#!/bin/bash
shopt -s extglob
var1=123abcd456
echo ${var1//+([[:digit:]])/}
var2=ABC123EFG
echo ${var2//+([[:upper:]])/}
var3=abc?ABC\!123.de\;gh\:45,6
echo ${var3//+([[:punct:]])/}
var4="AB c d 1 2 3"   #Ne pas oublier les " "
echo ${var4//+([[:space:]])/}