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From: wcw@psuhcx (William C Ward)
Newsgroups: comp.cog-eng,comp.unix.xenix,comp.unix.wizards
Subject: Re: Request for human interface design anecdotes (and a cure?)
Message-ID: <3103@psuvax1.psu.edu>
Date: Mon, 16-Nov-87 23:31:28 EST
Article-I.D.: psuvax1.3103
Posted: Mon Nov 16 23:31:28 1987
Date-Received: Thu, 19-Nov-87 01:58:23 EST
Sender: netnews@psuvax1.psu.edu
Reply-To: wcw@psuhcx (William C Ward)
Organization: Penn State University, University Park, PA
Lines: 34
Xref: mnetor comp.cog-eng:292 comp.unix.xenix:1158 comp.unix.wizards:5487

In article <1689@rayssd.RAY.COM> dhb@rayssd.RAY.COM (David H. Brierley) writes:
>If users removing all of their files by inadvertently typing "rm *" is
>a habitual problem at your site, why not make the command default to
>interactive mode? 

The rm * disaster catches not only the absent-minded, but also the hasty
and uncoordinated.  I once mistyped a command like:
	rm *&foo
instead of rm *foo (*& is a double-strike of adjacent keys!) and the
machine obediently and hastily removed all files in the directory via a 
background process.  My screams were audible many doors down the hall as
I looked helplessly at the screen.

What I have done to lessen future disasters of this kind is to insert the
following crontab entry for other users:
# Keep second copies of recent source files (*.c, *.f, *.h) in /tmp
30 * * * * nice -10 find /usr/usr -mtime -1 -name *.[cfh] -exec cp {} /tmp \;
# Get rid of old /tmp files
0 2 * * * find /tmp -atime +4 -exec rm -f {} \;

If incremental dumps are done at least every 4 days, this means that
most source development work that can be lost is one hour's worth, if
your disk doesn't crash entirely.  The extra load on a small system 
with a little extra space and 10 or 20 users is pretty negligible, since
only files which have been modified in the last hour are copied.  If
security is a concern, the backup files (owned by root) can be set to
600 mode.  Moreover, it protects against `generic' disasters (rm, cp,
cc -o, or foolish edits).

This has saved me more than once now!
Bill Ward			Bitnet:	WCW@PSUECL
Noise Control Laboratory	UUCP:	{gatech,rutgers,..etc.}!psuvax1!ncl!wcw
The Penn. State University	USnail:	157 Hammond Bldg.;
Fone:		(814)865-7262	University Park, PA 16802