A simple code runs at cmdline, but not in cron job

[whn]

A simple code just like this:

my $cmd = "gwsh root\@$ip \"uname -r\"";
my $ret = `$cmd`;

When I ran the code at cmd prompt, it's fine.

But when it's run in a cron job, $cmd returns nothing.

What did I miss here?

Many thanks.

 

[whn]

In addition, while the code is executed at cmd prompt, following three variables are the same as my own login ID:
$ENV{ LOGNAME }, getpwuid( $< ), & $ENV{ USER }.

However, while it's executed by the cron job, then $ENV{ USER } is undefined. But both $ENV{ LOGNAME } and getpwuid( $< ) are still the same as my own login ID.

Thanks.

 

[whn]

I got the solution. I need to set up two ENVs to make cron job run. Basically calling setEnv() before invoke gwsh. My sample code is listed below:

sub setEnv {
	my $sshPid = getSshPid(user=>$ENV{LOGNAME}, psName=>'ssh-agent');
	my $sshAuthSock = getSshAuthSock(sshPid=>$sshPid);

	my %newEnvs = (
		'SSH_AGENT_PID', $sshPid,
		'SSH_AUTH_SOCK', $sshAuthSock,
	);

	foreach my $k (keys(%newEnvs)) {
		if(!exists($ENV{$k}) || !$ENV{$k}) {
			$ENV{$k} = $newEnvs{$k};
		}
	}
}

sub getSshAuthSock {
	my %args = (@_);

	my $FPID = $args{sshPid} - 1;

	my $cmd = "find /tmp -path \"*ssh*\" -type s -iname \"agent.$FPID\"";
	my $sshAuthSock = `$cmd`;
	chomp($sshAuthSock);

	return $sshAuthSock;
}

sub getSshPid {
	my %args = (@_);

	my $cmd = "ps -ef | grep $args{user} | grep $args{psName} | grep -v grep";
	my $ret = `$cmd`;
	my $pid = (split(/\s+/, $ret))[1];

	return $pid;
}

Question:
I used shell cmd in my perl code. Could someone show me how to implement this in PURE perl code?

Thanks.