On 17.4.2014 8:47, John Emmas wrote:
Firstly, please forgive me if this isn't the right place for asking this
question. I tried a couple of programmer's forums but up to now, my
question hasn't even gained one answer! And yet it seems like a simple
(and probably very common) requirement. I'm hoping that someone here
will take pity on me!
I've been using Strawberry perl for about 6 months and I'm generally
happy with it. The one thing I just can't seem to make it do is to run
an external program and capture that program's output to a file. I came
across perl's 'system' command. Let's say I add these lines to a perl
script:-
@my_command = ( "the_exe_name", "arg1", "arg2", "etc" );
system(@my_command);
If I now open a DOS window and run the perl script, sure enough, it runs
'the_exe_name'. And if my exe produces any text output I can see that
output in my DOS window.. Suppose my perl script is called
"my_perl_script.pl". If I try to redirect its text output (like this)
something interesting happens:-
my_perl_script.pl > output.txt
The above seems to work in Windows 7. However, it doesn't work in
Windows 8 or Windows XP. In both cases, the file "output.txt" does get
created. And in both cases I no longer see the exe's output text in my
DOS window (i.e. as if it's getting redirected to the file). But at the
end of the process (in both cases) output.txt will be an empty file. :-(
My next thought was to handle any redirection within the actual perl
script - i.e.
@my_command = ( "the_exe_name", "arg1", "arg2", "etc" ">",
"output.txt" );
system(@my_command);
Unfortunately, that doesn't seem to work either (again, it always creates
an empty file).
Is there a way to achieve this using Strawberry perl? Or am I making
some rookie mistake here? Admittedly I'm not very experienced with perl
but I'm amazed that such a simple task seems to defeat it :-(
Try:
my $output = `the_exe_name arg1 arg2`;
Or have a look at https://metacpan.org/pod/IPC::Run3
use IPC::Run3;
my $output;
run3(["the_exe_name", "arg1", "arg2", "etc"], undef, \$output);
--
kmx
