Question

I am running unix commands in perl as

$cmd="ls -l";
$result=`$cmd`;
print $log_file $result;

but the output from execution is also printed on screen.
how to execute command without printing result on screen ?

Answer 1

The standard output stream isn’t printed to screen — it’s captured to $result. But there is a second output stream called the standard error stream that programs can write to, and which also by default goes to the screen. Many programs use this stream for logging, or (in the case of ls) for writing error messages. To capture this in addition, use

$cmd = "ls -l 2>&1";

To discard it instead, use

$cmd = "ls -l 2>/dev/null";