How come every post in this forum is a request for help?
How about some fun?
What does the following command do?
nawk -F'[^A-Za-z_]+' '
{i=NF;for(;i;i--)if($i)w[tolower($i)]++}
END{
for(k in w){c=w[k];x[c]=x[c]k",";if(c>m)m=c}
for(;m;m--)if(m in x)print m,x[m]
}
' <(man nawk)