[procedure] read-string num [port]

Chicken: reads up to num characters or to encounter EOF from port.

Gauche has the same function in module text.parse.

Scsh allows a file descriptor in place of a port. See also read-string!, read-string/partial?

[procedure] read-string [port]

Bigloo: lacks num argument. Reads everything upto EOF. This version has similar functionality as port->string which can be found in several implementations.