rkshyam has asked for the wisdom of the Perl Monks concerning the following question: 

Hi,
This is my small portion of a bigger program.
I need to concatenate 3 variables.The details are here.But output is r
+esulting in 2 seperate lines rather than on a single line

or in an another way I need to add \dir2 to the main directory path C:
+\shyam\dir1 and final path should be

 "C:\shyam\dir1\dir2" when printed or accessed in program but i am get
+ting as C:shyam\dir1 and \dir2 in 2 seperate lines.Because of this my
+ copy is failing. 

Please help

[download]

$\ = "\n" ; 
$, = "\t" ;
#$|=1;
use strict;
use warnings;
use POSIX qw[ _exit ];
use MIME::Lite;
use Sort::External;
use Net::Ping;
use Win32::DriveInfo;


$source="C:\shyam\dir1;

$sym="\";

$file="dir2"; ## please note that this value is not directly assigned 
+but being extracted from another directory path using slicing.Ex: C:\
+sundar\dir2

$source_mod=join '',$source,$sym,$file;

print "$source_mod";

Note: I have also used . opeartor but result is still the same.I am su
+specting about $\="\n" in the beginning.But this is required as the o
+ther part of my program needs this.

Please help

[download]

Replies are listed 'Best First'.
Re: concatenation of variables resulting in 2 seperate lines
by Corion (Patriarch) on Jul 25, 2012 at 10:32 UTC

    What are these lines supposed to do:

    $source="C:\shyam\dir1;

$sym="\";

    [download]

    These do not look like they are syntactically correct. Please reduce your program to a short, runnable program that still reproduces the problem.

    Also note that backslashes in double quotes likely do not mean what you think they do. Double quotes interpret backslashes.

[reply]
[d/l]
      those 2 are two variables needed for concatenation

final my $source_mod should contain "C:\shyam\dir1\dir2"
that is the $source is concatenated with two variables \ and dir2.I am
+ not sure how backslash can be used to concatenate as a variable

      [download]
[reply]
[d/l]

        There is at least one quote missing in this line:

        $source="C:\shyam\dir1;

        [download]

        Again, please fix your program, or post the real program and not some vague interpretation.

[reply]
[d/l]
Re: concatenation of variables resulting in 2 seperate lines
by BillKSmith (Monsignor) on Jul 25, 2012 at 13:21 UTC
    I am suspecting about $\="\n" in the beginning. But this is required as the other part of my program needs this.

    To prevent this problelm, perl special variables (such as $\) should be declared with local in the smallest possible block where they are needed. Refer perldoc -f local

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[d/l]
Re: concatenation of variables resulting in 2 seperate lines
by tfredett (Sexton) on Jul 25, 2012 at 13:51 UTC

    Overall good question, although its not a huge deal, please do read How do I post a question effectively?. It will help us here, read your question a little easier, and thus answer it faster, and who doesn't love speed? :)

[reply]
      Here is the detailed Problem statement and my approach:

config.txt contains 2 section DIR and FILE.
DIR has list of directory path and FILE section has file path
I need to read the file line by line and check if each line is a file 
+or a directory.
It is required to copy the entire directory content to source director
+y.
Similarly mentioned file needs to be copied to source directory
I need to use robocopy to copy large files.The program is working for 
+copying file but not for copying directory.
For this i thought to split the last part of directory path and attach
+ this to source path inorder to copy using robocopy.

the syntax of robocpy command is

robocopy  $target_file $source_dir_mod ## here target_file=C:\shyam\di
+r1 and i need to get source_dir_mod=C:\sundar\directory1\dir1
Then I can copy dir1 to the source directory

[DIR]
C:\shyam\dir1

[FILE]
C:\shyam\output.txt

$\ = "\n" ; 
$, = "\t" ;
#$|=1;
use strict;
use warnings;
use POSIX qw[ _exit ];
use MIME::Lite;
use Sort::External;
use Net::Ping;
use Win32::DriveInfo;





my $source_dir = `pwd`;#C:\sundar\directory
my $source_dir_mod;



my $file_config = "config.txt";
my $sym = '\\' ;
    open FH_config, "$file_config" or die "$!";
        

        while (my $line = <FH_config>)
        {
            chomp $line;
            next if $line eq "";
            if (($line eq "[DIR]") or ($line eq "[FILE]"))
            {
            #print "no action";
            }
            else 
            {
            my $target_file = $line;
            #print $target_file;
                if (-d $target_file)
                {
                    print("it is directory");
                    
                    (my $path,my $file) = $target_file =~ m|^(.*[/\\])
+([^/\\]+?)$|;
                    
                    $source_dir_mod = join '',$source_dir,$sym,$file;
                    print ($source_dir_mod);
                    `robocopy  $target_file $source_dir_mod`;
                    #print "$path"; ##C:\shyam
                    #print "$file"; ##dir1
                }
                elsif(-f $target_file)
                    {
                    print("is a file");
                    
                    
                    (my $path,my $file) = $target_file =~ m|^(.*[/\\])
+([^/\\]+?)$|;
                    #print "$path"; ##C:\shyam
                    #print "$file"; ##output.txt
                    `robocopy \/Z $path $source_dir $file`;
                    }
                else
                {
                print("no action");
                }
                
            }
        }

        
    close FH_config;

      [download]
[reply]
[d/l]

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