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目录
- 简介
- 一、分号
- 二、&&
- 三、||
- 案例剖析
简介
在Linux中，可以使用分号";"、双AND号"&&"和双竖线"||"来连接多个命令。根据不同场景，选择合适的符号使用。
历史攻略
Python：执行DOS命令、Linux命令
命令连接符解析：
仅连接，表示运行先后，无逻辑关系：分号";"，如command1 ; command2
逻辑与关系：&&，如command1 && command2
逻辑或关系：||，如command1 || command2
一、分号
命令之间没有逻辑关系。分号连接的命令会按照顺序从前向后依次执行，但分号两端的命令之间没有任何逻辑关系，所有写出来的命令最终都会被执行，即使分号前面的命令出错也不影响后面的命令。
二、&&
逻辑与。&&连接的命令会按照顺序从前向后执行，但只有当command1正确执行才执行command2，如果command1不正确执行，则不执行command2。在bash中，通过预定义变量"?"来判断命令是否正确执行，如果"?"的值为0则表示前一条命令正确执行，其他任意值都表示不正确执行。
三、||
逻辑或。||连接的命令会按照顺序从前向后执行，但只有当command1不正确执行才执行command2，command1正确执行则不会执行command2。||和&&都是短路符号，符号左右的命令之间具有逻辑关系。
案例剖析
<code># -*- coding: utf-8 -*-
# time: 2022/10/4 21:47
# file: cmd_1_success.py
# 公众号: 玩转测试开发
<p>def run_success_1():
print("cmd_1 start run")
print("cmd_1 do something")
print("cmd_1 end")</p><p>if <strong>name</strong> == '<strong>main</strong>':
run_success_1()
</code>cmd1_fail = python cmd_1_fail.py
<code># -<em>- coding: utf-8 -</em>-</p><h1>time: 2022/10/4 21:47</h1><h1>file: cmd_1_fail.py</h1><h1>公众号: 玩转测试开发</h1><p>def run_fail_1():
print("cmd_1 start run")
raise BaseException
print("cmd_1 end")</p><p>if <strong>name</strong> == '<strong>main</strong>':
run_fail_1()
</code>cmd2_success = python cmd_2_success.py
<code># -<em>- coding: utf-8 -</em>-</p><h1>time: 2022/10/4 21:49</h1><h1>file: cmd_2_success.py</h1><p>def run_success_2():
print("cmd_2 start run")
print("cmd_2 do something")
print("cmd_2 end")</p><p>if <strong>name</strong> == '<strong>main</strong>':
run_success_2()
</code>cmd2_fail = python cmd_2_fail.py
<code># -<em>- coding: utf-8 -</em>-</p><h1>time: 2022/10/4 21:51</h1><h1>file: cmd_2_fail.py</h1><h1>公众号: 玩转测试开发</h1><p>def run_fail_2():
print("cmd_2 start run")
raise BaseException
print("cmd_2 end")</p><p>if <strong>name</strong> == '<strong>main</strong>':
run_fail_2()
</code>即：存在4种基本情况
cmd_1_success、cmd_2_success
cmd_1_fail、cmd_2_success
cmd_1_success、cmd_2_fail
cmd_1_fail、cmd_2_fail
test.sh
<code>#bin/bash python cmd_1_success; python cmd_2_success python cmd_1_success && python cmd_2_success python cmd_1_success || python cmd_2_success </code>
演示分号的四类基础情况：
<code># 第一种情况：cmd_1_success; cmd_2_success cmd_1 start run cmd_1 do something cmd_1 end cmd_2 start run cmd_2 do something cmd_2 end</p><h1>第二种情况：cmd_1_fail; cmd_2_success</h1><p>cmd_1 start run Traceback (most recent call last): File "cmd_1_fail.py", line 14, in <module> run_fail_1() File "cmd_1_fail.py", line 9, in run_fail_1 raise BaseException BaseException cmd_2 start run cmd_2 do something cmd_2 end</p><h1>第三种情况：cmd_1_success; cmd_2_fail</h1><p>cmd_1 start run cmd_1 do something cmd_1 end cmd_2 start run Traceback (most recent call last): File "cmd_2_fail.py", line 14, in <module> run_fail_2() File "cmd_2_fail.py", line 9, in run_fail_2 raise BaseException BaseException</p><h1>第四种情况：cmd_1_fail; cmd_2_fail</h1><p>cmd_1 start run Traceback (most recent call last): File "cmd_1_fail.py", line 14, in <module> run_fail_1() File "cmd_1_fail.py", line 9, in run_fail_1 raise BaseException BaseException cmd_2 start run Traceback (most recent call last): File "cmd_2_fail.py", line 14, in <module> run_fail_2() File "cmd_2_fail.py", line 9, in run_fail_2 raise BaseException BaseException </module></module></module></module></code>
演示 && 的四类基本情况：
<code># 第一种情况：cmd_1_success && cmd_2_success cmd_1 start run cmd_1 do something cmd_1 end cmd_2 start run cmd_2 do something cmd_2 end</p><h1>第二种情况：cmd_1_fail && cmd_2_success</h1><p>cmd_1 start run Traceback (most recent call last): File "cmd_1_fail.py", line 14, in <module> run_fail_1() File "cmd_1_fail.py", line 9, in run_fail_1 raise BaseException BaseException</p><h1>第三种情况：cmd_1_success && cmd_2_fail</h1><p>cmd_1 start run cmd_1 do something cmd_1 end cmd_2 start run Traceback (most recent call last): File "cmd_2_fail.py", line 14, in <module> run_fail_2() File "cmd_2_fail.py", line 9, in run_fail_2 raise BaseException BaseException</p><h1>第四种情况：cmd_1_fail && cmd_2_fail</h1><p>cmd_1 start run Traceback (most recent call last): File "cmd_1_fail.py", line 14, in <module> run_fail_1() File "cmd_1_fail.py", line 9, in run_fail_1 raise BaseException BaseException </module></module></module></module></code>
演示 || 的四类基本情况：
<code># 第一种情况：cmd_1_success || cmd_2_success cmd_1 start run cmd_1 do something cmd_1 end</p><h1>第二种情况：cmd_1_fail || cmd_2_success</h1><p>cmd_1 start run Traceback (most recent call last): File "cmd_1_fail.py", line 14, in <module> run_fail_1() File "cmd_1_fail.py", line 9, in run_fail_1 raise BaseException BaseException cmd_2 start run cmd_2 do something cmd_2 end</p><h1>第三种情况：cmd_1_success || cmd_2_fail</h1><p>cmd_1 start run cmd_1 do something cmd_1 end</p><h1>第四种情况：cmd_1_fail || cmd_2_fail</h1><p>cmd_1 start run Traceback (most recent call last): File "cmd_1_fail.py", line 14, in <module> run_fail_1() File "cmd_1_fail.py", line 9, in run_fail_1 raise BaseException BaseException cmd_2 start run Traceback (most recent call last): File "cmd_2_fail.py", line 14, in <module> run_fail_2() File "cmd_2_fail.py", line 9, in run_fail_2 raise BaseException BaseException </module></module></module></module></code>
即：分号前后运行无逻辑关系；&&后面的命令需要前面的命令正常执行；
||后面的命令需要前面的命令运行失败才执行。
至此，本文关于Linux Shell脚本多命令执行逻辑的示例详解已介绍完毕。更多相关Shell脚本多命令执行逻辑的内容，请搜索我们之前的文章或继续浏览下面的相关文章，希望大家以后多多支持我们！
