On my macbook:

   1	90  18%    cd
     2	86  17.2%  rails
     3	64  12.8%  ls
     4	44  8.8%   ssh
     5	37  7.4%   rake
     6	34  6.8%   ping
     7	24  4.8%   git
     8	21  4.2%   dig
     9	11  2.2%   cat
    10	9   1.8%   whois