Function with optional positional argument

Question

With the following bash function, how can I get the function allow $2 to be optional, defaulting its value when nothing is passed for that argument ?

serputil ()
 {
  local opstring="$1"
  local sersel="$2"
 }

Answer 1

Like this, using bash parameter expansion:

iserputil () {
  local opstring="$1"
  local sersel="${2:-DEFAULT}"
  echo "$opstring"
  echo "$sersel"
 }

iserputil ok

Output

ok
DEFAULT

If you run

iserputil ok ko

You will get

ok
ko