[Small exercise] grep exercise

Exercise:
1. display the lines starting with "S" of the/proc/meminfo file with no size difference;
Grep-I s/proc/meninfo
2. display the rows ending with nologin in/etc/passwd;
Grep nologin $/etc/passwd
3. the/etc/inittab starts with #, followed by one or more blank characters, and followed by any character rows;
Grep -- color ^ #. */etc/inittab
4. the/etc/inittab displays the rows of a number (that is, a number between two colons;
Grep: [0-9]:/etc/inittab
5. display the lines starting with one or more blank characters in the/boot/GRUB/grub. conf file;
Grep ^ [[: Space:] \ {1, \}. * "/boot/GRUB/grub. conf
Grep-e -- color "^ [: Space:] {1,}. *"/boot/GRUB/grub. conf
6. display the rows starting with a number in the/etc/inittab file and ending with the same number as the starting number;
Grep "^ \ ([0-9] \). * \ 1 $"/etc/inittab
7. The ifconfig command can display information related to the IP address of the current host. If you use the grep or other text processing commands to retrieve the IP addresses of the local host, the requirements do not include 127.0.0.1;
Ifcofig | grep "Inet ADDR" | grep-V '2017. 0.0.1 '| cut-D:-F2 | cut-d "" F1
8. The/etc/sysconfig/network-scripts/ifcfg-eth0 file contains a line similar to an IP address point in decimal format;
Grep-e "([0-9] {1, 3} \.) {3} \. [0-9] {1, 3}"/etc/sysconfig/network-scripts/ifcfg-eth0
Grep "[0-9] \ {1, 3 \}\. "\ {3 \}\. [0-9] \ {1, 3 \}/etc/sysconfig/network-scripts/ifcfg-eth0