Tonight I created a example on how to use a Linux/UNIX command to return data as performance data in OM12. In this example we build a rule that count files in a folder and returns it as performance data.

1. In the Operations Manager console, navigate to Author/Management Pack Objects/Rules
2. Right-click rules and create a new Rule, select Collection Rules/Probe Based/UNIX/Linux Shell Command (Performance) rule
3. Select a management pack
4. General, input a name and a rule target. For example “Field – X plat – Number of files” as name and “SUSE Linux Enterprise Computer” as monitor target
5. Schedule, select how often you want the rule to run the command, for example every 15 minute
6. Shell Command Details, input the script you want to use. The command can be a path to a binary or script file or a single-line shell command. In this example we can the following command to count files in the /tmp folder
   find /tmp | wc -l
7. Filter Expression, use default settings and click Next
8. Performance Mapper, input name of object, counter and instance, for example
   Object: Folder Management
   Counter: Number of files
   Instance: /tmp
9. Click Create and your rule is ready!

You can now navigate to a performance view and show the data collected by the rule (might need to wait some minutes depending on your rule settings)