vmstat reports information about processes, memory, paging, block IO, traps, disks and cpu activity.

the output is like this

procs ------memory------- --swap-- ---io--- -system-- ----cpu----
 r b swpd free buff cache  si  so   bi   bo  in    cs   us sy id  wa
 0 0  0   9999 9999 9999    0   0   99   99  9999  999  9  9  99  9
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Let's see...

Your target is the 13th number in the third line, so you need to discard lines 1 and 2, and then print this element

my @stat = `vmstat`;
foreach $line(@stat){
    if ($line =~ /^procs/){next}
    if ($line =~ /us/){next}
    else {chomp $line;
          my @fo = split /[[:blank:]]+/, $line;
          print "Message: CPU user time: $fo[13]\n";}
}
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