Re: Print line from file only once even if occurrence of pattern is more than once in the line

You most likely have a loop over lines doing different checks.

Use next after the first successful match to parse the next line.

Otherwise you should show us some code of what you tried, such that we understand were your problem is.

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)}

Comment on Re: Print line from file only once even if occurrence of pattern is more than once in the line

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Re^2: Print line from file only once even if occurrence of pattern is more than once in the line by jayu_rao (Sexton) on Mar 29, 2015 at 17:59 UTC
Thanks Rolf. You are right. The code snippet is as below: `my @log_patterns = ( qr/ERROR/, qr/Error/, qr/FATAL/i, qr/critical/i, ); my @log_lines=<$read_tmp_log>; my $i; my $j; for (@log_patterns){ for $i (0..$#log_lines) { next unless $log_lines[$i] =~ $_; my $a = $i - 5 < 0 ? 0 : $i - 5;; my $b = $i + 5 > $#log_lines ? $#log_lines : $i + 5; print $output_file "\n"; for $j($a..$b){ print $output_file $log_lines[$j]; } } }` [download]	[reply] [d/l]
Re^3: Print line from file only once even if occurrence of pattern is more than once in the line by pme (Monsignor) on Mar 29, 2015 at 18:10 UTC
Hi jayu_rao, Try to do this way: `while(<$read_tmp_log>) { # reads input line if ( /error\|fatal\|critical/i ) { # if the line contains error, fata +l or critical case insensitively ... # process data } }` [download]	[reply] [d/l]
Re^4: Print line from file only once even if occurrence of pattern is more than once in the line by jayu_rao (Sexton) on Mar 29, 2015 at 18:22 UTC
Thanks pme. Reason why I used two for loops is that I need to print 5 lines before and after the pattern occurrence and I did not know how I could achieve it using while loop as per your suggestion. I tried earlier as well but in vain. Could you or anyone please help in shedding some more light on it, if you are aware? Regards, Jay	[reply]
Re^5: Print line from file only once even if occurrence of pattern is more than once in the line by pme (Monsignor) on Mar 29, 2015 at 18:40 UTC
Re^4: Print line from file only once even if occurrence of pattern is more than once in the line by jayu_rao (Sexton) on Mar 29, 2015 at 19:18 UTC
Thanks pme. That had just three lines before the occurrence of a pattern. My requirement is something like this: The line could have text such as: "ERROR - Critical error" or "ERROR - <module> threw an error" or "FATAL - Fatal error" or "java.lang.OutOfMemoryError" and I needed 5 lines before the matched line, matched line and 5 lines after the matched line to be printed. Note that the lines could occur immediately after one another and I would like to have output print only once in such cases.	[reply]
Re^5: Print line from file only once even if occurrence of pattern is more than once in the line by Cristoforo (Curate) on Mar 30, 2015 at 02:18 UTC
Re^3: Print line from file only once even if occurrence of pattern is more than once in the line (double?) by LanX (Saint) on Mar 29, 2015 at 18:38 UTC
Ehm...What's the difference to the question you already asked two weeks ago? Print 5 lines before and after pattern match from a list Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :)} PS: Je suis Charlie!	[reply]
Re^4: Print line from file only once even if occurrence of pattern is more than once in the line (double?) by jayu_rao (Sexton) on Mar 29, 2015 at 19:11 UTC
Appreciate everyone's responses so far. The difference is subtle. In my earlier post, the output needed to have 5 lines before and after each occurrence of a pattern but now in this thread, I want the output to have 5 lines before the pattern, the matched line to be printed only once even if there are multiple occurrences of same pattern or different patterns within same line and 5 lines after the matched line. I hope I am able to express the difference.	[reply]