Bash pass array as function parameter

bash

In function body, refer array parameter using ${!1} instead of ${1}.

Example:

function a(){
    x=$1
    y=$2
    echo "x = ${x} y = ${y}" 
}
a hal eos
arr="10 11 12 13"
function b(){
    nums=$(echo ${!1}| tr ' ' '\n')
    for e in "${nums[@]}"
    do
        echo "$e"
    done
}
b arr

Output:

x = hal y = eos      
10          
11
12                                                                                           
13  

Another complex exmaple:

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

Modified from this example, give a more complicated exmaple below.

The idea is:
1. define a function f in file A
2. define a function g in file B
3. in function f:
- call function g in B
- pass g an argument of string (seperated by spaces)
- g parses the string argument and display it as an array of elements

• the 1st file i have is called main.sh:

#!/bin/bash
arr="10 11 12 13"
function f(){
    source test.sh
    takes_ary_as_arg $1
}
f arr

• the 2nd file is called test.sh:

#!/bin/bash
takes_ary_as_arg(){
    declare -a argAry1=("${!1}")
    nums=(`echo "${argAry1[@]}"`)
    for i in "${nums[@]}"
    do
        echo $i
    done
}

• Run command ./main.sh
  Output:

10
11
12
13

Reference

http://stackoverflow.com/questions/1063347/passing-arrays-as-parameters-in-bash