Call a function with an argument inside a function that needs another argument

Question

I don't know how else to word this so I'll do my best to explain. I have a function

main()
{

        if [[ "$1" = "-f" ]]
        then
                ($sendFirstEmail) "$1"

        elif [[ "$1" = "-s" ]]
        then
                ($sendSecondEmail) "$1"

        elif [[ "$1" = "-k" ]]
        then
                ($sendKillEmail) "$1"
        else
                echo "valid input not provided"
        fi
}

That I call like this main "$1" what I need to do is pass another argument into the other functions inside the main function that also takes the first argument passed to it. $sendFirstEmail etc. are the names of the other functions that also take the first argument passed to them. In essence this is how I want to call the script ./sendEmail.sh -f [email protected] Is this possible or is there a better way to achieve what I'm trying to do?

Answer 1

You can pass the position parameter(s) to them just like you have done with main however not outside the subshell.

main()
{
    if [[ "$1" == "-f" ]]
    then
        sendFirstEmail "$1"

    elif [[ "$1" == "-s" ]]
    then
        sendSecondEmail "$1"

    elif [[ "$1" == "-k" ]]
    then
        sendKillEmail "$1"
    else
        echo "valid input not provided"
    fi
}

I'm not sure what the purpose of the subshells were so I have removed them but if you do in fact need a subshell for some reason just put the parameter(s) inside it:

( sendFirstEmail "$1" )

---

As Kusalananda points out this particular example is better suited for a case construct rather than an if (see 3.2.4.2 Conditional Constructs)

main()
{
    case $1 in
        -f) sendFirstEmail "$1";;
        -s) sendSecondEmail "$1";;
        -k) sendKillEmail "$1";;
        *)  echo "valid input not provided" >&2;;
    esac
}

---

Or better yet, getopts

main()
{
    if getopts fsk opt; then
        case $opt in
            f)  sendFirstEmail "$1";;
            s)  sendSecondEmail "$1";;
            k)  sendKillEmail "$1";;
            *)  echo "valid input not provided" >&2;;
        esac
    fi
}

---

In the event you are actually trying to provide a second argument as Tim has suggested you could use the getopts optarg feature:

main()
{
    if getopts f:s:k: opt; then
        case $opt in
            f)  sendFirstEmail "$OPTARG";;
            s)  sendSecondEmail "$OPTARG";;
            k)  sendKillEmail "$OPTARG";;
            *)  echo "valid input not provided" >&2;;
        esac
    fi
}

In this case you would run main like:

main -f 'option to the -f argument'

Answer 2

Could you just pass 2 arguments to your main function?

main()
{
    arg1=$1
    arg2=$2

    if [[ "$arg1" = "-f" ]]
    then
            ($sendFirstEmail "$arg2")

    elif [[ "$arg1" = "-s" ]]
    then
            ($sendSecondEmail "$arg2")

    elif [[ "$arg1" = "-k" ]]
    then
            ($sendKillEmail "$arg2")
    else
            echo "valid input not provided"
    fi
}

In this case, $arg2 in main() becomes $1 inside the various send*Email commands.

Answer 3

At the risk of repeating what others have said: if, as you say, you are calling the script as (for example)  ./sendEmail.sh -f [email protected], then you have to call

main "$1" "$2"

and change main() as follows:

main()
{
        if [[ "$1" = "-f" ]]
        then
                sendFirstEmail "$2"
 
        elif [[ "$1" = "-s" ]]
        then
                sendSecondEmail "$2"
 
        elif [[ "$1" = "-k" ]]
        then
                sendKillEmail "$2"
        else
                echo "valid input not provided"
        fi
}

so the second argument to the (outermost) script becomes the second argument to main(), and subsequently the (one and only) argument to the innermost functions.

I have changed $(function_name) to function_name because you said that $(function_name) didn’t work.