检查正确数量的参数

Question

我如何检查正确的参数数量（一个参数）。如果有人试图在不传递正确数量的参数的情况下调用脚本，并检查以确保命令行参数确实存在并且是目录。

Answer 1

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

转换：如果参数数量（数值）不等于1或第一个参数不是目录，则输出使用到stderr并退出并显示失败状态代码。

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

Answer 2

cat script.sh

    var1=$1
    var2=$2
    if [ "$#" -eq 2 ]
    then
            if [ -d $var1 ]
            then
            echo directory ${var1} exist
            else
            echo Directory ${var1} Does not exists
            fi
            if [ -d $var2 ]
            then
            echo directory ${var2} exist
            else
            echo Directory ${var2} Does not exists
            fi
    else
    echo "Arguments are not equals to 2"
    exit 1
    fi

执行它如下 -

./script.sh directory1 directory2

输出将像 -

directory1 exit
directory2 Does not exists

Answer 3

您可以使用“$#”检查在命令行中传递的参数总数。例如，我的s​​hell脚本名称是hello.sh

sh hello.sh hello-world
# I am passing hello-world as argument in command line which will b considered as 1 argument 
if [ $# -eq 1 ] 
then
    echo $1
else
    echo "invalid argument please pass only one argument "
fi

输出将是hello-world