/etc/profile与/etc/rc.local的区别

一、/etc/profile 环境变量

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。

二、/etc/rc.local 开机自启动

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。