grep for a particular pattern and remove few lines above top and bottom of the patter Post: 302171844

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Top Forums Shell Programming and Scripting grep for a particular pattern and remove few lines above top and bottom of the patter Post 302171844 by alex_5161 on Friday 29th of February 2008 05:20:02 PM

02-29-2008

Registered User

It could be done with nawk.
2 ways: getting a line numbers and skip line between; or
keep all the time last 6 (in your case) lines, and print 7-th back line.

Here is 1-st way solution:

Code:

 # prepare file for testing:
n=0; fl=for_removing_lines.txt; rmv_lbl="point of removing"; rm $fl; 
while [ $n -le 20 ];do  
   (( n++ )); echo "line $n">>$fl; 
   if [ $n -eq 10 ]; then 
      echo $rmv_lbl>>$fl; 
   fi; 
done;

 # geting line numbers to statr and END remuving 
pnt_ln=`nawk -v srch="$rmv_lbl" '{if($0~srch) print NR; }' $fl`; 
((rmv_st=pnt_ln-6)); 
((rmv_end=pnt_ln+6));     echo $pnt_ln, $rmv_st, $rmv_end

 # printing file without 6 lines before and after label line
nawk -v st=$rmv_st -v end=$rmv_end '{if( (NR <= st)||(NR >= end) ) print $0; }' $fl

alex_5161

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LEARN ABOUT NETBSD

zfgrep

ZGREP(1)						    BSD General Commands Manual 						  ZGREP(1)

NAME

     zgrep, zegrep, zfgrep -- print lines matching a pattern in gzip-compressed files

SYNOPSIS

     zgrep [grep-flags] [--] pattern [files ...]

     zegrep [grep-flags] [--] pattern [file ...]

     zfgrep [grep-flags] [--] pattern [file ...]

DESCRIPTION

     zgrep runs grep(1) on files or stdin, if no files argument is given, after decompressing them with zcat(1).

     The grep-flags and pattern arguments are passed on to grep(1).  If an -e flag is found in the grep-flags, zgrep will not look for a pattern
     argument.

     zegrep calls egrep(1), while zfgrep calls fgrep(1).

EXIT STATUS

     In case of missing arguments or missing pattern, 1 will be returned, otherwise 0.

SEE ALSO

     egrep(1), fgrep(1), grep(1), gzip(1), zcat(1)

AUTHORS

     Thomas Klausner <wiz@NetBSD.org>

BSD
								 December 28, 2003							       BSD