#!/bin/bash

# Prompt the user for a start/end numbers and print all the odd numbers between
# them.  If start > end, switch start and end.
# Example output:
# > ./b.sh 
# Start? 0
#   End? 20
# 1  3  5  7  9  11  13  15  17  19 

# Use read to prompt for a start and ending value:
read -p "Start? " start;
read -p "  End? " end;

# If the start > end, switch the two:
if (( start > end )); then
  let t=start;
  let start=end;
  let end=t;
fi

# If start is an even number, increment by one:
if (( start%2 == 0 )); then let start++; fi

# Use a C style for loop to loop through the odd numbers until start > end.
# Increment start by two each time through the loop.  Use echo to print the
# number followed by a space, but without a newline.
for (( ; start <end; start+=2 )) {
  echo -n $start " ";
}

# After the loop is finished use echo to print a newline.
echo ;