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Find a string in textfile, erase $num lines after that string

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Top Forums Shell Programming and Scripting Find a string in textfile, erase $num lines after that string
# 1  
Old 09-09-2010
Find a string in textfile, erase $num lines after that string
I have a textfile containing text similar to the following pattern:

Code:
STRING1
UNIQUE_STRING1
STRING2
STRING3
STRING4
STRING5

STRING1
UNIQUE_STRING2
STRING2
STRING3
STRING4
STRING5

STRING1
UNIQUE_STRING3
STRING2
STRING3
STRING4
STRING5

I would like to somehow find for example UNIQUE_STRING3 and delete the line before, UNIQUE_STRING3, and the 4 lines after that string.
STRING1 to 5 is identical and repeated lots of time in this textfile, so I can not search for them.
Of course the script should be in sh, not bash.

Can someone help me? Smilie
Last edited by radoulov; 09-09-2010 at 10:54 AM.. Reason: Code tags, please!
# 2  
Old 09-09-2010
Try:
Code:
awk '"UNIQUE_STRING3"==$2{$0=$2}1' FS="\n" RS= ORS="\n\n" infile

Last edited by Scrutinizer; 09-09-2010 at 11:12 AM..
# 3  
Old 09-09-2010
No, doesnt seem to work.
Havent figured out exactly what that line tries to do yet, but it doesnt work when I test it.
# 4  
Old 09-09-2010
I get:
Code:
STRING1
UNIQUE_STRING1
STRING2
STRING3
STRING4
STRING5

STRING1
UNIQUE_STRING 2
STRING2
STRING3
STRING4
STRING5

UNIQUE_STRING3

Are you on Solaris? use /usr/xpg4/bin/awk or nawk instead of awk
# 5  
Old 09-09-2010
No, Im on freebsd.
I think there is a nawk available in ports, I will try that.
# 6  
Old 09-09-2010
I don't have sh to test this. (sh is linked to bash in Cygwin).
See if these work.

Code:
$
$
$ cat f11
STRING1
UNIQUE_STRING1
STRING1
STRING1
STRING1
STRING1
 
STRING2
UNIQUE_STRING2
STRING2
STRING2
STRING2
STRING2
 
STRING3
UNIQUE_STRING3
STRING3
STRING3
STRING3
STRING3
$
$
$ cat f11.sh
#!/usr/bin/bash
str="$1"
num=1
while read LINE
do
  if [ -z "$LINE" ]; then
    echo $LINE
    print_block="y"
    num=0
  elif [ "$num" -eq "2" -a "$LINE" = "$str" ]; then
    print_block="n"
  elif [ "$num" -eq "2" -a "$LINE" != "$str" ]; then
    echo $x
    echo $LINE
  elif [ "$num" -gt "2" -a "$print_block" != "n" ]; then
    echo $LINE
  elif [ "$num" -eq "1" ]; then
    x=$LINE
  fi
  num=`expr $num + 1`
done <f11
$
$ . f11.sh UNIQUE_STRING2
STRING1
UNIQUE_STRING1
STRING1
STRING1
STRING1
STRING1
 

STRING3
UNIQUE_STRING3
STRING3
STRING3
STRING3
STRING3
$
$
$ ## With Perl's "slurp" mode
$ perl -lne 'BEGIN{$/="\n\n"} while(/([\w\n]+)/mg){print $1,"\n" if !/UNIQUE_STRING2/}' f11
STRING1
UNIQUE_STRING1
STRING1
STRING1
STRING1
STRING1
 
STRING3
UNIQUE_STRING3
STRING3
STRING3
STRING3
STRING3
 

$
$
$ ## Using Perl arrays
$ perl -lne 'if (!/^$/){push @x,$_} elsif(/^$/ or eof) {if ($x[1] ne "UNIQUE_STRING2"){print for (@x)}; @x=()}
             END{if ($x[1] ne "UNIQUE_STRING2"){print for (@x)}}' f11
STRING1
UNIQUE_STRING1
STRING1
STRING1
STRING1
STRING1
STRING3
UNIQUE_STRING3
STRING3
STRING3
STRING3
STRING3
$
$
$

tyler_durden
# 7  
Old 09-09-2010
u can try?

Code:
# sed -E -e 'N;/UNIQUE_STRING3/P;/UNIQUE_STRING3/,+4d' infile
STRING1
UNIQUE_STRING1
STRING2
STRING3
STRING4
STRING5

STRING1
UNIQUE_STRING2
STRING2
STRING3
STRING4
STRING5

STRING1

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