Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: Novice surprise
Message-ID: <11393@jpl-devvax.JPL.NASA.GOV>
Date: 12 Feb 91 00:13:22 GMT
References: <cbhl9z200VsnE1=K1b@andrew.cmu.edu>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 33

In article <cbhl9z200VsnE1=K1b@andrew.cmu.edu> bobg+@andrew.cmu.edu (Robert Steven Glickstein) writes:
: It was two hours of staring at this stupid thing before I realized
: that the problem was this:  The filenames that I was passing as
: arguments happened to begin with a "+".  Since I didn't have
: write-access, I got a "cannot open file" error.  I couldn't figure out
: a way to circumvent this in Perl, so instead of the command-line
: 
:     perlscript +a +b +c
: 
: I used
: 
:     perlscript ./+a ./+b ./+c
: 
: The big question:  What is the *right* way around this problem?

Er, don't use a toy language for a real problem...  :-)

I think that most people avoid the problem by not using filenames beginning
with + or >.  If you really want to write a bulletproof script, you might
put the following before the initial loop:

for (@ARGV) { s#^([^/])#./$1#; s#$#\0#; }
while (<>) {...

In general, filenames starting with + aren't quite as dangerous as those
starting with -, but there are some programs that use + to introduce
switches, so it's probably a bad idea.  You can't, for example, say

    sort +a +b +c

Just don't create a file called -rf.  :-)

Larry