Regular and sed exercises

One 、 Regular

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

grep -i "^h" /etc/rc.d/rc.sysinit

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

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 -E "^# +[^[:space:]]+" /etc/fstab

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

grep "^to.*to$" /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 "\<[1-9]|1[0-9][0-9]|2[0-4][1-9]|25[0-5]\>"

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

grep -E "(Faild|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 ;

ll /etc | awk '{print $NF }'|grep -E "^(ns).*\.(conf)$"

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

grep -E "(.:+.)" /etc/passwd

Two 、sed

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/^ \+//' /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 -r 's/^# \+//' /etc/fstab

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

sed 's/^.*/#&/' /etc/fstab

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 's/ *inet//' | sed 's/ net.*//'

6、 Turn off the machine SELinux The function of

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

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

sed -i '1 i 192.168.198.1' /etc/hosts