Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!mcgill-vision!snorkelwacker!usc!ucsd!sdd.hp.com!zaphod.mps.ohio-state.edu!uwm.edu!ogicse!schaefer
From: schaefer@ogicse.ogi.edu (Barton E. Schaefer)
Newsgroups: comp.lang.perl
Subject: Re: Novice Question: How is -e supposed to work?
Message-ID: <11415@ogicse.ogi.edu>
Date: 16 Aug 90 15:14:08 GMT
References: <1990Aug16.070010.26529@morrow.stanford.edu>
Organization: Oregon Graduate Institute (formerly OGC), Beaverton, OR
Lines: 32

In article <1990Aug16.070010.26529@morrow.stanford.edu> whenry@lindy.stanford.edu (homo obsolescensis) writes:
} 
} I am having trouble using the -e switch.  the man
} pages give the following example: (lets call this file "go")
} 
} 	#!/usr/bin/perl -pi.bak
} 	s/foo/bar/;
} 
} and intimate that the result of running go  on file bas will be a
} changed file bas.
} 
} however, when I try any of the following, the results are the same as
} if only the -p switch were set.  that is, the changes are printed to
} the screen only, not to the original file.

I'm curious what this has to do with the -e switch (as mentioned in
the subject header).  As speculation, I'll bet that you aren't really
using a file named "go" containing the above two lines, but rather
you are trying to use

	perl -pei.bak 's/foo/bar/;' < bas

Even though that looks sensible to me, it isn't sensible to perl.  (Why
not, Larry?  Is it that tough to parse?)  When perl gets to the 'e' in
"pei.bak" it quits reading from that argument and skips ahead to the
expression.  The "i.bak" is therefore never seen.  Use

	perl -pi.bak -e 's/foo/bar/;' < bas

and everything will be fine.
-- 
Bart Schaefer						schaefer@cse.ogi.edu