[lvvlvv]

  # --- print second column 
  ls -al | awk '{print $2}'
  ls -al | pru 'split(" ")[1]'
  ls -al | scc -n 'F(1)'

  # --- count and average of all integers on second position
  ls -al | awk '{ s += $2; } END {print "average" ,int(s/NR);print "count ",int(NR)}'
  ls -al | pru 'split(" ")[1]' '"average #{mean(&:to_i)}\ncount #{size}"'
  ls -al | scc 'int c=0; WRL c+=F(1); FMT("average %s\ncount %s") %(c/NR) %NR'

  # --- count lines
  ls -al | wc -l  
  ls -al | pru -r 'size'
  ls -al | scc 'WRL;NR+1'

  # -- replace a 5 with five
  ls -al | sed 's/5/five/'
  ls -al | pru 'gsub(/5/,"five")'
  ls -al | scc -n 'RR(line,R("5"),"five")'

  # every second line
  ls -al | pru 'i % 2 == 0'
  ls -al | scc -n 'NR % 2 ? line : ""'

  # sum up df's used-space column
  df | awk '{n+=$3;};  END{print n}'
  df | pru  ?????
  df | scc 'int n=0; WRL n+=F(2); n'