1. 查找单个关键字
举例：查找Baiduspider访问日志，并输出行号。
# grep -n Baiduspider /usr/local/nginx1.14/logs/access.log
3371:180.76.15.137 - - [31/Dec/2018:05:05:46 +0800] "GET /asset/detail/show/RG9ja2VyIENFIDE4LjA5IOS9v+eUqERvY2tlcmZpbGXlronoo4 HTTP/1.1" 200 4748 "-" "Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)"
4570:180.76.15.11 - - [08/Jan/2019:16:57:04 +0800] "GET /asset/detail/show/RG9ja2VyIENFIDE4LjA5IOS9v+eUqERvY2tlcmZpbGXlronoo4 HTTP/1.1" 200 7754 "-" "Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)"
4693:180.76.15.20 - - [09/Jan/2019:05:29:54 +0800] "GET /asset/detail/show/Q2VudE9TNy41IE15U1FMOC4wLjEzIFJQTea6kOeggee8luivke HTTP/1.1" 200 16691 "-" "Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)"
4924:180.76.15.160 - - [10/Jan/2019:22:30:28 +0800] "GET /asset/detail/show/SlF1ZXJ5My4zLjEg6YCJ5oup5Zmo HTTP/1.1" 200 10049 "-" "Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)"
...
2. 查找多个关键字
举例：查找Baiduspider、bingbot、Googlebot访问日志，并输出行号。
# grep -n -E 'Baiduspider|bingbot|Googlebot' /usr/local/nginx1.14/logs/access.log
5620:203.208.60.0 - - [14/Jan/2019:10:26:09 +0800] "GET / HTTP/1.1" 200 17232 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"
5639:180.76.15.21 - - [14/Jan/2019:16:39:35 +0800] "GET / HTTP/1.1" 200 17232 "-" "Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)"
5888:157.55.39.40 - - [17/Jan/2019:13:45:05 +0800] "GET / HTTP/1.1" 200 17232 "-" "Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)"
...
3. 多文件查找关键字
举例：查找10.100.78.12服务器多天的监控日志。
# grep 10.100.78.12 2018-12-10.bjyz.network.monitor.log 2018-12-11.bjyz.network.monitor.log
2018-12-10.bjyz.network.monitor.log:[2018-12-10]|[13:10:00]|10.100.78.12|active
2018-12-11.bjyz.network.monitor.log:[2018-12-11]|[13:10:00]|10.100.78.12|down
4. 递归查找关键字
举例：递归查找10.100.78.12服务器多天的监控日志。
grep -r 10.100.78.12
2018-12-10.bjyz.network.monitor.log:[2018-12-10]|[13:10:00]|10.100.78.12|active
2018-12-11.bjyz.network.monitor.log:[2018-12-11]|[13:10:00]|10.100.78.12|down
2018-12-12.bjyz.network.monitor.log:[2018-12-12]|[13:10:00]|10.100.78.12|active
5. 查找指定进程
举例：查找java进程。
# ps -ef | grep java
6. 查找进程个数
举例：查找java进程个数。
# ps -ef | grep -c java