Regex to match lines that access a certain port and particular packets

CryptoTrader

2/20/23, 12:58 AM

New to Linux and the only way I can get this to work is by using the awk command unfortunately the main directions specify to not use awk.

this is what I got

#!/bin/sh
#comment Write a single RegEx to match the lines that access port 22 and only those packets
grep '\s22\s' hw0206.txt | awk {'print $4'}
#comment grep returns the whole line with matched string
#comment \s22\s regular expression to match any string containing 22 preceded or succeeded by white space

instructions

Write a single RegEx to match the lines that access port 22 and only those packets, and then return the IP address

Input file (hw0206.txt) Expected output of script
date time protocol ip-address port packet-size
2022-02-21 19:22:19 TCP 22.101.2.24 22 24
2018-22-22 02:25:12 UDP 10.221.7.22 2135 222
2200-05-22 22:26:22 UDP 22.122.6.62 2160 22
2012-22-20 15:43:22 TCP 10.121.7.222 22 122
1228-02-10 02:22:02 UDP 22.102.2.62 2089 22 
date time protocol ip-address port packet-size
2022-02-21 19:22:19 TCP 22.101.2.24 22 24
2018-22-22 02:25:12 UDP 10.221.7.22 2135 222
2200-05-22 22:26:22 UDP 22.122.6.62 2160 22
2012-22-20 15:43:22 TCP 10.121.7.222 23 122
1228-02-10 02:22:02 TCP 22.102.2.62 22 22
2100-05-25 21:26:22 UDP 22.112.63.62 2122 22

0 + 0

regex

Greenonline

2/20/23, 1:35 AM

Is this homework?

CryptoTrader

2/20/23, 11:11 PM

no, self paced tutorial. trying to teach myself

Score:2

Ubuntu

bac0n

2/20/23, 1:29 AM

With positive lookahead, you can match something that should not be part of the result:

grep -Po '(\d+\.){3}\d+(?=\s22\s)' hw0206.txt

In this case, I would prefer awk which gives a more readable solution:

awk '$5 == 22 {print $4}' hw0206.txt

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Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Regex to match lines that access a certain port and particular packets

TH: Regex เพื่อจับคู่บรรทัดที่เข้าถึงพอร์ตและแพ็กเก็ตเฉพาะ

RO: Regex pentru a potrivi liniile care accesează un anumit port și anumite pachete

RU: Регулярное выражение для сопоставления строк, которые обращаются к определенному порту и определенным пакетам.

VI: Regex để khớp các dòng truy cập vào một cổng nhất định và các gói cụ thể

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