filter prefixing each line with a timestamp, translated from awk and posted to comp.lang.scheme.scsh in 1997-05 by Olin Shivers
typical system script posted to comp.lang.scheme.scsh in 2000-04 by Olin Shivers
posted to comp.lang.scheme.scsh in 1997-09 by Dirk Bernhardt
posted to gmane.lisp.scheme.scsh in 2003-11 by Zhao Wei
