Perl，对散列中存储的用户使用linux命令

Question

Here is the code:

#!/usr/bin/perl

use warnings;
use strict;
use utf8;


my @temparray;
my $count = 0;
my @lastarray;
my $lastbash;


#Opens the file /etc/shadow and puts the users with an uid over 1000 but less that 65000 into an array.
open( my $passwd, "<", "/etc/passwd") or die "/etc/passwd failed to open.\n";

    while (my $lines = <$passwd>) {
        my @splitarray = split(/\:/, $lines );
        if( $splitarray[2] >= 1000 && $splitarray[2] < 65000) {

            $temparray[$count] =$splitarray[0];
            print "$temparray[$count]\n";
            $count++;
        }
    }
close $passwd;

foreach (@temparray) {
    $lastbash = qx(last $temparray);
    print "$lastbash\n";
}

What I want to do is use the built in linux command "last" on all the users stored in the @temparray. And i want the output to be like this:

user1:10

user2:22

Where 22 and 10 being the number of times they logged in. How can I achieve this ? I have tried several different ways but I always end up with errors.

Answer 1

The following should perform the task as requested:

#!/usr/bin/perl

use warnings;
use strict;
use utf8;


my @temparray;
my $count = 0;
my @lastarray;
my $lastbash;


#Opens the file /etc/shadow and puts the users with an uid over 1000 but less that 65000 into an array.
open( my $passwd, "<", "/etc/passwd") or die "/etc/passwd failed to open.\n";

    while (my $lines = <$passwd>) {
        my @splitarray = split(/\:/, $lines );
        if( $splitarray[2] >= 1000 && $splitarray[2] < 65000) {

            $temparray[$count] =$splitarray[0];
            print "$temparray[$count]\n";
            $count++;
        }
    }
close $passwd;

foreach (@temparray) {
    my @lastbash = qx(last $_); #<----Note the lines read in go to the $_ variable. Note use of my. You also read the text into array.
    print $_.":".@lastbash."\n";  #<----Note the formatting. Reading @lastbash returns the number of elements.
}

Answer 2

You don't really need the $count , you could just do push @temparray, $splitarray[0] .

That said, I'm not sure why you need @temparray either... You can just run the command against the users as you find them.

my $passwd = '/etc/passwd';
open( my $fh, '<', $passwd )
  or die "Could not open file '$passwd' : $!";

my %counts;

# Get `last` counts and store them %counts
while ( my $line = <$fh> ) {
    my ( $user, $uid ) = ( split( /:/, $line ) )[ 0, 2 ];
    if ( $uid >= 1000 && $uid < 65000 ) {
        my $last = () = qx{last $user};
        $counts{$user} = $last
    }
}
close $fh;

# Sort %counts keys by value (in descending order)
for my $user ( sort { $counts{$b} <=> $counts{$a} } keys %counts ) {
    printf "%s:\t %3d\n", $user, $counts{$user};
}