To retrieve to list of tables in DB2, you need to use the system tables, and then a little bit of sed. Here is how it goes:
db2 "SELECT tabschema || '.' || tabname FROM syscat.tables" | sed -e '/ //g'
You can redirect this into a file, and you may need to cut off the first few and last few lines. If you only want to get the tables from a given user space:
SELECT tabschema || '.' || tabname FROM syscat.tables WHERE tbspace = 'USERSPACE1';
If you want the list for a specific schema:
SELECT tabschema || '.' || tabname FROM syscat.tables WHERE tabschema = 'MYSCHEMA';
Reference: How to get useful information from the DB2 UDB system catalog