POSIX-compatible looping over

posix_for_range.sh

#!/usr/bin/env sh

# POSIX-compatible scripts cannot use the non-POSIX
# `seq` command or any shell-specific functionality.
# This is a helper function to make number lists to
# be used in for-loops. This is a reduced subset of
# the functionality `seq` provides, but is portable.
range() {
	loopcnt=$1
	while [ "$loopcnt" -le "$2" ]
	do
		echo "$loopcnt"
		loopcnt=$(( loopcnt + 1 ))
	done
}

# Usage example
for a in $(range 1 64)
do
	echo $a
done