Using Pipelines to Select Classes

Using the Unix find command to select the class files to process, provides infinite flexibility.

You can specify a range of modification times for the files. As an example, the following command will print the metrics of the class files modified during the last week.
```
find build -name '*.class' -mtime -7 -print | java -jar /usr/local/lib/ckjm.jar
```
You can filter out specific patterns, either with the GNU find's regular expression options, or by piping its results through grep. As an example, the following command will not print metrics for internal classes (their name contains a $ character).
```
find build -name '*.class' | fgrep -v '$' | java -jar /usr/local/lib/ckjm.jar
```
You process contents from several directories. As an example, the following command will process the class files located in the build and lib directories.
```
find build lib -name '*.class' -print | java -jar /usr/local/lib/ckjm.jar
```