in reply to quoting/escaping file names

The shell's most likely your problem here, not Perl. Perl won't look at the contents of $filename if you interpolate it into a string, but the resulting string will be seen by a shell which will happily interpret $var if you're not careful.

The following works for me: 

#!/usr/bin/perl

use strict;
use warnings;

my $filename = q{$vaa it's not.txt};
$file =~ s/\$/\\\$/;

my $exec = `touch "$filename"`;

[download]

The double quotes (in the `` string) are passed to the shell there, and ensure that the spaces in $filename won't be an issue. The regular expression adds a backslash in front of the dollar sign; this keeps it from being interpreted by the shell. Finally, the single quote in the filename is not considered special by either Perl or the shell.

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Re^2: quoting/escaping file names
by Anonymous Monk on Sep 08, 2014 at 21:35 UTC

    It sounds like "$vaa it's not.txt" was only one example of a problematic filename, and so I gotta say I don't think your solution is general enough.

    Instead, I can only recommend to avoid the shell entirely (and only using the shell when you really know you really want its features - it really is another layer between Perl and the program you want to call, and you have to know how to use the shell, which isn't a given). This is possible via system (if you read its and the exec docs entirely because the invocation is a little tricky; and the output can be captured by something like Capture::Tiny), IPC::System::Simple, IPC::Run3, and a few others.

[reply]
[d/l]
Re^2: quoting/escaping file names
by famatte (Novice) on Sep 09, 2014 at 01:06 UTC
    Hello
    Here's a pratical example
    while(<>) {
        my $filename = q{$_};
        $filename =~ s/\$/\\\$/;
        my $exec = `md5sum "$filename"`;
        print $exec ."\n";
}

    [download]

    My input 
    /mnt1/$Recycle.Bin/S-1-5-21-3093161954-3233498542-1968413288-3198/$I7Q
+M78L.pdf<br>
/mnt1/$Recycle.Bin/S-1-5-21-3093161954-3233498542-1968413288-3198/$ID8
+4PBU.pdf<br>
/mnt1/$Recycle.Bin/S-1-5-21-3093161954-3233498542-1968413288-3198/$IDL
+L4FU.JPG<br>
/mnt1/$Recycle.Bin/S-1-5-21-3093161954-3233498542-1968413288-3198/$IE2
+ZPET.xls<br>
/mnt1/$Recycle.Bin/S-1-5-21-3093161954-3233498542-1968413288-3198/$IF7
+3ZR5.jpg<br>

    [download]

     find /mnt1/\$Recycle.Bin/ -type f | hash.pl The result ..
    md5sum: $_: No such file or directory <br>
md5sum: $_: No such file or directory <br>
md5sum: $_: No such file or directory <br>
md5sum: $_: No such file or directory <br>

    [download]

    But As I said before. file names could have spaces and quotes..

    ps: I know there's a DIGEST::MD5. Its only an example
[reply]
[d/l]
[select]

      Try removing this line: 

              my $filename = q{$_};

      [download]

      q// (or q{} etc.) is just the single-quote operator; I used that instead of the more customary single quotes to avoid having to escape the single quote in the string itself (which I felt would only serve to complicate the issue).

      See Quote and Quote like Operators and Quote Like Operators in perlop. Since this IS a single-quote, BTW, q{$_} (which is exactly the same as '$_') does not interpolate $_ into the string, and you end up passing a literal $_ to md5sum. And of course, it's unlikely that a file with that name exists.

      Long story short, just remove that line, it was just there to provide an example filename to work with.

[reply]
[d/l]
      Why did you type  my $filename = q{$_}; what do you think that does?
[reply]
[d/l]

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