Using-pepcli.md

@@ -307,6 +307,7 @@ Important flags are:
 - `-C` Column group to list data for. Can be repeated if you want data for more than one column group. There is a special column group `*` that contains all columns.
 - `-c` Specific column to list data for. Can be repeated, and combined with `-C` if you want multiple columns and column groups
 - `-P` Participant group to list data for. Can be repeated if you want data for more than one participant group. There is a special participant group `*` that contains all partipants.
+- `-p` Participant identifier or pseudonym to list data for. Can be repeated if you want data for more than one participant.
 - `-o` Directory to write files to. Default is `pulled-data`.
 - `-f` Overwrite or remove existing data in output directory
 - `-r` Resume an interupted download