shell中判断字符串是否为空
时间: 2023-11-28 09:04:03 浏览: 82
shell中字符串、数值的比较.rar_shell中字符串、数值的比较
在shell中,你可以使用不同的方法来判断字符串是否为空。以下是几种常用的方法:
1. 使用if和test命令的-z参数:`if test -z "$str"; then echo "Empty"; fi` [1]
2. 使用if和方括号来判断:`if [ -z "$str" ]; then echo "Empty"; fi` [2]
3. 使用双中括号来判断:`if [[ -z "$str" ]]; then echo "Empty"; fi` [3]
以上三种方法都可以判断一个字符串是否为空。需要注意的是,在比较字符串时,最好将变量两端用双引号括起来,以避免一些意外的错误。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
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