Parse key=val config file

parse_config.sh

parse_config() {
    _config_file="${1:?Error: Profile config file}"
    
    # check if the config file accessible
    [ -r "${_config_file}" ] || {
        printf "%s\n" "Error: Given config file ( ${_config_file} ) is not readable."
        return 1
    }
 
    # Setting 'IFS' tells 'read' where to split the string.
    while IFS='=' read -r key val; do
        # Skip Lines starting with '#'
        # Also skip lines if key and val variable is empty
        { [ -n "${key}" ] && [ -n "${val}" ] && [ -n "${key##\#*}" ] ;} || continue

        # trim all leading white space
        key="${key#${key%%[![:space:]]*}}"
        val="${val#${val%%[![:space:]]*}}"
        
        # trim all trailing white space
        key="${key%${key##*[![:space:]]}}"
        val="${val%${val##*[![:space:]]}}"
        
        # '$key' stores the key and '$val' stores the value.
        # Throw a warning if cannot export the variable
        export "${key}=${val}" 2>/dev/null ||
            printf "%s\n" "Warning: ${key} is not a valid variable name."
    done < "${_config_file}"
}