[root@localhost ~]# cat /etc/passwd |grep root    #匹配任意位置的root
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
[root@localhost ~]# cat /etc/passwd |grep ^root    #匹配root出现在文本一行的开头
root:x:0:0:root:/root:/bin/bash
[root@localhost ~]# cat /etc/passwd |grep root$  #匹配root出现在文本一行的结尾
[root@localhost ~]# cat /etc/passwd |grep ^root$  #匹配文本的一行刚刚好只有root

[root@localhost ~]# cat /etc/passwd |grep [Rr]oot    #匹配文本任意位居中，含有Root或者root
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin

 

正则表达式--grep_数据

 

grep 同时去掉注释符和空行，并且使用echo显示颜色字体

[root@localhost ~]# cat /etc/ssh/sshd_config | grep -v ^# |grep -v ^$
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key
SyslogFacility AUTHPRIV
AuthorizedKeysFile .ssh/authorized_keys
PasswordAuthentication yes
ChallengeResponseAuthentication no
GSSAPIAuthentication yes
GSSAPICleanupCredentials no
UsePAM yes
X11Forwarding yes
AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE
AcceptEnv XMODIFIERS
Subsystem sftp /usr/libexec/openssh/sftp-server

[root@localhost ~]# echo -e "\e[1;31m `cat /etc/ssh/sshd_config | grep -v ^# |grep -v ^$` \e[0m"
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key
SyslogFacility AUTHPRIV
AuthorizedKeysFile .ssh/authorized_keys
PasswordAuthentication yes
ChallengeResponseAuthentication no
GSSAPIAuthentication yes
GSSAPICleanupCredentials no
UsePAM yes
X11Forwarding yes
AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE
AcceptEnv XMODIFIERS
Subsystem sftp /usr/libexec/openssh/sftp-server
[root@localhost ~]#

正则表达式--grep_bash_02