in reply to Help: STDOUT flaking out?

or try this.... 
#!/usr/bin/perl


  # just make up a fake file here to create
  # and echo the filename of /tmp/foo
  $tabfile = "./tabfile";
  $logfile = "/tmp/foo";

  # send output to file
  @args2 = ("$tabfile");
  {
  local(*STDOUT);
  open (STDOUT, ">$logfile") || die "could not open log\n";
  unless (system(@args2) == 0) {
         print STDERR "system(@args2) failed: $? $!\n";
         return;
  }
  close(STDOUT);
  }
  print "foo1\n";
}

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That should temporarily store STDOUT away and when you leave the code block, return its original value... I believe... not tested

Update you could also use select, open log filehandle OUT say, instead of STDOUT, then do select OUT; all output will go to OUT instead of STDOUT until you do select STDOUT; to put it back...
                - Ant

Replies are listed 'Best First'.
Re: Re: Help: STDOUT flaking out?
by P0w3rK!d (Pilgrim) on May 17, 2001 at 19:23 UTC
    This still is not working. The file "tabfile" is a shell script that created the file "FTPData.20010517.111754". I am trying to capture that echoed output and redirect it into a file. Might there be a better way to do this with a pipe or some other mechanism? Please advise :) 
    RESULT:
$ ftp_flow.pl
logfile = /tmp/ftp_flow.111753410117.log
errfile = /tmp/ftp_flow.111753410117.err
FTPData.20010517.111754
$ cat /tmp/ftp_flow.111753410117.log
$

(the file is empty... it should contain 
"FTPData.20010517.111754" as the 1st line)

CODE:
# send output to file
@args2 = ("$tabfile");
local(*LOGFILE);
open (LOGFILE, ">$logfile") || die "could not open log\n";
select(LOGFILE);
unless (system(@args2) == 0) {
        print STDERR "system(@args2) failed: $? $!\n";
        return;
}
close(LOGFILE);

print "foo1\n";
exit (0);

    [download]
[reply]
[d/l]
      you probably really want to just use backticks... 
      # send output to file
###either
  open (LOGFILE, ">$logfile") || die "could not open log\n";
  print LOGFILE `$tabfile`;  
  if($?) {
        print STDERR "$tabfile failed: $?\n";
        return;
  }
  close(LOGFILE);
##or
  `$tabfile > $logfile`;
  if($?) {
        print STDERR "$tabfile failed: $?\n";
        return;
  }
## end or

  print "foo1\n";
  exit (0);

      [download]

                      - Ant
[reply]
[d/l]
        Thank you. I removed the code which was screwing up STDOUT. It all works now. :)
[reply]

      You need to select(STDOUT); after your close(LOGFILE);. Right now, you're still printing to a closed filehandle...

[reply]
[d/l]
[select]
      This works now: Thank you :) 
      # send output to file
@args2 = ("$tabfile");
open (LOGFILE, ">$logfile") || die "could not open log\n";
unless (system(@args2) == 0) {
        print STDERR "system(@args2) failed: $? $!\n";
        return;
}
select(LOGFILE);
close(LOGFILE);

      [download]
[reply]
[d/l]
        In reference to the previous postings: After I cat the log file I create, it shows that not only the 1st line which was grabbed from the $tabfile output, but also the output from: 
        print "foo1\n";

        [download]
        and 
         
print "GOT THIS: $lines\n";

        [download]
        RESULT:

$ ftp_flow.pl
logfile = /tmp/ftp_flow.12547410117.log
errfile = /tmp/ftp_flow.12547410117.err
$ cat /tmp/ftp_flow.12547410117.log
FTPData.20010517.120547
foo1
GOT THIS: FTPData.20010517.120547

$

        [download]
        How do I set STDOUT back to normal? 
        # send output to file
@args2 = ("$tabfile");
open (STDOUT, ">$logfile") || die "could not open log\n";
unless (system(@args2) == 0) {
        print STDERR "system(@args2) failed: $? $!\n";
        return;
}
select(STDOUT);
close(STDOUT);

print "foo1\n";

# read the file to obtain the file tabdata created
local(*LOGFILE);
open (LOGFILE, $logfile) || die "Couldn't open: $!";
$lines=<LOGFILE>; #get line 1 from the file
close(LOGFILE);
print "GOT THIS: $lines\n";
exit(0);

        [download]
[reply]
[d/l]
[select]

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