.RP
.TM "79-1274-xx 79-1273-yy" 39199 39199-11
....ND June 18, 1976
....TM "76-1274-6 76-1273-5" 39199 39199-11
.TL
LEARN \(em Computer-Aided Instruction on UNIX
.br
(Second Edition)
.AU "MH 2C-518" 6021
Brian W. Kernighan
.AU "MH 2C-569" 6377
Michael E. Lesk
.AI
.MH
.OK
CAI
.AB
.PP
This paper describes the
second version of the
.I
learn
.R
program for interpreting CAI
scripts on
the
.UX 
operating system,
and a set of scripts that provide a computerized introduction
to the system.
.PP
Six current scripts cover basic commands and file
handling, the editor, additional file handling commands, the
.I
eqn
.R
program for mathematical
typing,
the ``\-ms'' package of formatting macros,
and an introduction to the C programming language.
These scripts now include a total of
about 530 lessons.
.PP
Many users from a wide variety of backgrounds have used
.I learn
to acquire basic UNIX skills.
Most usage involves the first two scripts,
an introduction to
.UX
files and commands, and
the
.UX
editor.
.PP
The second version of
.I learn
is about four times faster than the previous one
in CPU utilization,
and much faster in perceived time
because of better overlap of computing and printing.
It also requires less file space than the first version.
Many of the lessons have been revised;
new material has been added to reflect changes
and enhancements in 
.UX
itself.
Script-writing is also easier
because of revisions to the script language.
.AE
.CS 11 2 13 4 0 0