#!/bin/csh -f
# get_external_drive_id
# -------------------------------------------------------------------------
# Shell script to get the diskutil id of an external drive
# -------------------------------------------------------------------------
# Usage:  See Usage section below or run with -h or --help to see usage.
# Assumptions:
# Effects:
# - Echos the drive id to stdout
# Notes:
# Implementation Notes:
# Portability Issues:
# Revision History:
#   $Log$
# -----------------------------------------------------------------------------

while ($#argv > 0)
    if ("$1" == "-h" || "$1" == "--help") then
        echo "Usage: $0:t [options] drive_name"
        echo "Options:"
        echo "  -h             = Show this help text"
        echo "  --help         = Show this help text"
        exit 1
    else if ("-" == "`echo $1:q | cut -c 1`") then
        beep "Error: Invalid option: $1:q"
        $0 --help
        exit 1
    else
        # Not a recognized option.  Assume it's the first argument
        break
    endif
end

# Collect command line arguments
if ($#argv < 1) then
    beep "Error: No drive_name specified."
    $0:t --help
    exit 1
else if ($#argv > 1) then
    beep "Error: Too many arguments specified."
    $0:t --help
    exit 1
endif
set drive_name = "$1"

# This technique copied from:
# - https://egeek.me/2012/07/03/unmount-flash-drive-in-os-x/
diskutil list | awk 'BEGIN { last_disk="" } /^\/dev\/disk/ { last_disk=$1 } ($2 ~ /'"$drive_name"'/) || ($3 ~ /'"$drive_name"'/) { print last_disk; exit }'