${parameter:-word}	Use Default Values.
${parameter:=word}	Assign Default Values.
${parameter:?[word]}	Indicate Error if Null or Unset.
${parameter:+word}	Use Alternative Value.

${#parameter}		String Length.
${parameter%word}	Remove Smallest Suffix Pattern.
${parameter%%word}	Remove Largest Suffix Pattern.
${parameter#word}	Remove Smallest Prefix Pattern.
${parameter##word}	Remove Largest Prefix Pattern.

./cmd 123 a b cd
#!/bin/sh
echo ${#1}		# 3 (length of first parameter)

# pattern match check the following site:
# http://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_13

f='/home/cpfong/test.txt'
base=$(printf %s ${f##*/})
dir=$(printf %s ${f%/*})