Syntax:

chain( neta )

The 'chain' command provides an easy was of specifying a linear sequence of atoms from the current atom forward. Within the bracketed part, a sequence of connections are listed in the order in which they are to appear. Atoms in the chain are specified in the same way as other connections (e.g. '-C(nbonds=2)') but should not be separated by commas. The repeat keyword n may also be specified at some point in the bracketed part to define that more than one of the defined chains is required. Note that, if all atoms specif ied for the chain are matched, but the actual chain in the model is longer, a positive match will be returned. Thus, it is usually a good idea to define the last atom in the chain more explicitly to prevent false matches.

For example: