time.

Very important!
Don’t try to access the page because this will overwrite the cached contents.

To recover the cached pages follow these steps:

Firefox:

  1. Go into offline mode by clicking the hamburger icon, developer tools and work offline
  2. Open the page about:cache
  3. Click on “List Cache Entries”
  4. Search for the page you want to recover
  5. Click on the link, this leads you to a page with the hexdump of the compressed file entitled “Cache entry information”
  6. Click on the link to the page here, the page opens with the cached contents, including images
  7. Save your page

Repeat this from step 2 for every page you are interested in. Go back to online mode (hamburger icon, developer tools and uncheck work offline) when done.

Chrome:

  1. Open chrome://cache
  2. Search for the page you want to recover
  3. Click on the link, this leads you to a page with the hexdump of the compressed file
  4. Select all on this page (Ctrl + A) and copy it to the clipboard (Ctrl + C)
  5. Go to this page http://www.sensefulsolutions.com/2012/01/viewing-chrome-cache-easy-way.html
  6. Paste the contents into the textbox on the page
  7. Click “Go”
  8. Click on the link under “Results” to download the cached file. Some browsers block the download of html files because of security concerns, in this case go to downloads and explicitely allow the download of this file

Repeat this for every page you are interested in.

You are welcome.

Avoid distracting advertisements

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Avoid distracting advertisements on your browser and Skype with the following three tips (they can be applied independently):

    • Install an Ad-blocker for your web browser. Adblock Plus works very well. Some pages block their content if you have an adblocker installed. Therefore, Adblock Plus can be quickly deactivated/activated with a middle mouseclick on the symbol.
    • Deactivate Criteo: Criteo is using tracking cookies to present personalized advertisement. This page explains how to block Criteo cookies
    • Block advertisement in Skype by adding Skype to the restricted internet sites: WinKey+R > inetcpl.cpl > Security > Restricted Sites > Sites and then add https://apps.skype.com to the list

You are welcome!

Turn off ligatures in LateX

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Latex ligatures make a fine typesetting, but sometimes you might want to turn them off — for example if people should be aber to copy the text from the pdf document or if you need to export the pdf to a doc.

You can turn off ligatures with the following commands in the preamble of the Latex document:

\usepackage{microtype}
\DisableLigatures{encoding = *, family = * }

Missing fonts when starting X-application on Linux

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Recently, I got the following error message when I tried to start an X-application under Linux:

Some fonts seem to be missing in your system, you should install either xfonts-100dpi or xfonts-75dpi and then restart Xorg to get xboard running.

I got this error message despite having the packages xfonts-100dpi and xfonts-75dpi installed. After scratching my head for some time I found the problem: I was running the application via ssh with X-forwarding from a Windows PC. And the Xserver was actually running on Windows, namely the Xming application.
The problem was quickly fixed by downloading the font packages from the Xming page.

How does a computer get infected with a virus or spyware?

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Unfortunately, it became quite easy nowadays to infect your computer with malware:

  1. Accepting some plug-in or toolbar installation
  2. Opening email attachments “thesisgenerator.exe”
  3. Not running the latest updates on the operating system, the browser, etc.
  4. Installing software or media from unknown sources
  5. Running your system without a firewall

Sometimes, webpages try to scare users to install a trojan. For example, there exists a trojan version of the program MacSweeper, which promises to clean your system 😛

More on the topic: http://www.computerhope.com/issues/ch001045.htm

How to test the thread limit on Linux

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/* compile with: gcc -pthread -o thread-limit thread-limit.c */
/* originally from: http://www.volano.com/linuxnotes.html */

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <stdlib.h>

#define MAX_THREADS 100000
int i;

void run(void) {
char c;
if (i < 10)
printf(“Address of c = %u KB\n”, (unsigned int) &c / 1024);
sleep(60 * 60);
}

int main(int argc, char *argv[]) {
int rc = 0;
pthread_t thread[MAX_THREADS];
printf(“Creating threads …\n”);
for (i = 0; i < MAX_THREADS && rc == 0; i++) {
rc = pthread_create(&(thread[i]), NULL, (void *) &run, NULL);
if (rc == 0) {
pthread_detach(thread[i]);
if ((i + 1) % 1000 == 0)
printf(“%i threads so far …\n”, i + 1);
}
else
printf(“Failed with return code %i creating thread %i.\n”,
rc, i + 1);
}
exit(0);
}

Additional information

If you are an administrator of a server, you can configure various limits in /etc/security/limits.conf