I will gladly give you that infromation. You can pipe the output of any file through grep to limit the output to only the lines that contain your chosen text.

So in my example I want to see all applications that are using the file /usr/lib/libXrender.so.1.3.0

matt:~$lsof|grep "/usr/lib/libXrender.so.1.3.0"

dzen2     2519       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

chrome    2692       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

chrome    2700       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

chrome    2901       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

chrome    2913       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

GoogleTal 2916       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

konsole   3207       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

blender   3666       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

kdeinit4  3908       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

klauncher 3910       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

kded4     3913       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

knotify4  3924       matt  mem       REG        8,5    30712 2532691 /usr/lib/libXrender.so.1.3.0

This is listing the applications in the first column, the username in use in the third column and the file being used in the last column. If you want to learn more about the uses of lsof or grep you can consult their man pages by typing man followed by the application name.