.sh GSI Simulate Model 37 Teletype facilities on GSI-300, DASI and other Diablo-mechanism terminals. .op Gives half-line and reverse platen motions. .op Approximates Greek letters and other special characters by overstriking. .op Usable as a filter. .sh COL Canonicalize files with reverse line feeds for one-pass printing. .op Usable as a filter.