shell中判断空字符串和有趣的空字符串

Introduction

Shell 中判断空字符串 以及有趣的空字符串

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判断字符串是否为空

Example1

if [[ -z "$str" ]] then echo "1 empty" fi

Example2

if [[ "$str"x = "x" ]] then echo "2 empty" fi

Example3

if [[ "$str" = "" ]] then echo "2 empty" fi

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有趣的 空字符串

root@pts/4 $ cat /tmp/lc-7.sh #!/usr/bin/env bash str=$1 if [[ "$str" = "" ]] then echo "1 empty" fi if [[ "$str" = " " ]] then echo "2 empty" fi if [[ "$str" = "0" ]] then echo "3 empty" fi if [[ "$str" = "00" ]] then echo "4 empty" fi if [[ "$str" -eq 0 ]] then echo "5 empty" fi if [[ "$str" -eq 000 ]] then echo "6 empty" fi if [[ "$str" -eq '0' ]] then echo "7 empty" fi if [[ "$str" -eq '00' ]] then echo "8 empty" fi ## show results root@pts/4 $ bash /tmp/lc-7.sh 1 empty 5 empty 6 empty 7 empty 8 empty

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从最后的结果中你发现了什么？

欢迎大家留言讨论

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简书地址：shell中判断空字符串和有趣的空字符串

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