1: #!/bin/ksh
   2: # Example 17
   3: 
   4: # Shell idioms: multiple ways to accomplish
   5: # common tasks
   6: 
   7: # For example, test the first character in a string 
   8: 
   9: var=$1
  10: echo "var=\"$var\""
  11: 
  12: # Use 'cut' - works everywhere, but uses an an extra process
  13: # for a trivial job.
  14: echo
  15: echo "Using 'cut'"
  16: if [ "`echo $var | cut -c1`" = "/" ] ; then
  17:    echo "starts with /"
  18: else
  19:    echo "doesn't start with /"
  20: fi
  21: 
  22: # Use 'case' with a pattern.  Works everywhere. 
  23: echo
  24: echo "Using 'case'"
  25: case $var in
  26: /*) echo "starts with /" ;;
  27: *)  echo "doesn't start with /" ;;
  28: esac
  29: 
  30: # Use POSIX variable truncation - works with ksh and bash and POSIX-compliant sh
  31: # Dave Taylor in "Wicked Cool Shell Scripts" likes this one.
  32: echo
  33: echo "Using POSIX variable truncation"
  34: if [ "${var%${var#?}}" = "/" ]; then
  35:    echo "starts with /"
  36: else
  37:    echo "doesn't start with /"
  38: fi
  39: 
  40: # Use ksh/bash pattern template match inside of [[ ]]
  41: echo
  42: echo "Using ksh/bash pattern match in [[ ]]"
  43: if [[ $var = /* ]]; then
  44:    echo "starts with /"
  45: else
  46:    echo "doesn't start with /"
  47: fi
  48: 
  49: # Use ksh (93 and later) and bash variable substrings
  50: echo
  51: echo "Using ksh93/bash variable substrings"
  52: if [ "${var:0:1}" = "/" ]; then
  53:    echo "starts with /"
  54: else
  55:    echo "doesn't start with /"
  56: fi