我有一个bash脚本，每天晚上通过cron备份Minecraft服务器，脚本如下：

#!/usr/bin/env bash
#
# Usage:
#   backup_server.sh <name>
#
# Options:
#   -h, --help                 Show this screen.
#   --version                  Show version.

set -euo pipefail

#shellcheck disable=SC1091
source /opt/minecraft/bin/docopts.sh
source /opt/minecraft/scripts/mc_functions.sh

rcon() {
  local command=$1
  if [ "$server_name" != "proxy" ] && mc_server_online "$server_name" ; then
    /opt/minecraft/bin/mcrcon "$command"
  fi
}

main() {
  local version='1.0.0'
  usage=$(docopt_get_help_string "$0")
  eval "$(docopts -A ARGS -V "$version" -h "$usage" : "$@")"

  local server_name=${ARGS[<name>]}
  local source=$MC_SERVER_ROOT/$server_name
  local destination=$MC_BACKUP_ROOT/$server_name

  [ -d "$source" ] || { 
    printf "A server named '%s' does not exist.\n" "$server_name" >&2
    exit 1
  }

  mc_set_rcon_credentials "$server_name" || { 
    printf "Failed to set the rcon credentials for the server '%s'.\n" "$server_name" >&2
    exit 1
  }

  rcon "save-off"
  rcon "save-all"
  mkdir -p "$destination"
  tar -cpvzf "$destination/$(date +%F-%H-%M).tar.gz" "$source" >&2
  rcon "save-on"

  unset MCRCON_PASS
  unset MCRCON_PORT

  find "$MC_BACKUP_ROOT" -type f -mtime +7 -name "*.gz" -delete
}

main "$@"

以前，我没有完全限定source命令中脚本的路径或mcrcon的路径，因为这些路径在我的路径中，当从终端运行脚本时，脚本找到它们没有问题。
然而，当从cron运行脚本时，脚本会失败，因为它找不到可执行文件或脚本。我猜这是因为cron不能读取或使用$PATH？
我的crontab看起来像这样：

0 1 * * * bash /opt/minecraft/scripts/backup_server.sh proxy
# There's a few other commands here identical to this one except for the server name.

有人能解释一下为什么我需要在使用cron时完全限定脚本/可执行文件的路径，或者建议一种不那么乏味的方法来完成这个任务吗？