Bash: sort text file by last field value

Question

I have a text file containing ~300k rows. Each row has a varying number of comma-delimited fields, the last of which is guaranteed numerical. I want to sort the file by this

Answer 1

Maybe reverse the fields of each line in the file before sorting? Something like

perl -ne 'chomp; print(join(",",reverse(split(","))),"\n")' |
  sort -t, -n -k1 |
  perl -ne 'chomp; print(join(",",reverse(split(","))),"\n")'

should do it, as long as commas are never quoted in any way. If this is a full-fledged CSV file (in which commas can be quoted with backslash or space) then you need a real CSV parser.