检查参数的正确数量 [英] Checking for the correct number of arguments

问题描述

我如何检查参数的正确数量(一个参数).如果有人试图调用脚本而没有传入正确数量的参数，并检查以确保命令行参数确实存在并且是一个目录.

How do i check for the correct number of arguments (one argument). If somebody tries to invoke the script without passing in the correct number of arguments, and checking to make sure the command line argument actually exists and is a directory.

推荐答案

#!/bin/sh
if [ "$#" -ne 1 ] || ! [ -d "$1" ]; then
  echo "Usage: $0 DIRECTORY" >&2
  exit 1
fi

翻译:如果参数数量不(数字)等于 1 或第一个参数不是目录，则将用法输出到 stderr 并以失败状态代码退出.

Translation: If number of arguments is not (numerically) equal to 1 or the first argument is not a directory, output usage to stderr and exit with a failure status code.

更友好的错误报告:

#!/bin/sh
if [ "$#" -ne 1 ]; then
  echo "Usage: $0 DIRECTORY" >&2
  exit 1
fi
if ! [ -e "$1" ]; then
  echo "$1 not found" >&2
  exit 1
fi
if ! [ -d "$1" ]; then
  echo "$1 not a directory" >&2
  exit 1
fi

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