Working with regular expressions

In this last example, you specified the files with a wildcard, which was basically a regular expression. A regular expression is much more than specifying the known wildcards ? or *.
In the following table, you have some examples of regular expressions, which you may use to specify filenames. The Example column refers to the sample files in the tutorial:

Note that the * wildcard does not work the same way as it does on the command line. If you want to match any character, the * has to be preceded by a dot.

This was the first time that you faced a regular expression in PDI; however, they are used in a lot of places, both in jobs and transformations. If you are not used to them, it is highly recommended that you learn at least the basics about the subject.
Here you have some useful links in case you want to know more about regular expressions:

• Read about regular expressions at http://www.regular-expressions.info/quickstart.html
• Read the Java regular expression tutorial at http://java.sun.com/docs/books/tutorial/essential/regex/
• Read about Java regular expression pattern syntax at https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html