shell $@ variable assignment and iteration

Question

function f() {
    for arg; do
        echo "$arg"
    done
}

f 'hello world' 'second arg' '3rdarg'

this works fine:

hello world
second arg
3rdarg

but when do I assign $@ to some variable, and then it goes wrong:

function f() {
    local args="$@"
    for arg in "$args"; do
        echo "$arg"
    done
}

output:

hello world second arg 3rdarg

when I unquote the $args, then each argument was split into single word:

hello
world
second
arg
3rdarg

Lastly, I wonder if there's a way to define variable like $@. Any response will be appreciated.

Answer 1

You'll need to use an array:

function f() {
    local args=("$@")             # values in parentheses
    for arg in "${args[@]}"; do   # array expansion syntax
        echo "$arg"
    done
}