phipsi: print φ, ψ, ω and χ angles of a protein

phipsi [ input-file ]

The phipsi command reads the input Protein Data Bank format file (or standard input if omitted), and, assuming file contains the the atomic coordinates of a protein, computes and prints the φ, ψ, ω, χ₁ and χ₂ dihedral angles to standard output.