FASTA format

In bioinformatics, long character strings are often encoded in a format called FASTA. A FASTA file can contain several strings, each identified by a name marked by a '>' character at the beginning of the line.

FASTA format is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Write a program that reads a FASTA file such as:

>Rosetta_Example_1
THERECANBENOSPACE
>Rosetta_Example_2
THERECANBESEVERAL
LINESBUTTHEYALLMUST
BECONCATENATED

And prints the following output:

Rosetta_Example_1: THERECANBENOSPACE
Rosetta_Example_2: THERECANBESEVERALLINESBUTTHEYALLMUSTBECONCATENATED