Help me improve my first shell script

pfr

So I have been testing out a few things I've learned from playing with scripts I've found, and have finally put a script together myself, from scratch. It's pretty basic, but it's useful for me.

The email script below is an interactive way of dealing with my various email addresses using heirloom-mailx.

Side Note:

Because mailx is already installed on NetBSD at /usr/bin/mailx, a simple script called hmail is used to unset the use of mailrc (so not to conflict with the systems mailx program) and to specify the correct mailx to use. In my case, heirloom-mailx is located in /usr/pkg/bin/mailx

Any hints on how to generally improve the script are welcome. I do however wish to solve one particular issue. That is, being able to send mail using the -c flag for sending Carbon Copies, and the -a flag for sending mail with attachments.

The Script:

#!/bin/sh
#
# This is my first ever shell script. It is a simple helper script
# for interacting with my various email accounts using heirloom-mailx
#
#  https://codeberg.org/pfr

set -eu -o pipefail

clear

echo
read -p "Select from the following:

1) Go to your Inbox
2) Compose Email
3) Quit

> " action

clear

if [ "$action" = "1" ]; then
    echo
    read -p "Which Inbox?

1) d.a.p@gmail
2) dve.pfr@gmail
3) pfr@sdf.org

> " inbox

clear

    if [ "$inbox" = "1" ]; then
        hmail -A gmail
    fi

    if [ "$inbox" = "2" ]; then
        hmail -A dve.pfr
    fi

    if [ "$inbox" = "3" ]; then
        hmail -A sdfmail
    fi

fi

if [ "$action" = "2" ]; then
    echo
    read -p "Send mail from:

1) d.a.p@gmail
2) dve.pfr@gmail
3) pfr@sdf.org

> " sender

clear

    if [ "$sender" = "1" ]; then
        echo
        read -p "Send mail to: " address
        hmail -A gmail $address
    fi

    if [ "$sender" = "2" ]; then
        echo
        read -p "Send mail to: " address
        hmail -A dve.pfr $address
    fi

    if [ "$sender" = "3" ]; then
        echo
        read -p "Send mail to: " address
        hmail -A sdfmail $address
    fi
fi

if [ "$action" = "3" ]; then
    exit
fi

email

I had success with the following alterations, which allows me to choose to add one attachment and one CC to the email. However, it the script will fail if either of the CC or Attachment fields are left empty.

    if [ "$sender" = "1" ]; then
        echo
        read -p "Send mail to: " address
        read -p "Send CC: " cc_addr
        read -p "Attachemnt: " file
        hmail -A gmail -a $file -c $cc_addr $address
    fi

    if [ "$sender" = "2" ]; then
        echo
        read -p "Send mail to: " address
        read -p "Send CC: " cc_addr
        read -p "Attachment: " file
        hmail -A dve.pfr -a $file -c $cc_addr $address
    fi

    if [ "$sender" = "3" ]; then
        echo
        read -p "Send mail to: " address
        read -p "Send CC: " cc_addr
        read -p "Attachment: " file
        hmail -A sdfmail -a $file -c $cc_addr $address
    fi

I'm guessing it possibly needs an if+else statement specifying what to do if fields are left empty? Not sure how I'd get it to allow for multiple attachments or CC's though...

I guess I can always add attachments while composing the email with:
~@ /path/to/attachment however I'd rather specify them all at the beginning if possible.

Hopefully some of you smart programmers can give me some tips. Any help is appreciated 🙂

rvp

pfr

email

#!/bin/sh

set -eu
P1="Account?

1) d.a.p@gmail
2) dve.pfr@gmail
3) pfr@sdf.org

> "
clear; read -p "$P1" var
case $var in
1)	acct="gmail"
	;;
2)	acct="dve.pfr"
	;;
3)	acct="sdfmail"
	;;
*)	echo >&2 "$0: $var: invalid choice"
	exit 1
	;;
esac

exec hmail -A "$acct" "$@"

Reading email:

$ email

Sending:

$ email -a file.txt -c x@x.com u1@foo.com u2@bar.com [...]

pfr

rvp
That's a neat alternative solution, and probably better than what my script is doing. But it's lacking a quit option.

I intentionally designed it so that my script would run again immediately after closing one inbox so I could check the next inbox, hence the need for an option to exit the loop.

Also, I was enjoying playing with the interactive nature of the script and avoiding the need to enter any command line options etc.

EDIT 1:

Thanks for the email. That interactive script works a charm, aside from still missing the loop/quit option.

I thought I may as well include the script @rvp sent me here for anyone curious, and so I can revisit this thread again in the future.

#!/bin/sh

set -eu

die() {
        echo >&2 "$0: $*"
        exit 1
}

get_addr() {            # space-separated To-address list
        local var
        read -p "To addrs: " var
        [ -n "$var" ] || die "To-address is empty!"
        echo "$var"
}

get_attach() {          # f1 file* => -a f1 -a filea -a fileb
        local v var
        read -p "Attachments: " var
        set -- $(eval echo $var)        # expand FNs--no spaces allowed
        for v
        do      [ -f $v -a -s $v ] && echo "-a $v" ||
                die "$v: invalid file"
        done
}

get_cc() {              # addr1 addr2 => -c addr1,addr2
        local v var
        read -p "CC addrs: " var
        set -- $var
        [ $# -eq 0 ] && return 0        # blank CC: is OK
        var="$1"; shift
        for v
        do      var="$var,$1"
                shift
        done
        echo "-c $var"
}

P1="Account?

1) d.a.p@gmail
2) dve.pfr@gmail
3) pfr@sdf.org

> "

P2="Action?

1) Read
2) Compose

> "

clear; read -p "$P1" var
case $var in
1)      acct="gmail"
        ;;
2)      acct="dve.pfr"
        ;;
3)      acct="sdfmail"
        ;;
*)      die "$var: invalid choice"
        ;;
esac

read -p "$P2" var
case $var in
1)      addr="" attach="" cc=""
        ;;
2)      addr=$(get_addr)
        attach=$(get_attach)
        cc=$(get_cc)
        ;;
*)      die "$var: invalid choice"
        ;;
esac

exec hmail -A "$acct" "$@" $attach $cc $addr

EDIT 2:

And for an interactive version that loop's until you hit q to quit we have this:

#!/bin/sh

set -eu

die() {
        echo >&2 "$0: $*"
        exit 1
}

get_addr() {            # space-separated To-address list
        local var
        read -p "To addrs: " var
        [ -n "$var" ] || die "To-address is empty!"
        echo "$var"
}

get_attach() {          # f1 file* => -a f1 -a filea -a fileb
        local v var
        read -p "Attachments: " var
        set -- $(eval echo $var)        # expand FNs--no spaces allowed
        for v
        do      [ -f $v -a -s $v ] && echo "-a $v" ||
                die "$v: invalid file"
        done
}

get_cc() {              # addr1 addr2 => -c addr1,addr2
        local v var
        read -p "CC addrs: " var
        set -- $var
        [ $# -eq 0 ] && return 0        # blank CC: is OK
        var="$1"; shift
        for v
        do      var="$var,$1"
        done
        echo "-c $var"
}

P1="Account?

1) d.a.p@gmail
2) dve.pfr@gmail
3) pfr@sdf.org

> "

P2="Action?

1) Read
2) Compose

> "

while :
do

clear; read -p "$P1" var
case $var in
1)      acct="gmail"
        ;;
2)      acct="dve.pfr"
        ;;
3)      acct="sdfmail"
        ;;
q)      break                   # loop
        ;;
*)      die "$var: invalid choice"
        ;;
esac

read -p "$P2" var
case $var in
1)      addr="" attach="" cc=""
        ;;
2)      addr=$(get_addr)
        attach=$(get_attach)
        cc=$(get_cc)
        ;;
q)      break                   # loop
        ;;
*)      die "$var: invalid choice"
        ;;
esac

hmail -A "$acct" "$@" $attach $cc $addr || true
done

Big thanks to @rvp for completely revamping my script into a working solution which does exactly what I wanted it to do.

Some questions may follow.... 😉

rvp

pfr In the EDIT 2: code, that assignment in the for loop in get_cc() is not what I sent you. It should be: var="$var,$v"

pfr

rvp Hmmmm perhaps I missed that when copying it over from my email.. It seemed to work though, but I haven't tested it extensively with multiple Cc'd. Thanks for the heads up!