System calls question

[tweetiebirds]

When calling system I would like the standard output to be printed to
standard out.

This is not happening - how do I make it happen:


system ("cp a b");


T

 

[Damian James]

When calling system I would like the standard output to be printed to
standard out.
This is not happening - how do I make it happen:
system ("cp a b");

print `cp a b`;

perldoc -q "Why can't I get the output of a command with system()?"
perldoc -f system

and see the section on qx// in perldoc perlop

Or if you need to take more control over the other process, see
the pipe version of open (ie, where MODE is '-|')

perldoc -f open


Cheers,
Damian

 

[jesper]

When calling system I would like the standard output to be printed to
standard out.

This is not happening - how do I make it happen:


system ("cp a b");


T

Well try

$result = `cp a b`;
printf $result;

does only print after execution though.

 

[Tad McClellan]

When calling system I would like the standard output to be printed to
standard out.

Good, as that is the default behavior.

This is not happening

Then there is a bug in your perl installation.

system ("cp a b");

What output are you expecting from cp(1)?

 

[Mark Clements]

print `cp a b`;

perldoc -q "Why can't I get the output of a command with system()?"
perldoc -f system

and see the section on qx// in perldoc perlop

Or if you need to take more control over the other process, see
the pipe version of open (ie, where MODE is '-|')

perldoc -f open

That being said, you won't get any output on stdout with the above
command, though you may get some on stderr.

Mark

 

[Damian James]

That being said, you won't get any output on stdout with the above
command, though you may get some on stderr.

Indeed. And system() does indeed send the other program's STDOUT to STDOUT,
so my suggestion above was pointless. Two things I just didn't spot, not
really my day

--damian

 

[Joe Smith]

$result = `cp a b`;
printf $result;

Best to break the C habits.
Don't use printf without a format.
Use a plain print instead.

 

[Joe Smith]

When calling system I would like the standard output to be printed to
standard out.

system ("cp a b");

Change that to either
system("cp -v a b");
or
system("cat a b");
depending on what you're really trying to accomplish.
-Joe

 

[Anno Siegel]

Well try

$result = `cp a b`;
printf $result;

Nonsense. That doesn't change the printing of stdout one whit.

Anno