满足条件后如何退出/中断嵌套的 if-else 语句答案

【问题标题】：How to exit/break from nested if-else statement once conditions are met满足条件后如何退出/中断嵌套的 if-else 语句
【发布时间】：2017-09-14 07:46:44
【问题描述】：

我有一个使用嵌套 if-else 语句来搜索文件的脚本。一旦满足任何一个嵌套语句的条件，我希望脚本退出。

但脚本仍会继续运行所有剩余的 if-else 语句。

我已经使用 exit 0 和 return 0 进行了测试，但都不起作用。

这是脚本：

#!/bin/sh

PATH1=/filer1_vol1_dir1
PATH2=/filer2_vol1_dir1
PATH3=/filer3_vol1_dir2
PATTERN=fruits

find $PATH1 -type f -name "*$PATTERN*" -exec ls -l {} \; >> /tmp/${PATTERN}_search

if [[ -s /tmp/${PATTERN}_search && `grep -i apples /tmp/${PATTERN}_search` ]]
then
        echo "Matching files have been found under $PATH1"
        cat /tmp/${PATTERN}_search
        return 0
else
        echo "No matching files, proceeding to search $PATH2"
        find $PATH2 -type f -name "*$PATTERN*" -exec ls -l {} \; >> /tmp/${PATTERN}_search

        if [[ -s /tmp/${PATTERN}_search && `grep -i apples /tmp/${PATTERN}_search` ]]
        then
                echo "Matching files have been found under $PATH2"
                cat /tmp/${PATTERN}_search
                return 0
        else
                echo "No matching files, proceeding to search $PATH3"
                find $PATH3 -type f -name "*$PATTERN*" -exec ls -l {} \; >> /tmp/${PATTERN}_search

                if [[ -s /tmp/${PATTERN}_search && `grep -i apples /tmp/${PATTERN}_search` ]]
                then
                        echo "Matching files have been found under $PATH3"
                        cat /tmp/${PATTERN}_search
                        return 0
                else
                        echo "No file matches, please search elsewhere"
                        return 0
                fi
        fi
fi

exit 0

【问题讨论】：

标签： shell if-statement exit break

【解决方案1】：

我发现更好的方法是使用 while 循环遍历每个搜索。在每次迭代中，if-else 条件将测试是否找到匹配查找模式的文件。一旦这个条件为真，break 语句就能停止脚本。

下面的示例脚本：

#!/bin/sh

PATH1=/filer1_vol1_dir1
PATH2=/filer2_vol1_dir1
PATH3=/filer3_vol1_dir2
PATTERN=fruits

echo $PATH1 > /tmp/PATH.list
echo $PATH2 >> /tmp/PATH.list
echo $PATH3 >> /tmp/PATH.list
echo /tmp/PATH.list contains
cat /tmp/PATH.list
echo

cat /dev/null > /tmp/${PATTERN}_search.list

while read PATH
do

echo "Searching under the following parameters"
echo PATTERN = $PATTERN
echo PATH = $PATH
echo 
/usr/bin/find $PATH -type f -name "*$PATTERN*" -exec ls -l {} \; >> /tmp/${PATTERN}_search.list

/usr/bin/grep -i apples /tmp/${PATTERN}_search.list
if [ $? -eq 0 ]
then
    echo "All matching files have been found."
    break
else
    echo "No matches found, continuing search in next directory."
fi

done < /tmp/PATH.list

exit 0

【讨论】：