Bond variations from the trajectory

Dear Lammps Users,

I have a molecular dynamics simulation done for a system
where part of the molecule undergoes elongation during the simulation
window and other remains same or decreased.

I can calculate the bond length for each structure,
and I can calculate the standard deviation.
But this is going to be a hard procedure.

Does some one have any idea on how this problem
can be addressed. If so can you please share me your views.

Thanks in advance.