#!/bin/ksh
# Example 17

# Shell idioms: multiple ways to accomplish
# common tasks

# For example, test the first character in a string 

var=$1
echo "var=\"$var\""

# Use 'cut' - works everywhere, but uses an an extra process
# for a trivial job.
echo
echo "Using 'cut'"
if [ "`echo $var | cut -c1`" = "/" ] ; then
   echo "starts with /"
else
   echo "doesn't start with /"
fi

# Use 'case' with a pattern.  Works everywhere. 
echo
echo "Using 'case'"
case $var in
/*) echo "starts with /" ;;
*)  echo "doesn't start with /" ;;
esac

# Use POSIX variable truncation - works with ksh and bash and POSIX-compliant sh
# Dave Taylor in "Wicked Cool Shell Scripts" likes this one.
echo
echo "Using POSIX variable truncation"
if [ "${var%${var#?}}" = "/" ]; then
   echo "starts with /"
else
   echo "doesn't start with /"
fi

# Use ksh/bash pattern template match inside of [[ ]]
echo
echo "Using ksh/bash pattern match in [[ ]]"
if [[ $var = /* ]]; then
   echo "starts with /"
else
   echo "doesn't start with /"
fi

# Use ksh (93 and later) and bash variable substrings
echo
echo "Using ksh93/bash variable substrings"
if [ "${var:0:1}" = "/" ]; then
   echo "starts with /"
else
   echo "doesn't start with /"
fi