Sponsored Content
Top Forums Shell Programming and Scripting Would like to print 3 lines after a regular expression is found in the logfile Post 302544901 by joachimshaun on Friday 5th of August 2011 10:32:25 AM
Old 08-05-2011
Would like to print 3 lines after a regular expression is found in the logfile

I would like to print 3 lines after a regular expression is found in the logfile. I'm using the following code:
Code:
grep -n "$reg_exp" file.txt |while read LINE ;do i=$(echo $LINE |cut -d':' -f1 ) ;sed -n "$i,$(($i+3))p" file.txt ;done

The above code things works fine,but sometimes gives erroneous results. In my case i'm searching for the expression X104 in the logfile. Sometimes X104 will contain only 1 line to print and after printing that .It also prints the next 3 lines after that, e.g:

(i)11/02/09 02:21:15 X104
Text : Unable to unlink/erase file
System Error Number: 13 (d) - The data is invalid.

(ii) Text : X104 disabled.

(iii) 11/03/09 01:01:03 web200
Text : Freespace on C: is at a critical level (694.55MB).
Text : X104 enabled per scheduled_reboot.
NSLOOKUP was successful. Please reload your
configuration.

(i) : I get the desired results, regexp is found and the next 3 lines are printed
(ii) : regexp is matched (contains only 1 line) and printed, but I receive the next 3 lines (including the newline) which I find not useful for me.

Can anyone help me out

Last edited by Franklin52; 08-06-2011 at 04:49 PM.. Reason: Please use code tags for data and code samples, thank you
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

regular expression across some lines

I am trying to use regular expression to identify ONLY the commands that hasn't the word "tablespace" within it. a command starts with "create table" and ends with ; (semicolon) example file: create table first tablespace ; create table second ( BBL_CUSTOMER_NAME VARCHAR2(32), a... (7 Replies)
Discussion started by: ynixon
7 Replies

2. Shell Programming and Scripting

Regular expression in grep -E | awk print

Hi All, I have file.txt with contents like this: random text To: recipient@email.co.uk <HTML>S7randomtext more random text random text To: recip@smtpemail.com <HTML>E5randomtext more random text random text I need the output to look like this: 1,,,1,S7 1,,,1,E5 My code so... (9 Replies)
Discussion started by: terry2009
9 Replies

3. Shell Programming and Scripting

sed not printing lines before a regular expression.

Hey, I found a way to print the lines which is just before a regular expression, not including the expression. sed -n '/regexp/{n;p;}' myfile Now I'm looking for a way to print all lines, exept the regular expression and also the line before the same regular expression. Use code tags. (1 Reply)
Discussion started by: Livio
1 Replies

4. Shell Programming and Scripting

How to continue numbering after a regular expression has been found

Hello, I have a file starting with: fixedStep chrom=chrX start=1 step=1 0.930 0.955 0.972 0.985 0.993 0.995 0.994 0.990 0.984 0.971 0.942 0.944 0.971 fixedStep chrom=chrX start=200 step=1 0.987 (2 Replies)
Discussion started by: jpoldot
2 Replies

5. Shell Programming and Scripting

How to print the extended regular expression ?

Hello, How to print the field separator in awk? please see the following code: cat a.txt a 1s 2s 3s 4s b 2s 4s $ awk 'BEGIN{FS==" "} {print $2 $3 }' te 1s2s 2s4s I want to get the following output : 1s 2s 2s 4s How to realize this ? $ cat te a 1s,,2s 3s ... (11 Replies)
Discussion started by: 915086731
11 Replies

6. Programming

Perl: How to read from a file, do regular expression and then replace the found regular expression

Hi all, How am I read a file, find the match regular expression and overwrite to the same files. open DESTINATION_FILE, "<tmptravl.dat" or die "tmptravl.dat"; open NEW_DESTINATION_FILE, ">new_tmptravl.dat" or die "new_tmptravl.dat"; while (<DESTINATION_FILE>) { # print... (1 Reply)
Discussion started by: jessy83
1 Replies

7. UNIX for Dummies Questions & Answers

delete lines matching a regular expression

I have a very large file (over 700 million lines) that has some lines that I need to delete. An example of 5 lines of the file: HS4_80:8:2303:19153:193032 153 k80:138891 HS4_80:8:2105:5544:43174 89 k88:81949 165 k88:81949 323 0 * = 323 0 ... (6 Replies)
Discussion started by: pathunkathunk
6 Replies

8. UNIX for Dummies Questions & Answers

Finding lines with a regular expression, replacing them with blank lines

So the tag for this forum says all newbies welcome... All I want to do is go through my file and find lines which contain a given string of characters then replace these with a blank line. I really tried to find a simple command to do this but failed. Here's what I did come up with though: ... (2 Replies)
Discussion started by: Golpette
2 Replies

9. Shell Programming and Scripting

regular expression grouping across multiple lines

cat book.txt book1 price 23 sku 1234 auth Bill book2 sku 1233 price 22 auth John book3 auth Frank price 24 book4 price 25 sku 129 auth Tod import re f = open('book.txt', 'r') text = f.read() f.close() m =... (2 Replies)
Discussion started by: chirish
2 Replies

10. Shell Programming and Scripting

Regular expression to match multiple lines?

Using a regular expression, I would like multiple lines to be matched. By default, a period (.) matches any character except newline. However, (?s) and /s modifiers are supposed to force . to accept a newline and to match any character including a newline. However, the following two perl... (4 Replies)
Discussion started by: LessNux
4 Replies
PCREGREP(1)						      General Commands Manual						       PCREGREP(1)

NAME
pcregrep - a grep with Perl-compatible regular expressions. SYNOPSIS
pcregrep [-Vcfhilnrsvx] pattern [file] ... DESCRIPTION
pcregrep searches files for character patterns, in the same way as other grep commands do, but it uses the PCRE regular expression library to support patterns that are compatible with the regular expressions of Perl 5. See pcre(3) for a full description of syntax and semantics. If no files are specified, pcregrep reads the standard input. By default, each line that matches the pattern is copied to the standard out- put, and if there is more than one file, the file name is printed before each line of output. However, there are options that can change how pcregrep behaves. Lines are limited to BUFSIZ characters. BUFSIZ is defined in <stdio.h>. The newline character is removed from the end of each line before it is matched against the pattern. OPTIONS
-V Write the version number of the PCRE library being used to the standard error stream. -c Do not print individual lines; instead just print a count of the number of lines that would otherwise have been printed. If sev- eral files are given, a count is printed for each of them. -ffilename Read patterns from the file, one per line, and match all patterns against each line. There is a maximum of 100 patterns. Trailing white space is removed, and blank lines are ignored. An empty file contains no patterns and therefore matches nothing. -h Suppress printing of filenames when searching multiple files. -i Ignore upper/lower case distinctions during comparisons. -l Instead of printing lines from the files, just print the names of the files containing lines that would have been printed. Each file name is printed once, on a separate line. -n Precede each line by its line number in the file. -r If any file is a directory, recursively scan the files it contains. Without -r a directory is scanned as a normal file. -s Work silently, that is, display nothing except error messages. The exit status indicates whether any matches were found. -v Invert the sense of the match, so that lines which do not match the pattern are now the ones that are found. -x Force the pattern to be anchored (it must start matching at the beginning of the line) and in addition, require it to match the entire line. This is equivalent to having ^ and $ characters at the start and end of each alternative branch in the regular expression. SEE ALSO
pcre(3), Perl 5 documentation DIAGNOSTICS
Exit status is 0 if any matches were found, 1 if no matches were found, and 2 for syntax errors or inacessible files (even if matches were found). AUTHOR
Philip Hazel <ph10@cam.ac.uk> Last updated: 15 August 2001 Copyright (c) 1997-2001 University of Cambridge. PCREGREP(1)
All times are GMT -4. The time now is 10:30 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy