/etc/profile与/etc/rc.local的区别
用户登录的时候执行sh脚本的顺序，每次登录的时候都会完全执行的
/etc/profile.d/file /etc/profile /etc/bashrc /root/.bashrc /root/.bash_profile
用户脚本，在用户登陆后执行，只有用户权限，所以只能执行用户权限下的程序，不登录就不会执行。
系统脚本，系统启动后自动执行，与是否登陆无关，所以优先级高于profile，可以指定执行程序的权限
以下是 在/etc/rc.loacl 配置的开机启动elk系列应用
[root@test-2-45 /]# more /etc/rc.local #!/bin/bash # THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES # # It is highly advisable to create own systemd services or udev rules # to run scripts during boot instead of using this file. # # In contrast to previous versions due to parallel execution during boot # this script will NOT be run after all other services. # # Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure # that this script will be executed during boot. #启动elk系统应用 /home/elasticsearch/es_node/bin/elasticsearch.sh start sleep 10s /home/elasticsearch/es_date/bin/elasticsearch.sh start sleep 10s /usr/local/zookeeper/bin/zkServer.sh start sleep 10s /home/elasticsearch/kafka/kafka start sleep 10s /home/elasticsearch/logstash_kafka/logstash_kafka start sleep 10s /home/elasticsearch/filebeat/filebeat start sleep 10s /home/elasticsearch/kibana/kibana start sleep 10s touch /var/lock/subsys/local
设置环境变量的脚本，可以放在profile.d目录下面，但开机执行任务不应该放在profile.d目录下，因为每次登陆都会执行profile.d目录下的文件，会导致重复执行，
设置开机启动任务，应该放在rc.local中执行，它只会在系统启动时执行一次。