hi,

I am trying to write a script to delete few lines from the existing files.

The requirement is as follows:
1. I need to grep for a pattern "abc" in a file and then grep for "xyz"
2. I need to delete all the lines (may be
2, 3 or more) between these 2 patterns.

what is the best possible way to do it. There ar multiple such files.
PLs let me know the possible solution.

if you have python here is one possible solution using regular expression

import re
pat = re.compile('abc\n.*?xyz\n', re.DOTALL)
print re.sub(pat, 'abc\n' + 'xyz\n', open('yourfile.txt').read())

Hi, thanks for the reply.
I tried running the script but it does not delete the lines between the two patterns.

==> input file: input.txt

==> awk action file: action.txt

BEGIN {
first = 0
}
{
if ( first == 0 )
{
print $0
if ( $0 ~/abc/ )
{
first = 1
}
}
else
{
if ( $0 ~ /xyz/ )
{
print $0
first = 0
}
}
}

==> run:
$ awk -f action.txt input.txt
to get the output on the screen

Luke Chi

Do you need to delete the lines that include the patterns or just the lines inbetween?

This perl command will do an inline edit of your file and delete the inbetween lines as well as the pattern matching lines.

perl -pi -e 'if(/abc/../xyz/){s/^.*$//s}' file.txt

This one will only delete the lines inbetween the matched the patterns.

perl -pi -e 'if(/abc/../xyz/){s/^.*$//s unless /(abc|xyz)/}' file.txt

Here's another way of writting the first command.

perl -ni -e 'print unless(/abc/../xyz/)' file.txt