Passing arrays as parameters in bash

Note: This is the somewhat crude solution I posted myself, after not finding an answer here on Stack Overflow. It allows for only one array being passed, and it being the last element of the parameter list. Actually, it is not passing the array at all, but a list of its elements, which are re-assembled into an array by called_function(), but it worked for me. Somewhat later Ken posted his solution, but I kept mine here for "historic" reference.

calling_function()
{
    variable="a"
    array=( "x", "y", "z" )
    called_function "${variable}" "${array[@]}"
}

called_function()
{
    local_variable="${1}"
    shift
    local_array=("${@}")
}

You can pass multiple arrays as arguments using something like this:

takes_ary_as_arg()
{
    declare -a argAry1=("${!1}")
    echo "${argAry1[@]}"

    declare -a argAry2=("${!2}")
    echo "${argAry2[@]}"
}
try_with_local_arys()
{
    # array variables could have local scope
    local descTable=(
        "sli4-iread"
        "sli4-iwrite"
        "sli3-iread"
        "sli3-iwrite"
    )
    local optsTable=(
        "--msix  --iread"
        "--msix  --iwrite"
        "--msi   --iread"
        "--msi   --iwrite"
    )
    takes_ary_as_arg descTable[@] optsTable[@]
}
try_with_local_arys

will echo:

sli4-iread sli4-iwrite sli3-iread sli3-iwrite  
--msix  --iread --msix  --iwrite --msi   --iread --msi   --iwrite

Edit/notes: (from comments below)

  • descTable and optsTable are passed as names and are expanded in the function. Thus no $ is needed when given as parameters.
  • Note that this still works even with descTable etc being defined with local, because locals are visible to the functions they call.
  • The ! in ${!1} expands the arg 1 variable.
  • declare -a just makes the indexed array explicit, it is not strictly necessary.

Tags:

Arrays

Bash