[root@os-lab pebsim]# history | awk {'print $2'} | sort | uniq -c | sort -k1 -rn | head

   379 ./simics
    256 make
    157 ls
     81 cd
     33 vim
     12 quit
     11 tar
      6 rm
      6 man
      5 exit

感觉挺可怕的..