Shell Programming and Scripting

ps aux --sort -%cpu | uniq

ps aux --sort %cpu |
  perl -nle'/\s+\d?:\d+\s+(.+?)$/;print unless $_{$1}++
  '

USER   PID   %CPU %MEM   VSZ   RSS TTY   STAT START TIME COMMAND
root  28755  0.0  0.0  49588  3052 ?     Ss   11:32   0:00     login -- petros
root  30041  0.0  0.0 49588 3176 ?        Ss   11:44   0:00 login -- petros
root  30042  0.0  0.0 49588 3176 ?        Ss   11:44   0:20 login -- pet

USER    PID      TIME  COMMAND
root    28755    0:00  login--petros
root    30042    0:20 login --pet

ps aux | perl -nle'
    print and next if $. == 1;
    if (/^\w+\s+(\d+)\s+.*?[\d:]+\s+(\d+):(\d+)\s+(.*)?$/) {
        $_{$4} = [ $1, $2, $3, $_ ];
        $_{4}->[0] > $1 and $_{$4}->[0] = $1;
    }
    print join $/, map $_{$_}->[3],
      sort { $_{$a}->[1] <=> $_{$b}->[1] || $_{$a}->[2] <=> $_{$b}->[2] }
      keys %_
      if eof'

ps aux | perl -nle'
    print and next if $. == 1;
    if (/^\w+\s+(\d+)\s+.*?[\d:]+\s+(\d+):(\d+)\s+(.*)?$/) {
      next if exists $_{$4}->[0] and $_{$4}->[0] < $1;
      $_{$4} = [ $1, $2, $3, $_ ];
      }    
    print join $/, map $_{$_}->[3],
      sort { $_{$a}->[1] <=> $_{$b}->[1] || $_{$a}->[2] <=> $_{$b}->[2] }
      keys %_
      if eof'