#!/bin/bash

END_CONDITION=end

until [ "$var1" = "$END_CONDITION" ]
# Tests condition here, at top of loop.
do
  echo "Input variable #1 "
  echo "($END_CONDITION to exit)"
  read var1
  echo "variable #1 = $var1"
  echo
done  

# ------------------------------------------- #

#  As with "for" and "while" loops,
#+ an "until" loop permits C-like test constructs.

LIMIT=10
var=0

until (( var > LIMIT ))
do  # ^^ ^     ^     ^^   No brackets, no $ prefixing variables.
  echo -n "$var "
  (( var++ ))
done    # 0 1 2 3 4 5 6 7 8 9 10 


exit 0