Sort lines by number of words per line

You could do something like:

awk '{print NF,$0}' file | sort -nr | cut -d' ' -f 2-

We use awk to prefix the number of fields to each line. We then sort by that number and remove it with cut.

In recent GNU awk one can use PROCINFO array to define many internal parameters including order in which array elements are printed (controlled by element "sorted_in"). Thus we can built and array indexed with the value of NF" "NR, which elements have value of $0 and print it in desired output, in your case that would be "@ind_num_desc":

awk '{a[NF" "NR]=$0}END{PROCINFO["sorted_in"]="@ind_num_desc"; for(i in a) print a[i]}' file

Perl one-liner:

print sort { split(' ',$a) <=> split(' ',$b) } <>;

If you want to break ties using alphabetical order:

print sort { split(' ',$a) <=> split(' ',$b) or $a cmp $b } <>;