1.Journalctl查看並操作Systemd日誌
- 被隱藏的部分日誌可以通過左右箭頭按鍵查看， 如果不想分頁輸出，那麼可以使用 --no-pager 選項
-
常用選項
journalctl -a 顯示全部信息，無論其是否包含不可輸出的字符
journalctl -b本次啓動後的所有日誌
journalctl -b -1查看上次啓動後的日誌（需要在配置文件啓用持久記錄）
journalctl -u 查看指定服務日誌信息(systemd的單元)
journalctl --since和--until查看指定時間的日誌
journalctl -f動態顯示日誌
journalctl -p按日誌警告級別查看示例：
journalctl --since "2017-01-10" --until "2017-01-11 03:00"
journalctl --since "20 min ago"
journalctl -u httpd.service --since today
journalctl -p err -b - 修改成持久記錄
vim /etc/systemd/journald.conf . . . [Journal] Storage=persistent - 日誌警告級別
0: emerg
1: alert
2: crit
3: err
4: warning
5: notice
6: info
7: debug
2. 在centos7中手動設置Nginx開機啓動
1.網上下載nginx安裝包並解壓
tar xvf nginx-1.14.2.tar.gz
2.編譯nginx
./configure --prefix=/data/nginx1.4
3.安裝nginx
make -j 4 && make install
4.啓動測試nginx
[root@centos7 ~]#/data/nginx1.4/sbin/nginx -h
nginx version: nginx/1.14.2
Usage: nginx [-?hvVtTq] [-s signal] [-c filename] [-p prefix] [-g directives]
Options:
-?,-h : this help
-v : show version and exit
-V : show version and configure options then exit
-t : test configuration and exit
-T : test configuration, dump it and exit
-q : suppress non-error messages during configuration testing
-s signal : send signal to a master process: stop, quit, reopen, reload
-p prefix : set prefix path (default: /data/nginx1.4/)
-c filename : set configuration file (default: conf/nginx.conf)
-g directives : set global directives out of configuration file/data/nginx1.4/sbin/nginx
[root@centos7 nginx-1.14.2]#curl localhost
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>5.在/etc/systemd/system文件夾新建service文件讓systemd管理
[root@centos7 ~]#vim nginx.service
[Unit]
Description=nginx
After=network.target
[Service]
Type=forking
ExecStart=/data/nginx1.4/sbin/nginx
ExecReload=/data/nginx1.4/sbin/nginx -s reload
ExecStop=/data/nginx1.4/sbin/nginx -s quit
PrivateTmp=true
[Install]
WantedBy=multi-user.target如果不是默認配置文件路徑，在service中加入EnvironmentFile 路徑
如：EnvironmentFile=/data/nginx1.4/conf/nginx.conf
6.讓systemd加載該servicesystemctl daemon-reload
7.設置開機啓動
[root@centos7 system]#systemctl enable nginx.service
Created symlink from /etc/systemd/system/multi-user.target.wants/nginx.service to /etc/systemd/system/nginx.service.8.重啓系統測試
[root@centos7 ~]#systemctl status nginx.service
● nginx.service - nginx
Loaded: loaded (/etc/systemd/system/nginx.service; enabled; vendor preset: disabled)
Active: active (running) since Thu 2019-01-03 19:34:00 CST; 50s ago
Process: 960 ExecStart=/data/nginx1.4/sbin/nginx (code=exited, status=0/SUCCESS)
Main PID: 973 (nginx)
CGroup: /system.slice/nginx.service
├─973 nginx: master process /data/nginx1.4/sbin/nginx
└─975 nginx: worker process
Jan 03 19:34:00 centos7.dcrfan systemd[1]: Starting nginx...
Jan 03 19:34:00 centos7.dcrfan systemd[1]: Started nginx.3. SIGHUP、SIGQUIT、 SIGTERM、 SIGINT區別
1) SIGHUP: 無須關閉進程而讓其重讀配置文件
2) SIGINT: 中止正在運行的進程；相當於Ctrl+c ，用於通知前臺進程組終止進程
3) SIGQUIT:相當於ctrl+\ ，進程在因收到SIGQUIT退出時會產生core文件, 在這個意義上類似於一個程序錯誤信號。
15) SIGTERM：終止正在運行的進程 ，通常用來要求程序自己正常退出，shell命令kill缺省產生這個信號。如果進程終止不了，我們纔會嘗試SIGKILL（9）。
4.利用awk實現tcp連接中處於listen個數統計
[root@centos7 ~]#ss -tan|awk '/^LISTEN/{state[$1]++}END{for (i in state) {print i,state[i]}}'
LISTEN 12或者
[root@centos7 ~]#netstat -tan | awk '$NF=="LISTEN"{state[$NF]++}END{for (i in state) {print i,state[i]}}'
LISTEN 12