linux - 检查文件或用户脚本分配问题

Question

下面是我正在编写的 bash shell 脚本的作业。我有一个即使我正在使用 -f 选项，但输出 -u 信息的问题。这个类是初级类，所以请多多包涵。将不胜感激对我的代码有一些意见。感谢您抽出宝贵时间查看此内容，如果您做。

这是示例输出:

[***@***]$ chk3 -f share

share 是一个目录，它是可读的 |可写 |可执行 |阿贝克是当前登录他们的主目录是/students/abecker

这是用法

chk -f filepath

• 如果文件路径存在，输出可读的句子
• 如果是符号链接(symbolic link)，请说明。您不必继续并报告权限。
• 如果不存在，请说出来。不要继续报权限
• 报告它是什么:文件、目录或其他东西，然后继续报告权限:
• 报告您的读、写和执行访问权限的组合程序有数据。请注意，这取决于谁运行您的程序。不要试图通过查看权限作为输出来执行此操作通过 ls -l。您必须使用测试运算符来执行此操作。
• 如果文件路径不存在(并且不是符号链接(symbolic link))，你的程序应该而是在信息性错误消息中报告这一点。在这种情况下，你应该退出并出错。

chk -u user

• 如果用户存在于系统中，则报告
• 用户主目录的路径
• 如果用户当前已登录，请说明。否则，报告它们最后一次已登录。(请注意确保生成可靠且快速。)
• 如果用户不存在，则在信息性错误消息中报告此情况，并且出现错误退出。

这是我的代码

#!/bin/bash
if [ $# -gt 2 ]
then
  echo "only 2 aruments can be used"
  exit 1
fi
if [ "$1" != '-f' -a "$1" != '-u' ]
then
  echo "first argument must be -f or -u"
  exit 1
fi
if [ "$1" = '-f' -a $# -ne 2 ]
then
  echo 'Usage: chk -f [FILEPATH]'
  exit 1
fi
if [ "$1" = '-f' ]
then
  FILEPATH=$2
fi
if [ -L "$FILEPATH" ]
then
  echo  "$FILEPATH is a symbolic link"
  exit 0
elif  [ -d "$FILEPATH" ]
then
  echo -e "$(basename "$FILEPATH") is a directory and it is \c"
elif [ -f "$FILEPATH" ]
then
  echo -e "$(basename "$FILEPATH") is a file and it is \c"
else
  echo "I cannot determine what $(basename "$FILEPATH") is"
  exit 1
fi
if [ -r "$FILEPATH" ]
then
  echo -e "readable | \c"
fi
if [ -w "$FILEPATH" ]
then
  echo -e "writable | \c"
fi
if [ -x "$FILEPATH" ]
then
  echo -e "executable | \c"
fi
if [ "$1" = '-u' -a $# -eq 1 ]
then
  USER=$LOGNAME
elif [ "$1" = '-u' -a $# -eq 2 ]
then
  USER=$2
fi
USERINFO=$(grep "^$USER:" /etc/passwd)
if ! grep "^$USER:" /etc/passwd > /dev/null
then
  echo "$USER cannot be found on this system"
  exit 1
fi
if ! who | grep "^$USER " > /dev/null
then
  echo "$USER is not currently logged on and last logged on"
  echo "$(last -1 "$USER")"
  exit 0
else
  echo "$USER is currently logged in their home directory is"
  echo "$(echo "$USERINFO" | awk -F":" '{print $6}')"
fi

Answer 1

您没有将不同选项的处理放在不同的 block 中；代码只是通过所有选项的所有内容。

例如对于 -f 选项，您有:

if [ "$1" = '-f' ]
then
  FILEPATH=$2
fi

然后处理文件路径的所有选项，而不将它们放入 if 语句中，因此如果您传入 -f 或 -u，它总是传入代码:

if [ -L "$FILEPATH" ]
then
  echo  "$FILEPATH is a symbolic link"
  exit 0
elif

如果您不想将程序分解为函数，您要做的是将所有与处理 -f 选项相关的代码放入同一个 if 语句中，有点像:

if [ "$1" = '-f' ]
then
  FILEPATH=$2
  if [ -L "$FILEPATH" ]
  then
    echo  "$FILEPATH is a symbolic link"
    exit 0
  elif  [ -d "$FILEPATH" ]
  then
    echo -e "$(basename "$FILEPATH") is a directory and it is \c"
  elif [ -f "$FILEPATH" ]
  then
    echo -e "$(basename "$FILEPATH") is a file and it is \c"
  else
    echo "I cannot determine what $(basename "$FILEPATH") is"
    exit 1
  fi
  if [ -r "$FILEPATH" ]
  then
    echo -e "readable | \c"
  fi
  if [ -w "$FILEPATH" ]
  then
    echo -e "writable | \c"
  fi
  if [ -x "$FILEPATH" ]
  then
    echo -e "executable | \c"
  fi
fi # if [ "$1" = '-f' ]

同样对于-u选项，您需要将其分解为多个语句，然后处理该语句的所有选项:

if [ "$1" = 'u' ]
then
  if [ $# -eq 1 ]
  then
    USER=$LOGNAME
  elif [ $# -eq 2 ]
  then
    USER=$2
  fi
  USERINFO=$(grep "^$USER:" /etc/passwd)
  if ! grep "^$USER:" /etc/passwd > /dev/null
  then
    echo "$USER cannot be found on this system"
    exit 1
  fi
  if ! who | grep "^$USER " > /dev/null
  then
    echo "$USER is not currently logged on and last logged on"
    echo "$(last -1 "$USER")"
    exit 0
  else
    echo "$USER is currently logged in their home directory is"
    echo "$(echo "$USERINFO" | awk -F":" '{print $6}')"
  fi
fi # if [ "$1" = '-u' ]

不过，我建议将作用于选项的代码放入 shell 函数中，这样更容易阅读代码；例如

filepath() {
  FILEPATH="$1"
  if [ -L "$FILEPATH" ]
  then
    echo  "$FILEPATH is a symbolic link"
    exit 0
  elif  [ -d "$FILEPATH" ]
  then
    echo -e "$(basename "$FILEPATH") is a directory and it is \c"
  elif [ -f "$FILEPATH" ]
  then
    echo -e "$(basename "$FILEPATH") is a file and it is \c"
  else
    echo "I cannot determine what $(basename "$FILEPATH") is"
    exit 1
  fi
  if [ -r "$FILEPATH" ]
  then
    echo -e "readable | \c"
  fi
  if [ -w "$FILEPATH" ]
  then
    echo -e "writable | \c"
  fi
  if [ -x "$FILEPATH" ]
  then
    echo -e "executable | \c"
  fi
}

然后是处理代码:

if [ "$1" = '-f' ]
then
  filepath "$2"
fi

和 -u 选项类似的内容。