subroutine char Str_arg int COLOR  char F_KEEP
!show vari F_KEEP
key old sele all end
read file Str_arg coor pdb
if ( F_KEEP .ne. "keep" ) then
 rena segm BACK sele .not old end
end_if
set vari SEGMENTS char segm select .not old end
<>utils/calculate_bonds_segm.com SEGMENTS
!<>cmds/re_image_col.cmds SEGMENTS  COLOR
image group name BACKGROUND
image sele segm name SEGMENTS .a atom name C N CA end col COLOR bond
image cent calc sele .not old end
if ( F_KEEP .ne. "keep" ) then
 delete atom sele .not old end
 else
 set vari WORK_SEGM char global segm sele segm name WORK_SEGM  SEGMENTS end
 end_if
image from erase
return