[johan@laptop ~]$ history|awk '{a[$2]++ } END{for(i in a){print a[i] " " i}}'|sort -nr|head
201 ls
108 ssh
108 cd
98 sh
81 su
29 vi
24 rpm
24 ping
23 rm
20 mv

[johan@workstation ~]$ history|awk '{a[$2]++ } END{for(i in a){print a[i] " " i}}'|sort -nr|head
149 ls
128 cd
125 cvs
93 diff
71 echo
54 ssh
45 for
28 mkdir
26 md5sum
24 reset

My previous post of my Top 10 used commands was more than 1 year ago.