BashReference.md

Bash Reference

• $@ : fetch all params
• myArray=(1 2 3) : array definition
• ${myArray[@]:1:2} : slicing arrays using bash parameter expansion
• myArray=( "$@" ): command line arguments as an array
• $#: number of parameters
• $?: exit value of the previous command
• local varName: means to define a variable with function scope
• case statement:

case $varName in
	"val1" ) 
	   #do something
	   ;;
	 * )
	   # default handler
	   ;;
esac

• Array definition

arrayVariable=( "val1" "val2" "val3" )

• For loop

for var in $arrayVariable[@]; do
	#use the $var
done

• getopts: for command line parameter handling

Getopts example

function do1() {
  echo "doing one..."
}

function do2() {
  echo $#
  echo $@
  echo "doing two... with arg ${@}"
}

function do3() {
  echo "doing three... with optional arg $2"
}

function handle_opts() {
  while getopts "de:f" opt; do
    case $opt in
      d) do1 ;;
      e) do2 "$OPTARG" ;;
      f) do3 ;;
    esac
  done
}

handle_opts $@

Links

http://stackoverflow.com/questions/12711786/bash-convert-command-line-arguments-into-array http://stackoverflow.com/questions/1335815/how-to-slice-an-array-in-bash Bash Reference