[Happy BASH] BASH中的$*和$@的区别

最新推荐文章于 2024-10-29 15:31:47 发布

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本文通过一段Bash脚本示例详细解释了$@与$*在处理命令行参数时的不同行为。演示了如何使用这两个变量来分别获取未被合并的参数列表及合并后的参数字符串。

首先来看一段BASH代码：

echo "\$@=" $@
echo "\"\$@\"=" "$@"

echo "print each param from \$@"
for var in $@
do
        echo $var
done

echo "print each param from \"\$@\""
for var in "$@"
do
        echo "$var"
done

echo "print each param from \$*"
for var in $*
do
        echo "$var"
done

echo "print each param from \"\$*\""
for var in "$*"
do
        echo "$var"
done

执行./test.sh "a a" b c d，将会得到以下输出：

$@= a a b c d
"$@"= a a b c d
print each param from $@
a
a
b
c
d
print each param from "$@"
a a
b
c
d
print each param from $*
a
a
b
c
d
print each param from "$*"
a a b c d

总结，总是要用"$@" （双括号括起来的$@），所有参数的串联字符串，则用"$*" （仍然是双括号括起来的$*）。