使用grep实现精确过滤的五种方法（1）当被过滤的内容占据一行时[root@MySQL scripts]# cat oldboy.log 20002002000[root@MySQL scripts]# grep "\b200\b" oldboy.log 200 #<==正则按单词匹配[root@MySQL scripts]# grep -w "200" oldboy.log 200 #<==按单词匹配[root@MySQL scripts]# grep -x "200" oldboy.log 200 #<==按整行匹配[root@MySQL scripts]# grep "^200$" oldboy.log 200 #<==正则开头结尾匹配，相当于整行匹配[root@MySQL scripts]# grep -E "\<200\>" oldboy.log 200 #<==扩展正则（2）当被过滤的内容占据一行的一部分[root@MySQL scripts]# cat oldboy.log 200 oldboy0200 oldgirl2000 littleboy[root@MySQL scripts]# grep "\b200\b" oldboy.log200 oldboy[root@MySQL scripts]# grep -w "200" oldboy.log200 oldboy[root@MySQL scripts]# grep -x "200" oldboy.log#<==按整行匹配，所以没结果[root@MySQL scripts]# grep -x "200 oldboy" oldboy.log200 oldboy[root@MySQL scripts]# grep "^200$" oldboy.log#<==按整行匹配，所以没结果[root@MySQL scripts]# grep "^200 oldboy$" oldboy.log200 oldboy[root@MySQL scripts]# grep -E "\<200\>" oldboy.log 200 oldboy原文：http://www.cnblogs.com/howhy/p/6275484.html