learn.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)learn.1	8.1	9/11/90
.TH learn 1 "" "" Unsupported
.SH Name
learn \- computer aided instruction about UNIX
.SH Syntax
.B learn
[
.BI \- directory
]
[ \fIsubject\fP [ \fIlesson\fP ] ]
.SH Description
The
.PN learn
command gives computer aided instruction courses and
practice in the use of UNIX, the C Shell,
and the Berkeley text editors.
To get started simply type
.BR learn .
The program will ask questions to find out what
you want to do.
Some questions may be bypassed by naming a
.IR subject ,
and more yet by naming a
.IR lesson .
You may enter the
.I lesson
as a number that
.PN learn
gave you in a previous session.
If you do not know the lesson number,
you may enter the
.I lesson
as a word, and
.PN learn
will look for the first lesson containing it.
If the
.I lesson
is `\fB\-\fP',
.PN learn
prompts for each lesson;
this is useful for debugging.
.PP
The
.IR subject s
presently handled are
.if n .sp 1v
.if t .sp .5v
.nf
           files
           editor
           vi
           morefiles
           macros
           eqn
           C
.fi
.PP
There are a few special commands.
The command `bye' terminates a 
.PN learn
session and `where' tells you of your progress,
with `where\0m' telling you more.
The command `again' re-displays the text of the lesson
and `again\0\fIlesson\fP' lets you review
.IR lesson .
.SH Options
.TP 15
.BI \- directory
Allows one to exercise a script in
a nonstandard place.
.SH Restrictions
The main strength of
.PN learn,
that it asks the student to use the real UNIX,
also makes possible baffling mistakes.
It is helpful, especially for nonprogrammers,
to have a UNIX initiate near at hand during the first
sessions.
.PP
Occasionally lessons are incorrect, sometimes because the local version
of a command operates in a non-standard way.
Such lessons may be skipped with the `skip' command,
but it takes some sophistication to recognize
the situation.
.PP
To find a
.I lesson
given as a word,
.PN learn
does a simple
.MS fgrep 1 
through the lessons.
It is unclear whether this sort
of subject indexing is better than none.
.PP
Spawning a new shell is required for each of many
user and internal functions.
.SH Files
.nf
/usr/lib/learn	subtree for all dependent directories and files
/usr/tmp/pl\(**	playpen directories
.SH See Also
csh(1), ex(1)