Text-processing Exercises

I. Text-processing Exercises

1. Find all IPv4 address of native in ifconfig command result

[Email protected] zhang]# ifconfig |tr-s "" |head-2 |tail-1| Cut-d ""-f3

2. Find out the maximum percentage value of partition space utilization

[Email protected] zhang]# DF |cut-c46-48 |SORT-NR |head-1

3, identify the user UID maximum user name, UID and shell type

[Email protected] zhang]# cat/etc/passwd |sort-t:-k3-n |tail-1 |cut-d:-f1,3,7

4. Find out the permissions of/tmp and display them digitally

[Email protected] zhang]# stat/tmp |head-4|tail-1 |cut-d "/"-f1 |cut-d "1"-f2

5. Count the number of connections to each remote host IP currently connected to this machine, and sort from large to small

[Email protected] zhang]# netstat-nt |cut-d:-f2 |tr-s "": "|cut-d:-f2 |sort-r |uniq-c

Two. grep exercises

1. Display the line in the/proc/meminfo file that begins with the size S; (Requires: use two ways)

[Email protected] zhang]# grep-i "^s"/proc/meminfo or [[email protected] zhang]# grep "^[ss]"/proc/meminfo or [[Email prote CTED] zhang]# egrep "^ (s|s)"/proc/meminfo

2. Display lines in the/etc/passwd file that do not end in/bin/bash

[[email protected] zhang]# grep "/bin/bash$"/etc/passwd

3. Show user RPC default shell program

[[email protected] zhang]# grep "^rpc\>"/etc/passwd |cut-d:-f7

4. Find out the two-bit or three-digit number in/etc/passwd

[[email protected] zhang]# grep "\<[0-9]\{2,3\}\>"/etc/passwd

5. 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] zhang]# grep-n "^[[:space:]]\+[^[:space:]]*"/etc/grub2.cfg

6. Find the line ending with ' LISTEN ' followed by 0, 1, or more whitespace characters in the result of the "Netstat-tan" command

[Email protected] zhang]# Netstat-tan |grep-n "\<listen[[:space:]]*$"

7. Add user bash, Testbash, basher, and Nologin (whose shell is/sbin/nologin) and then find the same row in the/etc/passwd file as the user name and shell

[[email protected] testdir]# grep "^\ ([[: Alnum:]]\+\):. *\1$"/etc/passwd or [[email protected] testdir]# grep "^\ (\<.*\ >\). *\1$ "/etc/passwd

Three. Egrep Practice

1. Displays the UID and default shell of the current system root, mage, or Wang user

[Email protected] zhang]# egrep "(Root|zhang)"/etc/passwd |cut-d:-f3,7

2. 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] zhang]# egrep "^\< ([[: Alpha:]]|_) +\>\ (\). *"/etc/rc.d/init.d/functions

3. Use Egrep to remove its base name in/etc/rc.d/init.d/functions

[[email protected] zhang]# echo "/etc/rc.d/init.d/functions" |egrep-o "[[: alpha:]]+$] or [[email protected] zhang]# Echo "/etc/rc.d/init.d/functions" |egrep-o "[^/]+$"

4. Use Egrep to remove the directory name of the path above

[Email protected] zhang]# echo "/etc/rc.d/init.d/fun.ctions" |egrep-o "^.*/"

5. Count the number of logins for each remote host IP address logged in as Zhang

[Email protected] zhang]# w|egrep "^zhang" |sort-nr |tr-s "" ":" |cut-d:-f3 |uniq-c

6. Use extended regular expressions to represent 0-9, 10-99, 100-199, 200-249, 250-255, respectively

"([0-9]| [1-9] [0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5] "

7. Display all IPV4 addresses in ifconfig command results

[Email protected] packages]# ifconfig |egrep "\< ([0-9]|[ 1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]) \.) {3} ([0-9]| [1-9] [0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]) \> "

Three. Job

1. Use regular expressions to represent IP addresses

[Email protected] packages]# ifconfig |egrep "\< ([0-9]|[ 1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]) \.) {3} ([0-9]| [1-9] [0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]) \> "

2. Use regular expression to indicate mobile phone number 11 13 17 15 18

grep "\<1[13578][0-9]{9}\>"

3. Use regular expressions to represent the ID number 18

Egrep "\< ([1[1-5]) | ( 2[1-3]) | (3[1-7]) | (4[1-6]) | (5[0-4]) | (6[1-5]) | (71|81|82)) ([0-9]) {4} (19|20) ([0-9]) {2} ((0[1-9]) | (1[0-2])) (0[1-9]| ([0-9]) | (2[0-9]) | (3[0-1])) ([0-9]) {3} ([0-9]| X) \> "filename

4. Use regular expressions to express mailboxes

[[email protected] testdir]# egrep "\b[[:alnum:]]+ (-|_) *[[:alnum:]]\[email protected] ([[: Alnum:]]+\.) +[[:alnum:]]+ "Mail

Four. Sed exercises

1. Delete all whitespace characters from the beginning of lines in the/etc/grub2.conf file that begin with whitespace

[Email protected] ~]# sed-r ' [email protected]^[[:space:]][email protected]@ '/etc/grub2.cfg

2. Delete all # and white space characters at the beginning of the line beginning with #, followed by at least one white-space character, in the/etc/fstab file

[[Email protected] ~]# sed ' s/^#[[:space:]]\+//'/etc/fstab

3. Add # At the beginning of each line of/etc/passwd

[[Email protected] ~]# sed ' s/^/#/'/etc/passwd

4. Add # to the beginning of the line in the/etc/fstab file that does not begin with #

[[Email protected] ~]# sed ' s/^[^#]/#/'/etc/fstab or [[email protected] ~]# sed-r ' s/^ ([^#].*]/#\1/'/etc/fstab

5, processing/etc/fstab path, use sed command to take out its directory name and base name

echo "/ETC/FST/SD" | Sed-r ' [email protected] (. *)/([^/]+/?) @\[email protected] ' take the base name Echo '/ETC/FST/SD ' | Sed-r ' [email protected] (. */) ([^/]+/?) [Email protected]\[email protected] ' fetch directory name or [[email protected] ~]# echo '/ETC/FSTAB/ASDD ' |sed-r ' [email protected][^/]+\/ [Email protected]@ ' Fetch directory name [[email protected] ~]# echo "/ETC/FSTAB/ASDD" |sed-r ' [email protected]^.*/@@ ' Take base name

6. Use SED to remove the IPv4 address of the ifconfig command

[Email protected] ~]# ifconfig |sed-n ' 2p ' |sed-r ' [email protected]^[[:space:]][email protected]@ ' |sed-r ' [email pro Tected]*[email protected]@ '

7. Statistics of all RPM files in the package directory on the CentOS installation CD. Number of repetitions of the second-to-last field

[email protected] packages]# ls *.rpm |sed-r ' [email protected]*\. (. *) \[email Protected]\[email protected] ' |sort |uniq-c

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Text-processing Exercises