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New to Perl and stuck...Help

Thu, 18 Dec 2003 13:11:13 -0700

This message was edited by mikeruth at 2003-12-18 13:12:55

This message was edited by mikeruth at 2003-12-18 13:12:10

I am on my second day of Perl programming and I am stuck. The program
below will read a one line, 1 to 2 M file, test it, and, print some counts to another file. I cannot get past the open...infile.

Help! I need to get this done soon (and with "use strict").

Where did all of my spaces go???

========================= The Code ===========================

#!/opt/utils/5bin/perl5.001 -w

# We have two versions. Make sure to use the lastest.

require 5.001;
use strict;

if ( @ARGV < 2 )
{
die "\nUsage: $0 <infile>\n\nStopped";
}

my $infile = shift @ARGV;
my $outfile = shift @ARGV;

open( my $infile_handle, "< $infile" ) or
die "\nCan't open input file \"$infile\".\n",
"Error: $!.\n",
"Stopped";

open( my $outfile_handle, "> $outfile" ) or
die "\nCan't open output file \"$outfile\".\n",
"Error: $!.\n",
"Stopped";

my $text = join( '', <$infile_handle> );
my $test_len = length( $test );
print "\n" , $test_len, "\n";

close $infile_handle;

chomp $text;

#
# process the line and print results...
#

close $outfile_handle;

exit ( 0 );

Re: New to Perl and stuck...Help

Thu, 18 Dec 2003 13:53:08 -0700

: I am on my second day of Perl programming and I am stuck. The ]
: program below will read a one line, 1 to 2 M file, test it, and,
: print some counts to another file. I cannot get past the
: open...infile.
:
: Help! I need to get this done soon (and with "use strict").
:
: Where did all of my spaces go???
:
: ========================= The Code ===========================
:
: #!/opt/utils/5bin/perl5.001 -w
:
: # We have two versions. Make sure to use the lastest.
:
: require 5.001;
: use strict;
:
: if ( @ARGV < 2 )
: {
: die "\nUsage: $0 <infile>\n\nStopped";
: }
:
: my $infile = shift @ARGV;
: my $outfile = shift @ARGV;
:
: open( my $infile_handle, "< $infile" ) or
: die "\nCan't open input file \"$infile\".\n",
: "Error: $!.\n",
: "Stopped";
Don't see an immediate problem here, but you are using an older version of Perl. This means it may like you to declare $infile_handle before the open statement, e.g.:-

my $infile_handle;
open $infile_handle, "< $infile" or ...blah...;

: open( my $outfile_handle, "> $outfile" ) or
: die "\nCan't open output file \"$outfile\".\n",
: "Error: $!.\n",
: "Stopped";
And maybe the same there.

: my $text = join( '', <$infile_handle> );
: my $test_len = length( $test );
Should that not be:-
my $test_len = length( $text );

: print "\n" , $test_len, "\n";
:
: close $infile_handle;
:
: chomp $text;
:
: #
: # process the line and print results...
: #
:
: close $outfile_handle;
:
: exit ( 0 );

Looks OK besides that. FYI, it's good to enclose code in code and /code tags - tags are put in square brackets. Then the spacing is retained.

Hope this helps, if not please post the output of perl -c thescript.pl, where thescript.pl is your script. That or run it and post the warnings that you're given.

Jonathan

###
for(74,117,115,116){$::a.=chr};(($_.='qwertyui')&&
(tr/yuiqwert/her anot/))for($::b);for($::c){$_.=$^X;
/(p.{2}l)/;$_=$1}$::b=~/(..)$/;print("$::a$::b $::c hack$1.");

Re: New to Perl and stuck...Help

Thu, 18 Dec 2003 14:19:04 -0700

This message was edited by mikeruth at 2003-12-18 14:28:27

This message was edited by mikeruth at 2003-12-18 14:25:13

I made the changes that you suggested (thanks for catching the "test"
error). The new code is:

my $infile_handle;
open( $infile_handle, "< $infile" ) or ...

When run I get:

Can't use an undefined value as a symbol reference at edijd110.pl line 24. <--- the open above

With -c I get:

edijd110.pl syntax OK

: : open( my $infile_handle, "< $infile" ) or
: : die "\nCan't open input file \"$infile\".\n",
: : "Error: $!.\n",
: : "Stopped";
: Don't see an immediate problem here, but you are using an older version of Perl. This means it may like you to declare $infile_handle before the open statement, e.g.:-
:
: my $infile_handle;
: open $infile_handle, "< $infile" or ...blah...;
:
: : open( my $outfile_handle, "> $outfile" ) or
: : die "\nCan't open output file \"$outfile\".\n",
: : "Error: $!.\n",
: : "Stopped";
: And maybe the same there.
:
: Looks OK besides that. FYI, it's good to enclose code in code and /code tags - tags are put in square brackets. Then the spacing is retained.
:
: Hope this helps, if not please post the output of perl -c thescript.pl, where thescript.pl is your script. That or run it and post the warnings that you're given.
:
: Jonathan
:
: ###
: for(74,117,115,116){$::a.=chr};(($_.='qwertyui')&&
: (tr/yuiqwert/her anot/))for($::b);for($::c){$_.=$^X;
: /(p.{2}l)/;$_=$1}$::b=~/(..)$/;print("$::a$::b $::c hack$1.");
:
:

Re: New to Perl and stuck...A solution??

Thu, 18 Dec 2003 14:43:31 -0700

I found a solution but I do not know why it works.

I deleted the line "my $infile_handle;".
I changed all occurences of "$infile_handle" to "INFILE_HANDLE".

Why does this work?

: This message was edited by mikeruth at 2003-12-18 14:28:27

: This message was edited by mikeruth at 2003-12-18 14:25:13

: I made the changes that you suggested (thanks for catching the "test"
: error). The new code is:
:
: my $infile_handle;
: open( $infile_handle, "< $infile" ) or ...
:
: When run I get:
:
: Can't use an undefined value as a symbol reference at edijd110.pl line 24. <--- the open above
:
: With -c I get:
:
: edijd110.pl syntax OK
:
:
: : : open( my $infile_handle, "< $infile" ) or
: : : die "\nCan't open input file \"$infile\".\n",
: : : "Error: $!.\n",
: : : "Stopped";
: : Don't see an immediate problem here, but you are using an older version of Perl. This means it may like you to declare $infile_handle before the open statement, e.g.:-
: :
: : my $infile_handle;
: : open $infile_handle, "< $infile" or ...blah...;
: :
: : : open( my $outfile_handle, "> $outfile" ) or
: : : die "\nCan't open output file \"$outfile\".\n",
: : : "Error: $!.\n",
: : : "Stopped";
: : And maybe the same there.
: :
: : Looks OK besides that. FYI, it's good to enclose code in code and /code tags - tags are put in square brackets. Then the spacing is retained.
: :
: : Hope this helps, if not please post the output of perl -c thescript.pl, where thescript.pl is your script. That or run it and post the warnings that you're given.
: :
: : Jonathan
: :
: : ###
: : for(74,117,115,116){$::a.=chr};(($_.='qwertyui')&&
: : (tr/yuiqwert/her anot/))for($::b);for($::c){$_.=$^X;
: : /(p.{2}l)/;$_=$1}$::b=~/(..)$/;print("$::a$::b $::c hack$1.");
: :
: :
:
:
:
:
:
:

Re: New to Perl and stuck...A solution??

Thu, 18 Dec 2003 14:56:47 -0700

: I found a solution but I do not know why it works.
:
: I deleted the line "my $infile_handle;".
: I changed all occurences of "$infile_handle" to "INFILE_HANDLE".
That was going to be my suggestion, but I went to grab some whisky before replying and you beat me to it.

: Why does this work?
In older versions of Perl 5 it was not possible to store a file handle in a scalar. 5.005 qualifies as "older".

Jonathan

###
for(74,117,115,116){$::a.=chr};(($_.='qwertyui')&&
(tr/yuiqwert/her anot/))for($::b);for($::c){$_.=$^X;
/(p.{2}l)/;$_=$1}$::b=~/(..)$/;print("$::a$::b $::c hack$1.");

Re: New to Perl and stuck...A solution??

Thu, 18 Dec 2003 15:01:57 -0700

Thank you for your help and time.

: : I found a solution but I do not know why it works.
: :
: : I deleted the line "my $infile_handle;".
: : I changed all occurences of "$infile_handle" to "INFILE_HANDLE".
: That was going to be my suggestion, but I went to grab some whisky before replying and you beat me to it.
:
: : Why does this work?
: In older versions of Perl 5 it was not possible to store a file handle in a scalar. 5.005 qualifies as "older".
:
: Jonathan
:
:
: ###
: for(74,117,115,116){$::a.=chr};(($_.='qwertyui')&&
: (tr/yuiqwert/her anot/))for($::b);for($::c){$_.=$^X;
: /(p.{2}l)/;$_=$1}$::b=~/(..)$/;print("$::a$::b $::c hack$1.");
:
: