Question

I am trying to redirect perl system command to output file with the following code along with time but its not working ??

$cmd="echo hi";
($second, $minute, $hour) = localtime();
$time="$hour:$minute:$second";

system("$time>new.txt");

system("$cmd   1>>new.txt 2>>&1");

Answer 1

If you want to write the variable $time to a text file, open a writeable filehandle and print it to your file instead.

open(my $outfile, '>', 'new.txt');
print $outfile $time;
...

Secondly, your output redirection should read:

1>>new.txt 2>&1

Which means “append STDOUT (1) to new.txt, redirect STDERR (2) to STDOUT (1)”. Having >> makes no sense for the second part.

Finally, I (and every other perl programmer) would strongly recommend using strict and warnings pragmas in your scripts. This will help you pick up on any errors or potential problems in your scripting. Once you’ve done this, all variables must be declared with my, which is a good habit to get in to anyway. So after all that, your script should look something like this:

# recommended pragmas:
use strict;
use warnings;

# declare all new variables with "my"
my $cmd="echo hi";
my ($second, $minute, $hour) = localtime();
my $time="$hour:$minute:$second";

# open a writeable filehandle and print to the filehandle
open(my $outfile, '>', 'new.txt');
print $outfile $time,"\n"; # I've added a newline character here so that 
                           # the time and the command's output are on different lines ;)

system("$cmd   1>>new.txt 2>&1");