How to compare two strings in dot separated version format in Bash?

Question

Is there any way to compare such strings on bash, e.g.: 2.4.5 and 2.8 and 2.4.5.1?

Answer 1

I implemented yet another comparator function. This one had two specific requirements: (i) I didn't want the function to fail by using return 1 but echo instead; (ii) as we're retrieving versions from a git repository version "1.0" should be bigger than "1.0.2", meaning that "1.0" comes from trunk.

function version_compare {
  IFS="." read -a v_a <<< "$1"
  IFS="." read -a v_b <<< "$2"

  while [[ -n "$v_a" || -n "$v_b" ]]; do
    [[ -z "$v_a" || "$v_a" -gt "$v_b" ]] && echo 1 && return
    [[ -z "$v_b" || "$v_b" -gt "$v_a" ]] && echo -1 && return

    v_a=("${v_a[@]:1}")
    v_b=("${v_b[@]:1}")
  done

  echo 0
}

Feel free to comment and suggest improvements.