.if t .if !\nv .tl '--''--' .ps20 .sp 4.25i .ft B .ce BERKELEY UNIX PROGRAMMER'S MANUAL .sp |5i .\" .ft I .ps 16 .vs 20 .ce PDP\-11 Version 2.9 .ce Seventh Edition, Volume 1 .ps10 .vs 12 .sp |7.5i .ce .ft I April, 1983 .sp |8.5i .ft R .ce 5 Second Berkeley Software Distribution Computer Science Division Department of Electrical Engineering and Computer Science University of California Berkeley, California 94720 .bp