Extract string following another string in bash?

Question

I have the following string:

[1360308597] SERVICE NOTIFICATION: qreda;demo-jms2;OutConnectorResponse;notify-service-by-email;CRITICAL ConsumerCount=0[1360308817] SERVICE NOTIFICATION: qreda;demo-jms2;Disk Space;CRITICAL;notify-service-by-email;DISK CRITICAL - free space: /data 3018 MB (10% inode=92%):

In the above string I want to extract the string following demo-jms2. Here demo-jms2 occurs twice. I want to get all words following demo-jms2 so the answer should be OutConnectorResponse and Disk Space.

Community · Accepted Answer · 2020-06-20 09:12:55Z

3

What you want is positive look-behind:

$ grep -Po '(?<=demo-jms2;)[^;]+' file
OutConnectorResponse
Disk Space

Options:

-P, --perl-regexp PATTERN is a Perl regular expression

-o, --only-matching show only the part of a line matching PATTERN

Explanation:

(?<=demo-jms2;) # Positive lookbehind: match the follow after literal demo-jms2;
[^;]+           # Match one or more non ; characters

Edit:

To filter duplicates from the results pipe through sort -u:

$ grep -Po '(?<=demo-jms2;)[^;]+' file 
OutConnectorResponse
Disk Space
OutConnectorResponse
Disk Space

$ grep -Po '(?<=demo-jms2;)[^;]+' file | sort -u
Disk Space
OutConnectorResponse

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Feb 8, 2013 at 9:33

Chris Seymour

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2 Comments

RP89 Over a year ago

Hi Sudo, How can I remove duplicates from this grep? if Disk Space comes 2 times...

RP89 Over a year ago

Hi Sudo,How can I separate the result with comma? for eg : Disk Space,OutConnectorResponse

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