Receiving strange error when piping yes into rm -r command - perl

Question

I receive the following
yes: standard output: broken pipe
yes: write error
when executing the following line in perl
system("cd /tmp; yes | rm -r directory1 directory2 file3 > /dev/null 2>&1");
The files and directories still get deleted but the message is annoying and would prefer not to see it.
any help Thanks

Answer 1

Not really a Perl question.
The error comes from yes, so you would have to redirect the error stream of yes, too.
... ; yes 2>/dev/null | rm -r ...
But why don't you forget about yes and try rm -rf ... ?

Answer 2

You say Perl, but your question says Unix shell.
If you're going to use Perl, do it in Perl:
use File::Path qw(remove_tree);
use Cwd;
my $current_directory = getcwd();
chdir "tmp";
remove_tree("directory1", "directory2, "file3");
chdir $current_directory;
This will do the same thing as your system command. But, this will work not only on Unix systems, but also on strange and peculiar operating systems that no man should be subject to (Cough, Windows! Cough).
It also will work even if someone has created an alias rm command, or has implemented their own rm command. Whenever you shell out via the system command, you leave that nice safe Perl environment and head directly into the dangerous neighborhood of the Operating System. Even worse, you're placing your life into the hands of a shell that might not be the shell you use either.
The module File::Path is a standard module that comes with Perl. Same goes with Cwd I used to save your original directory, so we could come back to it at the end of your code.
By the way, you probably want some error checking there too:
use File::Path qw(remove_tree);
use Cwd;
my $current_directory = getcwd();
if chdir "tmp" {
remove_tree("directory1", "directory2, "file3");
chdir $current_directory;
}
else {
print "Whoops! I can't change to directory 'tmp'"
}
This way, you are only doing the remove_tree if you've actually changed into directory tmp.
If this is your temporary working directory. That is, you've created it, so you have a place to put files, , you might should look at the File::Temp module.
File::Temp (which is also a standard Perl module) can create the temporary directory for you, and makes sure that it's unique, so you're not trampling over someone else running your program at the same time. Even better, it will also clean up after itself and delete that temporary directory once complete.
use File::Temp;
my $temp_dir = File::Temp->newdir;
Now, you can put all of your temporary files into $temp_dir. When the program ends, the temporary directory and all files you placed there are automatically deleted.
Although not part of the standard Perl functions, these modules are part of Perl's distribution and are always available. There should be no reason at all not to use them. If you're using the system command, there is probably a standard Perl module that you should be using instead.
Browse through the list of Perl modules in the Perdoc Webpage. Just make sure you select the version of Perl you're using.

Answer 3

To prevent questions, use -f or --interactive=never if implemented. See man rm.