Question

这是我的文件

$ cat delete1
KEEPALIVED-MIB.txt:     virtualServerRateCps Gauge32,
KEEPALIVED-MIB.txt:    SYNTAX INTEGER { tcp(1), udp(2) }
KEEPALIVED-MIB.txt:virtualServerRateCps OBJECT-TYPE
KEEPALIVED-MIB.txt:     realServerRateCps Gauge32,
KEEPALIVED-MIB.txt:realServerRateCps OBJECT-TYPE
KEEPALIVED-MIB.txt:     virtualServerRateCps,
KEEPALIVED-MIB.txt:     realServerRateCps,
MF-Diameter-MIB.txt:                tcp(1),

如果我搜索'cpu'，则找不到符合我期望的任何匹配项。

$ grep -i 'cpu' delete1

但是，如果我添加通配符'cpu*'，则会找到匹配项。但是我不确定为什么吗？ 有人可以告诉我为什么我在这里找到比赛吗？

$ grep -i 'cpu*' delete1
KEEPALIVED-MIB.txt:     virtualServerRateCps Gauge32,
KEEPALIVED-MIB.txt:    SYNTAX INTEGER { tcp(1), udp(2) }
KEEPALIVED-MIB.txt:virtualServerRateCps OBJECT-TYPE
KEEPALIVED-MIB.txt:     realServerRateCps Gauge32,
KEEPALIVED-MIB.txt:realServerRateCps OBJECT-TYPE
KEEPALIVED-MIB.txt:     virtualServerRateCps,
KEEPALIVED-MIB.txt:     realServerRateCps,
MF-Diameter-MIB.txt:                tcp(1),

我已经读过一些docs，我在想它是否找不到cpu，不确定是否可以找到cpu或cpuuuuuu

a*  ---> a{0,}  ---> Match a or aa or aaaaa or an empty string

Answer 1

我认为这可以解释。

$ cat delete
cpu1
cpu2
cpu
cp

$ grep -i 'cpu' delete
cpu1
cpu2
cpu

这正在寻找cpu或cpuuuu或cp

$ grep -i 'cpu*' delete
cpu1
cpu2
cpu
cp

了解带有*的基本正则表达式和grep组合

1 个答案: