iterate over sh arguments and concat them (sh !!! not bash)

sh_arg_iteration.sh

#!/bin/sh

# exit code
E_BADARGS=85

ARG_LIST=""
index=0 # Reset count.
for arg in "$@"
do
    #skipp first argument
    if [ "$index" -eq "0" ]; then
        let "index+=1"
        continue
    fi

    if [ "$index" -eq "1" ]; then
        ARG_LIST=$ARG_LIST$arg
        let "index+=1"
        continue
    fi

    ARG_LIST=$ARG_LIST" "$arg

    let "index+=1"
done

echo "ARG_LIST"