Shell Programming and Scripting

Hello All,

I have a perl script , and the STDERR and additional FH is redirected to the STDOUT like below:
open STDOUT ,">>$log" or die "$! :: $log\n";
open STDERR ,">&STDOUT" or die "$! :: Can redirect STDERR to STDOUT\n";
select STDERR; $|=1;
open LOG ,">&STDOUT" or die "$! :: Can redirect LOG FH to STDOUT\n";
select LOG ; $|=1;
select STDOUT; $|=1;

Everything work fine but when I close this three FH as shown below:
$|=0;
close STDERR;
close LOG;
close STDOUT;
print "Done\n"

I expect to see my print "Done" on the screen , but oddly I don't.

Are anyone know what am I doing wrong ?
Your help will appreciated !

Thanks.

i dont know about perl, but in bash if you redirect the stdout to something else, and then close it, you have to reopen it poiting to the "screen"

So, Perl inherits the streams pointed to by STDIN, STDOUT and STDERR from the shell. If you need to re-connect them to other streams the way you did, you should first save a reference to the original filehandles in some variables beforehand, so that when you need to restore you can reinitialize them using these references saved. Otherwise, the streams are closed and you have no way to open them again until the end of your script.

Or, you can wrap the code needed to use custom STD* streams in a code block, and use "local" variable instead. This way, the original streams are just suppressed but not closed while in the code block, that will be restored when the local scope terminates.

I'll give you an example of the second approach because I think this is easier.

Code:

print "This will be printed to STDOUT\n";
{
    local *STDOUT;
    open(STDOUT, ">/dev/null") or die $!;
    print "This will be trashed to nowhere\n";
}
print "This will be printed to STDOUT\n";