如果采用RPM包安装，安装路径应在 /etc/httpd目录下。
(学习教程推荐：apache)
apache配置文件：/etc/httpd/conf/httpd.conf 可以修改相关的访问路径及配置
Apache模块路径：/usr/sbin/apachectl 启动模块
web目录：/var/www/html 项目的存储路径
如果采用源代码安装，一般默认安装在/usr/local/apache2目录下。
启动apache报错信息，很大程度需要检查是不是端口被占用了，因为默认apache启动的是80端口。像nginx默认页是开启80端口。
报错信息如下：[root@localhost ~]# service httpd restart
Redirecting to /bin/systemctl restart httpd.service
Job for httpd.service failed because the control process exited with error code. See "systemctl status httpd.service" and "journalctl -xe" for details.
[root@localhost ~]# service httpd status
Redirecting to /bin/systemctl status httpd.service
● httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled)
Active: failed (Result: exit-code) since 三 2018-12-05 14:42:42 CST; 11s ago
Docs: man:httpd(8)
man:apachectl(8)
Process: 3640 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=1/FAILURE)
Process: 3639 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE)
Main PID: 3639 (code=exited, status=1/FAILURE)
12月 05 14:42:42 localhost.localdomain httpd[3639]: (98)Address already in use: AH00072: make_sock: could not bind to address [::]:80
12月 05 14:42:42 localhost.localdomain httpd[3639]: (98)Address already in use: AH00072: make_sock: could not bind to address 0.0.0.0:80
12月 05 14:42:42 localhost.localdomain httpd[3639]: no listening sockets available, shutting down
12月 05 14:42:42 localhost.localdomain httpd[3639]: AH00015: Unable to open logs
12月 05 14:42:42 localhost.localdomain systemd[1]: httpd.service: main process exited, code=exited, status=1/FAILURE
12月 05 14:42:42 localhost.localdomain kill[3640]: kill: cannot find process ""
12月 05 14:42:42 localhost.localdomain systemd[1]: httpd.service: control process exited, code=exited status=1
12月 05 14:42:42 localhost.localdomain systemd[1]: Failed to start The Apache HTTP Server.
12月 05 14:42:42 localhost.localdomain systemd[1]: Unit httpd.service entered failed state.
12月 05 14:42:42 localhost.localdomain systemd[1]: httpd.service failed.
[root@localhost ~]#
可以看到Address already in use错误，修改apache的端口。
编辑/etc/httpd/conf/httpd.conf
再次重启即可。
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