How can I search matching pattern (stored in a variable) in a file using awk?

Question

I have a log file in which I need to check if there are any error messages, if there are, extract the error message to another file.

Like this I may have error file for the different file have different log patterns. So how can I search matching pattern using a variable?

As I want to create one generic .sh file for all log files. Suppose I have one file in which I want to search to pattern and print in another file $pat1="ERROR MESSAGE" $pat2="RAISE_ERROR_SEEN". I want all lines from file b/w these two patterns.

Using variable only.

Possibly related: [Pass shell variable as a /pattern/ to awk](https://unix.stackexchange.com/questions/120788/pass-shell-variable-as-a-pattern-to-awk) — steeldriver, Aug 12 '18 at 13:16
I tried to improve this but I still don't understand what you're asking? — slm, Aug 12 '18 at 13:21

Siva · Accepted Answer · 2018-08-16T22:24:15.760

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Try this,

 awk "/""$pat1""/,/""$pat2""/" test.log | grep -v "$pat3" > Error.bk

will print the context between $pat1 and $pat2
Since we have space in the first variable, use double quotes twice.

edited Aug 16 '18 at 22:24

answered Aug 12 '18 at 13:07

Siva

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score 0 · Answer 2 · answered Aug 12 '18 at 13:22

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in a more simple way:

grep -e "$pat1\|$pat2" filename > resultfile

answered Aug 12 '18 at 13:22

Hossein Vatani

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being careful with any regular-expression special characters in `$pat` – Jeff Schaller Aug 12 '18 at 13:57
you are right but I only considered his concern in his question. – Hossein Vatani Aug 12 '18 at 18:02
Hi, Actually I want to work on awk only as I need to add more filters code and logic to process all log files. – Vipin Sahu Aug 14 '18 at 08:47
OK!then please complete your question. – Hossein Vatani Aug 14 '18 at 11:11

How can I search matching pattern (stored in a variable) in a file using awk?

2 Answers2