util

#!/bin/sh

set -eu

check_existence()
{
  set +e
  which "$1" > /dev/null 2>&1
  exists=$?
  if [ ! "$exists" -eq "0" ];
  then
    log_end "$1 not found; see the README for dependencies" 1>&2
    exit 1
  fi
  set -e
}

show_help()
{
  log "usage: $0 [OPTION...]"
  log
  log "  -h         Show this help message"
  log "  -g <dev>   Set GRUB target device (default: ${grub_device:-undefined})"
  log "  -r <dev>   Set root filesystem target device (default: ${root_mount:-undefined})"
  log "  -t <type>  Set root filesystem type (default: ${root_type:-undefined})"
  log "  -G         Use the graphical NixOS ISO (default: ${iso:-undefined})"
  log "  -c         Set extra Nix config file (default: ${extra_config:-undefined})"
  log "  -d         Prepare for use with Digital Ocean (default: ${digitalocean:-undefined})"
  log "  -w <dir>   Specify the working directory (default: random in /tmp)"
  exit 1
}

log()
{ printf ">>> %s\n" "$*"; }
log_start()
{ printf ">>> %s" "$*"; }
log_end()
{ printf "%s\n" "$*"; }