Given a source/target pair of selected meshes, selects vertices on the source mesh that are near the target mesh.:

zSelectVerticesByProximity -h;
       // Result: Flags:
       zSelectVerticesByProximity ...
       -h   -help                           <n/a>          this message
       -r   -radius                         <float>        Is used to set the radius used for proximity detection.
       Select the meshes that you would like to compare and execute:
       zSelectVerticesByProximity -r 0.5;
       If the "-r" flag isn't used; a value of 0.25 is used as the default. //