#!/bin/bash

# Sets a password environment variable

self="$(readlink -f -- "$BASH_SOURCE")"

force=

test _"$1" = _- && { force=1; shift;}

test "$#" -ge 1 || \

{ echo "Usage: . $self env_var_name [msg] (note initial \".\")" >&2; exit 2;}

msg="$2"

test -n "$msg" || msg="$1"

function trace()

{

    { for arg in "$@"; do printf "%q " "$arg"; done; echo;} >&2

}

if test -n "$force" -o -z "${!1+t}"; then # env var with name $1 is unset

    if test -n "$force"; then action="change the saved value for"

    else action="avoid having to reenter"

    fi

    echo " To $action $msg password, run: " >&2

    trace . "$self" - "$@"

    read -s -p "Enter $msg password: "; echo

    export "$1"="$REPLY"

fi