“segment” selects atoms based on their assigned chain, which is a four-letter code.

segment segment-identifier-pattern
segi segment-identifier-pattern
s. segment-identifier-pattern

indicate segment 1HPV
indicate segi ab*
indicate s. liga+prot

A blank or undefined segment identifier is entered as two apostrophes.

segment ''

The macro equivalent is segment-identifier-pattern///.

indicate cpy1///
indicate seg1+seg3///

bysegment

Selections | Selection Macros | Segment Concept