parmstrip
Remove selected atoms from topology.
parmstrip <mask> [parm <name> | parmindex <#> | <#>]
Strip atoms in <mask> from specified topology (by default the first topology loaded). Note that unlike the strip Action, this permanently modifies the topology for as long as cpptraj is running, so this should not be used if the topology is being used to read or write a trajectory via trajin/trajout. This command can be used to quickly created stripped Amber topology files. For example, to strip all residues name WAT from a topology and write a new topology:
parm mol.water.parm7 parmstrip :WAT parmwrite out strip.mol.parm7