# Define the regular expression series of a process class

Complete the previous section, and then follow these steps to create the series of regular expressions that define a process class, and generate process sets.
1. In the list area of the tree view, select DB daemons.
2. In the Description field, enter Database daemons.
3. In the Include processes like field, replace DB daemons with a Python regular expression that selects the database processes. For example, ora_[^_]{4}_orcl. The example regular expression selects all of the processes in the sample process instance list.
4. In the Exclude processes like field, enter a regular expression to remove processes from the results of the preceding regular expression. The default entry excludes common user commands. The default entry does not exclude any of the processes in the sample process instance list.
5. The next two fields, Replace command line text and With, work together to simplify the names of process sets.
• In the Replace command line text field, enter a regular expression containing one or more pattern groups.

• In the With field, enter replacement text, along with the sequence number of one or more of the pattern groups defined in the previous field.

For example, to create four pattern groups for database processes, enter the following regular expression in the Replace command line text field:

^(ora_)([a-z])(.{4})(orcl)

To use two of the pattern groups in the replacment text, enter the following text in the With field:

DB [\4] daemons starting with [\2]

Each unique replacement generated by the combination of the text plus the inserted pattern sequences becomes a process set. In the case of this example, pattern group 4 does not vary, but pattern group 2 does. So the number of process sets generated by this class will equal the number of unique alphabetic characters found in the first position after the first underscore.

6. Click Save.