The Text Processing tool and regular expression of the exercises

1. Find all the IPv4 addresses of the ifconfig command results in this machine.

[[email protected] ~]# ifconfig         #centos6下eth0       Link encap:Ethernet  HWaddr 00:0C:29:BA:F9:36             inet addr:192.168.99.99   bcast:192.168.99.255  mask:255.255.255.0           inet6 addr: fe80::20c:29ff:feba:f936/64 scope:link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:3670 errors:0 dropped:0  overruns:0 frame:0          tx packets:2963  errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000           rx bytes:341489  (333.4  kib)   TX bytes:354417  (346.1 kib) lo         Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:65536  Metric:1           rx packets:8 errors:0 dropped:0 overruns:0 frame:0           tx packets:8 errors:0 dropped:0  overruns:0 carrier:0          collisions:0  txqueuelen:0           rx bytes:600  (600.0 b)   TX bytes:600   (600.0&NBSP;B)           [[email protected] ~ ]# ifconfig         #centos7下eno16777736:  flags=4163<up, Broadcast,running,multicast>  mtu 1500        inet  192.168.99.100  netmask 255.255.255.0  broadcast 192.168.99.255         inet6 fe80::20c:29ff:fe01:b00c  prefixlen 64   scopeid 0x20<link>        ether 00:0c :29:01:b0:0c  txqueuelen 1000   (Ethernet)          RX packets 2804  bytes 242061  (236.3 kib)          rx errors 0  dropped 0  overruns 0  frame 0         TX packets 1855  bytes 201673  (196.9 kib)         tx errors 0  dropped 0 overruns  0  carrier 0  collisions 0lo: flags=73<UP,LOOPBACK,RUNNING>   mtu 65536        inet 127.0.0.1   Netmask 255.0.0.0        inet6 ::1  prefixlen  128  scopeid 0x10
2. Find out the maximum percentage of partition space usage.
[Email protected] ~]# dffilesystem 1k-blocks used Available use% mounted on/dev/sda2 41153856 2146548 36910 156 6%/tmpfs 953140 0 953140 0%/dev/shm/dev/sda1 1998672 40260 1853556 3%/boot[[e Mail protected] ~]# DF | Tr-s ' |cut-d '-f 5|tr-d%|sort-n|tail-1
3, identify the user UID maximum user name, UID and shell type
[Email protected] ~]# Getent passwd | Sort-t:-K 3-n | Cut-d:-F 1,3,7|TAIL-1
4. Find out the permissions of/tmp and display them digitally
[[email protected] ~]# stat /tmp  file:  '/tmp '   Size: 4096           Blocks: 8           IO Block: 4096   directoryDevice: 802h/2050d     Inode: 786433      Links: 7Access:  (1777/DRWXRWXRWT)   Uid:  (    0/    root)    Gid:  (     0/    root) context: system_u:object_r:tmp_t:s0access:  2016-07-11 19:00:12.017347722 +0800modify: 2016-08-08 18:58:01.445117085 +0800change:  2016-08-08 18:58:01.445117085 +0800 Birth: -[[email protected] ~]#  stat /tmp | head -4|tail -1|cut -d  ' ('  -f2|cut -d  '/'  - F1
5. Count the number of connections to each remote host IP currently connected to this machine, and sort by large to small.
[[email protected] ~]# netstat-nt|grep tcp|tr-s ' |cut-d '-F 5|cut-d:-F 1|UNIQ-C|SORT-NR
6. Display the line in the/proc/meminfo file that starts with the size s (requires: use two ways)
[Email protected] ~]# cat/proc/meminfo |grep-i ^s #方法1 [[email protected] ~]# cat/proc/meminfo |grep-e ' ^s|^s ' #方法2 [[email protected] ~]# cat/proc/meminfo |grep ' ^[ss] ' #方法3
7. Display lines in the/etc/passwd file that do not end in/bin/bash
[Email protected] ~]# CAT/ETC/PASSWD | Grep-v '/bin/bash$ '
8. Show user RPC default shell program
[Email protected] ~]# CAT/ETC/PASSWD | grep ' ^rpc\> ' |cut-d:-F 7
9. Find out the two-bit or three-digit number in/etc/passwd
[Email protected] ~]# grep-e ' \<[1-9][0-9]\>|\<[1-9][0-9]{2}\> '/etc/passwd
10. Display a line in a/etc/grub2.cfg file that starts with at least one whitespace character and that is followed by a non-whitespace character
[[email protected] ~]# grep ' ^[[:space:]]\+[^[:space:] '/etc/grub2.cfg [[email protected] ~]# grep-e ' ^[[:space:]]+[^[: Space:] '/etc/grub2.cfg

11. Find the line that ends with "LISTEN" followed by any number of whitespace characters in the result of the "Netstat-tan" command
[Email protected] ~]# Netstat-tan | grep ' listen[[:space:]]*$ '
12. Add user bash, Testbash, basher, and Nologin (whose shell is/sbin/nologin), then find the line in the/etc/passwd file with the name of the shell
[Email protected] home]# cat/etc/passwd |grep ' ^\<\ (. *\) \>.*\b\1\b$ '
13. Display three user root, Mage, Wang's UID and default shell
[[email protected] home]# grep-e ' ^ (root|mage|wang) '/etc/passwd | Cut-d:-f3,7
14. Find the line at the beginning of the/etc/rc.d/init.d/functions file that has a word (including an underscore) followed by a parenthesis
[[email protected] home]# grep ' ^\<[[:alpha:]_]\+\> () '/etc/rc.d/init.d/functions
15. Use Egrep to remove the base name from the/etc/rc.d/init.d/functions
[Email protected] home]# echo "/etc/rc.d/init.d/functions" | GREP-E-O ' [^/]+/?$ '
16. Use Egrep to remove/etc/rc.d/init.d/functions directory name
[Email protected] home]# echo "/etc/rc.d/init.d/functions" | GREP-E-O ' ^/.*/'
17. Count the number of logons per remote host IP address logged in as root
[Email protected] ~]# Last | GREP-E-O "^root\>.* (([0-9]|[ 1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]) \.) {3} ([0-9]| [1-9] [0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])) "| Tr-s ' |cut-d '-f3|uniq-c
18. Count the number of occurrences of each word in the/etc/init.d/functions file and display it from high to low by frequency
[Email protected]/]# Cat/etc/init.d/functions | Tr-cs ' [: Alpha:] ' \ n ' |sort|uniq-c|sort-t '-k1-nr
19, from the file Haoma the regular expression of the identity card number
[Email protected]/]# grep-e ' [1-9][0-9]{5}1[0-9]{10}[0-9xx]| [1-9] [0-9] {5}200[0-9]{8}[0-9xx]| [1-9] [0-9] {5}201[0-6][0-9]{7}[0-9xx] ' Haoma
20, from the file Haoma use regular expression to represent the mobile phone number
[Email protected]/]# grep-e-o "(\+86)? 1[38][0-9]{9}|14[57][0-9]{8}|15[0-35-9][0-9]{8}|17[0678][0-9]{8}" Haoma
21, from the file Haoma The regular expression represents the mailbox
[[email protected]/]# grep-e-o ' [a-za-z0-9]+[[:alnum:]\.\_-]*@[a-za-z0-9]+[[:alnum:]\.\_-]* ' Haoma
22, from the file Haoma the regular expression of QQ number
[Email protected]/]# grep-e-o ' \b[1-9][0-9]{4,12}\b ' Haoma

This article is from the "Linux Operational Learning path" blog, please be sure to keep this source http://fengliang.blog.51cto.com/3453935/1835907
The Text Processing tool and regular expression of the exercises