Not sure how much of a beginner question this is. I've been searching
mail archives and can't find anything about it. I've embarrassed myself
by giving advice based on my reading of the Camel book, but the advice
doesn't work.
In the "Camel" book "Programming Perl", Chapter 19 is a chapter on using
the Perl command line. One example there is to use
#!/bin/sh -- # -*- perl -*-
eval 'exec perl -S $0 ${1+"$@"}'
if 0;
The explanation says that the presence of -*- perl -*- on the
shebang line causes perl not to pay attention to that line,
but does cause emacs to treat the script as a perl file.
But we'd like to be able to use sh or bash to locate one of
several okay versions of Perl. The path to Perl differs depending
on what installation it is run in. We cannot just use the user's path
or environment, because these scripts are used in strictly-managed
configuration management/QA/build/release processes. Each one has
to use a particular version and installation of Perl and no other.
We have got something that works quite well, except that an emacs
user complains that emac doesn't recognize the script header as Perl,
and instead provides shell highlighting instead of Perl highlighting.
Hence my question is, how do we accommodate the emacs user?
The following code works well (pathname specifics changed for
confidentiality):
#!/bin/bash -- #
perl1="/path1/perl"
perl2="/path2/perl"
if [ -x $perl1 ]
then
perl=$perl1
elif [ -x $perl2 ]
then
perl=$perl2
else
echo Unable to find perl, contact local suport person
exit 2
fi
exec $perl -x $0 "$@"
#!/dummydir/perl -w
$myname=`basename $0` ; chomp $myname;
$mydir=`dirname $0` ; chomp $mydir;
$mydir=`(cd $mydir; pwd)`; chomp $mydir;
print "I am $myname in directory $mydir\n";
print "My options are:\n";
for $a ( @ARGV ) {
print "$a ";
}
$onlyonce=1;
print "\n";
exit 0;
---------------------------------------
Perl gets control, skips the bash code, finds the second shebang line,
honors the -w flag, and runs the script.
But if we change the initial shebang line to
#!/bin/bash -- # -*- perl -*-
then Perl does not skip the bash code, and gives lots of error messages.
So it looks like the advice in the Camel book is no good. Either that
or I've forgotten how to read a technical manual. Can someone help?
thanks,
--Marilyn Sander
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
<http://learn.perl.org/> <http://learn.perl.org/first-response>
