xplor it is :
structure @native.psf end
dynamics analysis
pick dihedral
( residue 19 and name c and segid="A ")
( residue 20 and name n and segid="A ")
( residue 20 and name ca and segid="A ")
( residue 20 and name c and segid="A ") geometry
asci=false
input=fitted.dcd
begin=0 skip=1 stop=2000000
output=phi_20A.list
end
stop
structure @native.psf end
dynamics analysis
pick dihedral
( residue 36 and name n and segid="A ")
( residue 36 and name ca and segid="A ")
( residue 36 and name c and segid="A ")
( residue 37 and name n and segid="A ") geometry
asci=false
input=fitted.dcd
begin=0 skip=1 stop=2000000
output=psi_36A.list
end
stop