proc Echo;      \Echo line of characters from file to screen
int Ch;
def LF=$0A, EOF=$1A;
[loop   [Ch:= ChIn(3);
        case Ch of
          EOF:  exit;
          LF:   quit
        other ChOut(0, Ch);
        ];
];

int Ch;
[FSet(FOpen("fasta.txt", 0), ^i);
loop    [Ch:= ChIn(3);
        if Ch = ^> then
                [CrLf(0);
                Echo;
                Text(0, ": ");
                ]
        else    ChOut(0, Ch);
        Echo;
        ];
]