在/etc/passwd文件中查找单词“linuxtechi”
root@Linux-world:~# grep linuxtechi /etc/passwd linuxtechi:x:1000:1000:linuxtechi,,,:/home/linuxtechi:/bin/bash root@Linux-world:~#
root@Linux-world:~# grep linuxtechi /etc/passwd /etc/shadow /etc/gshadow /etc/passwd:linuxtechi:x:1000:1000:linuxtechi,,,:/home/linuxtechi:/bin/bash /etc/shadow:linuxtechi:$6$DdgXjxlM$4flz4JRvefvKp0DG6re:16550:0:99999:7:::/etc/gshadow:adm:*::syslog,linuxtechi /etc/gshadow:cdrom:*::linuxtechi /etc/gshadow:sudo:*::linuxtechi /etc/gshadow:dip:*::linuxtechi /etc/gshadow:plugdev:*::linuxtechi /etc/gshadow:lpadmin:!::linuxtechi /etc/gshadow:linuxtechi:!:: /etc/gshadow:sambashare:!::linuxtechi root@Linux-world:~#
root@Linux-world:~# grep -l linuxtechi /etc/passwd /etc/shadow /etc/fstab /etc/mtab /etc/passwd /etc/shadow root@Linux-world:~#
root@Linux-world:~# grep -n linuxtechi /etc/passwd 39:linuxtechi:x:1000:1000:linuxtechi,,,:/home/linuxtechi:/bin/bash root@Linux-world:~#
输出/etc/passwd文件中所有不含单词“linuxtechi”的行
root@Linux-world:~# grep -v linuxtechi /etc/passwd
Bash脚本将 ^ 符号视作特殊字符,用于指定一行或者一个单词的开始。例如输出/etc/passes文件中所有以“root”开头的行
root@Linux-world:~# grep ^root /etc/passwd root:x:0:0:root:/root:/bin/bash root@Linux-world:~#
输出/etc/passwd文件中所有以“bash”结尾的行
root@Linux-world:~# grepbash$ /etc/passwd root:x:0:0:root:/root:/bin/bash linuxtechi:x:1000:1000:linuxtechi,,,:/home/linuxtechi:/bin/bash root@Linux-world:~#
Bash脚本将美元($)符号视作特殊字符,用于指定一行或者一个单词的结尾
root@Linux-world:~# grep -r linuxtechi /etc/ /etc/subuid:linuxtechi:100000:65536 /etc/group:adm:x:4:syslog,linuxtechi /etc/group:cdrom:x:24:linuxtechi /etc/group:sudo:x:27:linuxtechi /etc/group:dip:x:30:linuxtechi /etc/group:plugdev:x:46:linuxtechi /etc/group:lpadmin:x:115:linuxtechi /etc/group:linuxtechi:x:1000: /etc/group:sambashare:x:131:linuxtechi /etc/passwd-:linuxtechi:x:1000:1000:linuxtechi,,,:/home/linuxtechi:/bin/bash /etc/passwd:linuxtechi:x:1000:1000:linuxtechi,,,:/home/linuxtechi:/bin/bash ............................................................................
上面的命令将会递归的在/etc目录中查找“linuxtechi”单词
root@Linux-world:~# grep ^$ /etc/shadow root@Linux-world:~#
由于/etc/shadow文件中没有空行,所以没有任何输出
grep命令的-i参数在查找时忽略字符的大小写。我们来看一个例子,在paswd文件中查找“LinuxTechi”单词
nextstep4it@localhost:~$ grep -i LinuxTechi /etc/passwd linuxtechi:x:1001:1001::/home/linuxtechi:/bin/bash nextstep4it@localhost:~$
例如,我想在一条grep命令中查找‘linuxtechi’和‘root’单词,使用-e参数,我们可以查找多个模式
root@Linux-world:~# grep -e "linuxtechi" -e "root" /etc/passwd root:x:0:0:root:/root:/bin/bash linuxtechi:x:1000:1000:linuxtechi,,,:/home/linuxtechi:/bin/bash root@Linux-world:~#
首先,在当前目录中创建一个搜索模式文件“grep_pattern”,我想文件中输入的如下内容
root@Linux-world:~# cat grep_pattern ^linuxtechi root false$ root@Linux-world:~#
现在,试试使用grep_pattern文件进行搜索
root@Linux-world:~# grep -f grep_pattern /etc/passwd
继续上面例子,我们在grep命令中使用-c命令计算匹配指定模式的数量
root@Linux-world:~# grep -c -f grep_pattern /etc/passwd 22 root@Linux-world:~#
a)使用-B参数输出匹配行的前4行
root@Linux-world:~# grep -B 4"games" /etc/passwd
b)使用-A参数输出匹配行的后4行
root@Linux-world:~# grep -A 4"games" /etc/passwd
c)使用-C参数输出匹配行的前后各4行
root@Linux-world:~# grep -C 4"games" /etc/passwd