CODEWITHSUNDEEP
regexlinuxgrep
Goku
Goku

Reputation: 534

grep occurrences after match

I'm trying to grep the occurrences for 2 scenarios: 1. before the 1st space 2. before the end of the line

Example

-Dcatalina.base=/apps/kio/jal/current/mi_loki_porf -Dcatalina.home=/apps/kio/jal/current/mi_loki_porf
-Djava.io.tmpdir=/apps/kio/jal/current/mi_loki_porf/temp org.apache.catalina.startup.Bootstrap start

  1. I wanted to extract the occurences after the word '-Dcatalina.base=' before the 1st space and that would be /apps/kio/jal/current/mi_loki_porf

  2. Extract the occurences after the word '-Dcatalina.base' but before the end of line and that would be /apps/kio/jal/current/mi_loki_porf -Dcatalina.home=/apps/kio/jal/current/mi_loki_porf

Also, how should I approach if I've no idea about the occurences after the match, say ocurrences after '-Dcatalina.base=' can be words or alphanumeric or can be only special characters 

-Dcatalina.base=*(76yhg5)
or -Dcatalina.base=123345
or -Dcatalina.base=hellohowareyou
or -Dcatalina.base= *&^%$

What I've tried

grep -Po '(?<=-Dcatalina.base=).*' my.log

and it gives me the entire match after -Dcatalina.base

Upvotes: 0

Views: 56

Answers (1)

Toto
Toto

Reputation: 91518

Using perl, you can do:

perl -nE '/(?<=-Dcatalina\.base=)(\S+).*/ && say $1,"\n",$&' my.log

This will apply the regex on every line of the file my.log and print if it matches.

Explanation:

/                       : regex delimiter
  (?<=                  : positive lookbehind
    -Dcatalina\.base=   : literally
  )                     : end lookbehind
  (\S+)                 : group 1, 1 or more non space
  .*                    : 0 or more any character but newline
/                       : regex delimiter

&&                      : logical and, the following is executed only if the regex matches
say $1,"\n",$&          : print content of group 1, a line break and the whole match

Result for given example:

/apps/kio/jal/current/mi_loki_porf
/apps/kio/jal/current/mi_loki_porf -Dcatalina.home=/apps/kio/jal/current/mi_loki_porf

Upvotes: 1

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