On Windows:

C:\Windows\system32>pwd
/c/Windows/system32

C:\Windows\system32>perl -E"say `pwd`"
/c/Windows/system32


C:\Windows\system32>perl -E"say eval{`pwd`}"
/c/Windows/system32


C:\Windows\system32>perl -E"say eval{'pwd'}"
pwd

C:\Windows\system32>perl -E"say system('pwd')"
/c/Windows/system32
0
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On Linux (Raspbian):

dr@mail:~ $ pwd
/home/dr
dr@mail:~ $ perl -E'say `pwd`'
/home/dr

dr@mail:~ $ perl -E'say eval{`pwd`}'
/home/dr

dr@mail:~ $ perl -E'say eval{"pwd"}'
pwd
dr@mail:~ $ perl -E'say system("pwd")'
/home/dr
0
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I think you are confusing yourself by combining eval with backticks. Backticks alone should work, as demonstrated above. I prefer qx() to backticks as I find it clearer, but the effect is identical and a matter of preference. Your error message suggests that the executable is either not where you expect or not named what you think, but that's a different problem. Try the examples I have given with your executable and you should end up on the right road.

Regards,

John Davies

Almost immediate update as you solved your problem while I was composing my suggestions: it looks as though the executable was not where you expected. The leading two dots are taking you to a relative directory rather than the absolute one you specified originally.

G'day Takamoto,

[I created a quick test.pdf, with just the text "Test for PM 11148715", for the tests below. I don't have p2t, but I do have pdftotext, which appears to have the same functionality and accepts the same options.]

You appear to have got bogged down in absolute vs. relative paths and eval code.

If your p2t is in a directory listed in $PATH, you don't technically need a path at all; however, using an absolute path avoids tainting.

If all you want to do is print the PDF text, you can use system() or backticks like one of these:

$ perl -e 'system "pdftotext -nodiag -layout -enc UTF-8 test.pdf -"'
Test for PM 11148715

$ perl -e 'print `pdftotext -nodiag -layout -enc UTF-8 test.pdf -`'
Test for PM 11148715
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If you want something a little more robust, that avoids the overhead of using the shell, consider capturex() from IPC::System::Simple. Here's an example (p2t_capturex.pl):

#!/usr/bin/env perl

use strict;
use warnings;

use IPC::System::Simple 'capturex';

my $p2t_exe = 'C:/cygwin64/bin/pdftotext.exe';
my $pdf_doc = 'test.pdf';

print capturex(
    $p2t_exe => qw{-nodiag -layout -enc UTF-8}, $pdf_doc, '-'
);
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You get the same output as before:

$ ./p2t_capturex.pl
Test for PM 11148715
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$ ls -i1 `which pdftotext` C:/cygwin64/bin/pdftotext.exe
844424931368301 /usr/bin/pdftotext
844424931368301 C:/cygwin64/bin/pdftotext.exe
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If you want something a little more robust, that avoids the overhead of using the shell, consider capturex() from IPC::System::Simple.

It is indeed much more robust and a good suggestion! Just a small nitpick: on Windows it is almost impossible to avoid the shell*. IPC::System::Simple works around this by using Win32::ShellQuote under the hood.

* Update: See my clarification further down in the thread.

G'day haukex,

"Just a small nitpick: on Windows it is almost impossible to avoid the shell."

I checked out that module's documentation and code not so long; I've just checked again. Both are still very clear that capturex() does not invoke the shell. Here's a selection of extracts (non-exhaustive):

From SYNOPSIS:

# As above, but NEVER invokes the shell.
my $output = capturex("some_command", @args);
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From source, starting at Line 361 (note the "NO_SHELL"):

# capturex() is just like backticks/qx, but never invokes the shell.
 
sub capturex {
...
        if (WINDOWS) {
            return _win32_capture(NO_SHELL, $valid_returns, $command, 
+@args);
        }
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Are you possibly confusing capturex() with capture()? Same source, starting at Line 220 (note the "USE_SHELL"):

# capture is our way of running a process with backticks/qx semantics
 
sub capture {
...
        if (WINDOWS) {
            # USE_SHELL really means "You may use the shell if you nee
+d it."
            return _win32_capture(USE_SHELL, $valid_returns, $command)
+;
        }
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If not a case of confusion, do you think the documentation, code, or something else, is wrong?

All links and extracts are from the IPC-System-Simple-1.30 distribution (released "Mar 24, 2020").

— Ken

solved.

eval { $converted_text   = `../Desktop/p2t -nodiag -layout -enc UTF-8 
+$PathDocumentUnicode -` }
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Why I have to add '..' is not clear to me. But it does the trick.

You putting two dots before the path turns the path into a relative path whereas having / as the first character makes it an absolute path. In Windows, the Desktop folder is usually found within the user's folder which is located under C:\Users

C:\Users\username\Desktop is a valid path but C:\Desktop is not likely unless you have created such a directory.

Also: It is not common practice in Windows to store exe files in the Desktop directory! The Desktop directory usually has Word documents, pictures, txt files and lnk files.