v-diff.sh

#!/bin/sh
# shellcheck disable=1090

# ------------------
# Basic settings
_SCRIPT_DIR=$(dirname "$(readlink -f "$0")")
_SCRIPT_NAME=$(basename "$0")
. "${_SCRIPT_DIR}/.v-common.rc"
[ "${_LOG_PREFIX}" ] || _LOG_PREFIX="[${_SCRIPT_NAME}] "

# ------------------
# Default values
optOverwrite=""     # overwrite, (anything else)
optMkDir=""         # mkdir, (anything else)

# ------------------
# Help
if [ $# -lt 2 ] || [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
    cat << _EOF_

Usage: [VARIABLES] ${_SCRIPT_NAME} [OPTIONS] SOURCE DIFF

Create a differencing vdisk of a source vdisk.

    SOURCE      Path to the source vdisk file.
    DIFF        Path to the differencing vdisk file.

OPTIONS:

    -o,--overwrite  Overwrite the DIFF if already exists.
    -m,--mkdir      Create parent directory of the DIFF if not exists.

${_HELP_VARIABLES}

Example:

    ${_SCRIPT_NAME} x:/dir1/source.vhdx y:/dir2/diff.vhdx
    _VERBOSE=4 _NO_COLOR=0 ${_SCRIPT_NAME} -om x:/dir1/source.vhdx y:/dir2/diff.vhdx
_EOF_
    exit
fi

# ------------------
# Parse arguments
# Ref: https://www.tutorialspoint.com/unix_commands/getopt.htm
GETOPT=$(getopt -o om -l overwrite,mkdir -- "$@")
eval set -- "$GETOPT"
while true; do
    case "$1" in
    -o|--overwrite)
        optOverwrite="overwrite"; shift;;
    -m|--mkdir)
        optMkDir="mkdir"; shift;;
    --)
        shift; break;;
    *)
        echo "getopt error"; exit 1;;
    esac
done

# ------------------
# Preparation
_check_file_exist "$1"
vdiskSource=$(realpath "$1")

_check_dir_exist "$(dirname "$2")" $optMkDir
_check_file_not_exist "$2" $optOverwrite
vdiskDest=$(realpath "$2")

vdiskDest=$(toWindowsPath "$vdiskDest")
vdiskSource=$(toWindowsPath "$vdiskSource")
diskpartScript=$(cat << _EOF_
create vdisk file="${vdiskDest}" parent="${vdiskSource}"
_EOF_
)

# ------------------
# Action
_log_highlight "Differencing '${vdiskSource}' to '${vdiskDest}' ..."

_log_info "--- Diskpart script: begin"
_LOG_PREFIX="" _log_info "${diskpartScript}"
_log_info "--- Diskpart script: end"

_log_info "Running diskpart ..."

# ${_LOG_INFO_FD} is 3 (default), and >&3 is POSIX compliant.
# shellcheck disable=2039,2086
echo "${diskpartScript}" | ${_DISKPART} >&${_LOG_INFO_FD}