CODEWITHSUNDEEP
linuxperl
Majestic Pixel
Majestic Pixel

Reputation: 35

Perl - How to split input into an array?

I have a small Perl script that is used to take user command line input, and then splitting the input into an array where each service should be its own element.

My goal is to enable single arguments, as well as several arguments using a split character where every argument is separated by a comma sign. Examples of these would be:

My code looks as follows, it does compile without errors but the output is not the intended.

    print "Please provide the service name that you wish to analyze (Named service):\n";
    print "Several services may be provided, using a comma sign as a separator.\n";

    my $service_name_input = <>;
    chomp($service_name_input);
    my @service_list = split(/,/, $service_name_input);

    foreach my $line (@service_list)
    {
        open(my $service_input, "service @service_list status|");
    }

    foreach my $line (@service_list)
    {
        #Matches for "running".
        if ($line =~ m/(\(running\))/)
        {
            print "The service @service_list is running\n";
        }
        #Matches for "dead".
        elsif ($line =~ m/(dead)/)
        {
            print "The service @service_list is dead\n";
        }
    }

The program should output if the service is running or dead, but I only get the following error code. When manually issuing the service command, it works just fine though.

The service command supports only basic LSB actions (start, stop, restart, try-restart, reload, force-reload, status). For other actions, please try to use systemctl.

Any help regarding the steps I should take in order to achieve a working program will be much appreciated. Thank you for reading.

Upvotes: 0

Views: 285

Answers (1)

melpomene
melpomene

Reputation: 85837

foreach my $line (@service_list)
{
    open(my $service_input, "service @service_list status|");
}

This loop doesn't use $line. You're passing the whole array @service_list to the service command, i.e. you're running service ssh named cups status. This causes an error because service thinks you want to execute the named action on the ssh service. To fix that, write "service $line status |".

But there's another issue: You never do anything with $service_input either. If you want to loop over each line of each service command output, you need something more like:

foreach my $service (@service_list)
{
    open(my $service_input, '-|', 'service', $service, 'status')
        or die "$0: can't run 'service': $!\n";

    while (my $line = readline $service_input)
    {
        #Matches for "running".
        if ($line =~ m/(\(running\))/)
        {
            print "The service $service is running\n";
        }
        #Matches for "dead".
        elsif ($line =~ m/(dead)/)
        {
            print "The service $service is dead\n";
        }
    }
}

I've changed your open line to use a separate mode argument -| (which is good style in general) and the list form of process open, which avoids the shell, which is also good in general (no issues with "special characters" in $service, for example).

Upvotes: 2

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