简介
Linux 中可以使用分号";“、双and号”&&“和双竖线”||"来连接多个命令。根据场景的不同适当的使用合适的符号。
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 " ?”来判断命令是否正确执行，如果"?”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
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# -*- coding: utf-8 -*-# time: 2022/10/4 21:47# file: cmd_1_success.py# 公众号: 玩转测试开发def run_success_1(): print("cmd_1 start run") print("cmd_1 do something") print("cmd_1 end")if __name__ == '__main__': run_success_1() |
cmd1_fail = python cmd_1_fail.py
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# -*- coding: utf-8 -*-# time: 2022/10/4 21:47# file: cmd_1_fail.py# 公众号: 玩转测试开发def run_fail_1(): print("cmd_1 start run") raise BaseException print("cmd_1 end")if __name__ == '__main__': run_fail_1() |
cmd2_success = python cmd_2_success.py
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# -*- coding: utf-8 -*-# time: 2022/10/4 21:49# file: cmd_2_success.pydef run_success_2(): print("cmd_2 start run") print("cmd_2 do something") print("cmd_2 end")if __name__ == '__main__': run_success_2() |
cmd2_fail = python cmd_2_fail.py
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# -*- coding: utf-8 -*-# time: 2022/10/4 21:51# file: cmd_2_fail.py# 公众号: 玩转测试开发def run_fail_2(): print("cmd_2 start run") raise BaseException print("cmd_2 end")if __name__ == '__main__': run_fail_2() |
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
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#bin/bashpython cmd_1_success; python cmd_2_successpython cmd_1_success && python cmd_2_successpython cmd_1_success || python cmd_2_success |
演示分号的四类基础情况：
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# 第一种情况：cmd_1_success; cmd_2_successcmd_1 start runcmd_1 do somethingcmd_1 endcmd_2 start runcmd_2 do somethingcmd_2 end# 第二种情况：cmd_1_fail; cmd_2_successcmd_1 start runTraceback (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 BaseExceptionBaseExceptioncmd_2 start runcmd_2 do somethingcmd_2 end# 第三种情况：cmd_1_success; cmd_2_failcmd_1 start runcmd_1 do somethingcmd_1 endcmd_2 start runTraceback (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 BaseExceptionBaseException# 第四种情况：cmd_1_fail; cmd_2_failcmd_1 start runTraceback (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 BaseExceptionBaseExceptioncmd_2 start runTraceback (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 BaseExceptionBaseException |
演示 && 的四类基本情况：
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# 第一种情况：cmd_1_success && cmd_2_successcmd_1 start runcmd_1 do somethingcmd_1 endcmd_2 start runcmd_2 do somethingcmd_2 end# 第二种情况：cmd_1_fail && cmd_2_successcmd_1 start runTraceback (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 BaseExceptionBaseException# 第三种情况：cmd_1_success && cmd_2_failcmd_1 start runcmd_1 do somethingcmd_1 endcmd_2 start runTraceback (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 BaseExceptionBaseException# 第四种情况：cmd_1_fail && cmd_2_failcmd_1 start runTraceback (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 BaseExceptionBaseException |
演示 || 的四类基本情况：
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# 第一种情况：cmd_1_success || cmd_2_successcmd_1 start runcmd_1 do somethingcmd_1 end# 第二种情况：cmd_1_fail || cmd_2_successcmd_1 start runTraceback (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 BaseExceptionBaseExceptioncmd_2 start runcmd_2 do somethingcmd_2 end# 第三种情况：cmd_1_success || cmd_2_failcmd_1 start runcmd_1 do somethingcmd_1 end# 第四种情况：cmd_1_fail || cmd_2_failcmd_1 start runTraceback (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 BaseExceptionBaseExceptioncmd_2 start runTraceback (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 BaseExceptionBaseException |
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。
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原文链接：https://blog.csdn.net/hzblucky1314/article/details/127334355
