1、 Show /etc/rc.d/rc.sysinit File with size insensitive h Beginning line ;

[[email protected] shell]# grep '^[hH]' /etc/passwd

2、 Show /etc/passwd China and Israel sh The line at the end

[[email protected] shell]# grep 'sh$' /etc/passwd

3、 Show /etc/fstab China and Israel # start , One or more whitespace characters followed by , And then it's followed by any non whitespace line ;

grep '^\#[[:space:]]\{1,\}.\{1,\}' /etc/fastab

4. lookup /etc/rc.d/rc.local Contained in the “ With to Start with to ending ” Word serial of

grep -Ew "(to).*\1" /etc/rc.d/rc.local

5. lookup /etc/inittab contains “ With s start , And d Ending words ” Pattern line

grep -w '\<s[a-z]*d\>' /etc/inittab 

6. lookup ifconfig In the command result 1-255 Integer between

ifconfig | grep -oE "<\[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]\>"

7、 Show /var/log/secure The file contains “Failed” or “FAILED” The line of ;

grep -w 'Failed|FAILED' /var/log/secure

8、 stay /etc/passwd Take out the default shell by bash The line of

grep "bash" /etc/passwd

9、 List... In long format /etc/ Directory to ns start 、.conf File information at the end

10、 Highlight passwd Colon in file , And the characters on both sides ;

grep --color ".:." /etc/passwd

8

1、 Delete /etc/grub2.conf All the white space characters at the beginning of the line that start with white space in the file

sed 's/^[[:space:]]//' /etc/grub2.cfg

2、 Delete /etc/fstab All # start , The first line of a line followed by at least one white space character # And white space characters

 sed   's/^#[[:space:]]*//' /etc/fstab

3、 stay /root/install.log Add... At the beginning of each line # Number

sed 's/^.*$/#&/' /root/install.log

4、 stay /etc/fstab The document does not contain # The beginning of the first line increases # Number

 sed 's/^[^#]/#&/' /etc/fstab

5、 utilize sed Take out ifconfig In the command IPv4 Address

ifconfig |sed -n '2p' | sed -r "s/.*inet[[:space:]]*//" | sed -r "s/[[:space:]]*netmask.*//"

6、 Turn off the machine SELinux The function of

sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config

7、 stay /etc/hosts Add content to the configuration file

sed -i '$a bye' test     # In the file test1 Enter directly in the last line of "bye"
sed -i '1i\a' test     # In the file test1 Insert a line before the first line in "aaa"