#!/bin/sh
#
# This file is part of TCOS
#
#  (emulate /bin/seq with a shell script)

MAX=$1
NUM=1
INC=1

if [ "$MAX" = "" ]; then
  echo "TCOS seq number generator"
  echo ""
  echo "Print numbers from FIRST to LAST, in steps of INCREMENT."
  echo "Usage: seq LAST"
  echo "  or:  seq FIRST LAST"
  echo "  or:  seq FIRST INCREMENT LAST"
  exit 1
fi

if [ $# = 1 ]; then
  MAX=$1
elif [ $# = 2 ]; then
  NUM=$1
  MAX=$2
elif [ $# = 3 ]; then
  NUM=$1
  INC=$2
  MAX=$3
fi

if [ $MAX -gt 100 ] || [ $MAX -lt 1 ]; then
  echo "ERROR: Max number must be in 1-100"
  exit 1
fi

if [ $INC -lt 1 ] ; then
  echo "ERROR: Increment must be big than 1"
  exit 1
fi

while [ $NUM -le $MAX ]; do
  echo $NUM
  NUM=$((NUM +INC))
done