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Linux——xargs命令学习

时间:2019-10-17 11:58:56      阅读:55      评论:0      收藏:0      [点我收藏+]

有时候我们会遇到需要将指定命令返回结果进行处理的情况

这种情况下,可能就需要写for循环之类的脚本进行处理了(目前我只能想到这种方法)

但是想起来还有一个xargs命令,组合这个命令就比较省事了。

场景如下:

安装Redis执行make test时,报Redis已在运行导致冲突。ps -ef查看Redis,发现还真的有十来个redis进程再跑。那就只能把其全部关闭了。一个一个kill不现实,于是研究了一下xargs命令来实现。以下是我的做法

1.首先我们需要获取到所有redis进程信息

ps -ef|grep redis |grep -v grep>/root/redispid.txt

[root@bogon ~]# cat redispid.txt 
root      69984      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21242
root      69992      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21272
root      69994      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21222
root      69998      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21302
root      70001      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21262
root      70006      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21252
root      70009      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21322
root      70013      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21342
root      70015      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21282
root      70016      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21352
root      70017      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21292
root      70030      1  0 23:09 pts/1    00:00:00 src/redis-server 127.0.0.1:21312
root      70875      1  0 23:10 pts/1    00:00:01 src/redis-server 127.0.0.1:21325
root      70877      1  0 23:10 pts/1    00:00:01 src/redis-server 127.0.0.1:21355
root      70894      1  0 23:10 pts/1    00:00:01 src/redis-server 127.0.0.1:21315
root      70900      1  0 23:10 pts/1    00:00:01 src/redis-server 127.0.0.1:21215
root      70954      1  0 23:10 pts/1    00:00:00 src/redis-server 127.0.0.1:21235
root      71190      1  0 23:10 pts/1    00:00:00 src/redis-server 127.0.0.1:21357
root      71211      1  0 23:10 pts/1    00:00:00 src/redis-server 127.0.0.1:21297
root      71221      1  0 23:10 pts/1    00:00:00 src/redis-server 127.0.0.1:21246
root      71448      1  0 23:10 pts/1    00:00:00 src/redis-server 127.0.0.1:21238
root      71468      1  0 23:10 pts/1    00:00:00 src/redis-server 127.0.0.1:21359
root      71843      1  0 23:11 pts/1    00:00:00 src/redis-server 127.0.0.1:21275
root      71928      1  0 23:11 pts/1    00:00:01 src/redis-server 127.0.0.1:21229
root      73476      1  0 23:18 pts/1    00:00:00 src/redis-server 127.0.0.1:21365

2.获取pid列

[root@bogon ~]# awk {print $2} redispid.txt 
69984
69992
69994
69998
70001
70006
70009
70013
70015
70016
70017
70030
70875
70877
70894
70900
70954
71190
71211
71221
71448
71468
71843
71928
73476

3.执行kill动作。可以看到,直接kill掉了

[root@bogon ~]# awk {print $2} redispid.txt |xargs kill -9 
[root@bogon ~]# ps -ef|grep redis
root      73607  33777  0 23:27 pts/3    00:00:00 grep --color=auto redis
[root@bogon ~]# netstat -tlnp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/systemd           
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1003/sshd           
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      34671/master        
tcp        0      0 0.0.0.0:10051           0.0.0.0:*               LISTEN      53270/zabbix_server 
tcp6       0      0 :::3306                 :::*                    LISTEN      53233/mysqld        
tcp6       0      0 :::111                  :::*                    LISTEN      1/systemd           
tcp6       0      0 :::80                   :::*                    LISTEN      54805/docker-proxy  
tcp6       0      0 :::22                   :::*                    LISTEN      1003/sshd           
tcp6       0      0 ::1:25                  :::*                    LISTEN      34671/master        
tcp6       0      0 :::10051                :::*                    LISTEN      53270/zabbix_server 
[root@bogon ~]# 

4.简单解释一下xargs命令

格式如下:command |xargs command    第一个command是正常命令,获取到管道后需要用到的命令参数,第二个command是个不完成的命令,第二个命令的参数是第一个命令返回的结果。而xargs则是把管道前的参数传到管道后,同时把参数里包含的换行和空白全部替换为空格。所以才会出现文本里的多行pid被顺利kill掉。整个命令就相当于kill -9 69984 69992 69994 69998 70001 70006 70009 70013 70015 70016 70017 70030 70875 70877 70894 70900 70954 71190 71211 71221 71448 71468 71843 71928 73476

 

Linux——xargs命令学习

原文:https://www.cnblogs.com/biaopei/p/11691169.html

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