Re: Syntax query

On Wed, Apr 15, 2009 at 10:41, John W. Krahn <jwkrahn@xxxxxxx> wrote:
Chas. Owens wrote:

On Wed, Apr 15, 2009 at 09:20, Rajini Naidu <rajinidots@xxxxxxxxx> wrote:

 I am trying to execute the below line in the perl program and returns a
value 0.

my $test2 = "";
my $include =  "file";

$test2 = system("/usr/atria/bin/cleartool desc \$include | grep created |
awk -F\" \" \'{print \$2}\' | cut -b 1-9 ");

The value returned by $test2 is 0. I suspect grep and awk commands are
not
getting executed.
Is there any thing wrong in the syntax ????

The system[1] function returns 0 on success and a nonzero value
specific to the operating system on failure (often the programs
exit code and the value returned by exec[2]).  You could use the
qx// operator[3] to capture the STDOUT of the command:

my $test2 = qx{/usr/atria/bin/cleartool desc \$include |
   grep created | awk -F\" \" \'{print \$2}\' | cut -b 1-9};

but a much safer and faster way is to use the open[4] function
and avoid using external programs like grep and awk:

open my $pipe, "-|", "/usr/atria/bin/cleartool", "desc", $include
   or die "could not run cleartool: $!";

my @matches;
while (<$pipe>) {
   next unless /created/;
   my @rec = split;
   push @matches, substr $rec[1], 0, 9;
}

Don't forget to verify that the pipe also closed correctly:

close OUTPUT or warn $! ? "Error closing /usr/atria/bin/cleartool pipe: $!"
                       : "Exit status $? from /usr/atria/bin/cleartool";
snip

If that is going to match the example it should be

close $pipe
or warn $! ? "Error closing /usr/atria/bin/cleartool pipe: $!"
: "Exit status $? from /usr/atria/bin/cleartool";


--
Chas. Owens
wonkden.net
The most important skill a programmer can have is the ability to read.
.

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