Re: pipe and resend mail. was [noob question on filtering and sending mail to bdd or rest request]

[Viktor Dukhovni]

On Wed, Dec 21, 2016 at 05:00:19PM +0100, Stéphane MERLE wrote:

> lemail=$(cat)

Instead of buffering the message into a shell variable, buffer it
into a temporary file (and set a "trap" command to delete the file).

You can then inspect the file content before sending the right
message.

It is possible to pre-unlink the file, while keeping an open handle:

    msg=$(mktemp /tmp/msg.XXXXXX) || exit 75
    cat > $msg || { rm $msg; exit 75; }
    exec 3< $msg || { rm $msg; exit 75; }
    rm $msg

You can then read the file multiple times by rewinding file descriptor 3:

    perl -e 'open IN, "<&", 3; seek(IN, 0, 0);'
    if grep 'pattern' <& 3 >/dev/null; then
        set -- "$@" "$additional_recipient"
    fi

And finally

    perl -e 'open IN, "<&", 3; seek(IN, 0, 0);'
    exec sendmail -i "$@" <&3

-- 
        Viktor.