Year: 2014

Use Java 6 and Java 7 on (X)ubuntu Eclipse

Install both Java versions

Check active version

Check installed versions

In Eclipse go into
Project > Properties > Java Build Path > Add Library > JRE System Library > Alternate JRE

If your Java is not in it

  • Click on Installed JREs
  • Click Add
  • Click Standard VM
  • Choose Directory containing Java 6 (/usr/lib/jvm/java-6-openjdk-i386)


Shell Script – check if another instance of same script is running


Fix strange behaviour of OR operator in Perl

Using the OR operator in Perl while doing an assignment is not a good idea. The Perl documentation [1] states that the precendence of OR is lower that of ||. If you are not aware of this the results will leave you scratching your head. Look at the examples below that should all return the same. more

Count number of files in directory and subdirectories

Count all files in current path including sub directories

Count all pdf files in current path including sub directories



Replace spaces in file names by underscores on Linux console

Replace spaces in all file names in folder test/ by underscores:


Remove BOM while reading file with Perl

Just remove the BOM from the first line a while readout


Count elements of multi-dimensional array in Perl