How to find the version of .pls file in linux?

To find the versions of .pls,.fmx,.xdf files?

strings -a $XX_TOP/filename | grep '$Header';

1)for example if i want to find the version of aptxdefb.pls file
  it is related to $APPL_TOP so connect to cd $APPL_TOP/patch/115/sql  and check the file aptxdefb.pls exists are not.[by using ls -ltr aptxdefb.pls]

        [applmgr1@apps appl]$ cd $AP_TOP

         

        [applmgr1@apps 12.0.0]$ cd patch/115/sql/

         

         [applmgr1@apps sql]$ ls -ltr aptxdefb.pls

         -rwxr-xr-x 1 applmgr1 dba1 19571 Jan  3  2007 aptxdefb.pls

         [applmgr1@apps sql]$ strings -a aptxdefb.pls | grep '$Header';

         /* $Header: aptxdefb.pls 120.11 2005/08/04 04:44:25 hongliu ship $ */

for finding the versions of fmx file is also same.

            strings -a APXINWKB.fmx | grep '$Header';