LinuxQuestions.org - Sed pattern matching

Hi,

There probably several ways to tackle this. Probably? Yes, I don't know if there are any empty lines between the VirtualHost entries. I assume (dangerous, I know) that there are.

If so, here are 2 (one useful, one for fun):

Using awk:
awk 'BEGIN { FS="\n" ; RS="" } $3 !~ /ServerName www.something.com/ { print $0, "\n" }' infile

Don't know the level of experience you have with awk, so here's a nutshell explanation.

BEGIN { FS="\n" ; RS="" } => This sets the Field (FS) and Record (RS) separator. Normally awk reads entries one line at the time, from left to right (RS="\n" and FS=" "), this makes sure that a one paragraph (empty line being the record separator) is read.

$3 !~ /ServerName www.something.com/ { print $0, "\n" } => If field 3 does not match 'ServerName www.something.com', print the paragraph.

If something isn't clear: Just ask.

And if you really, really want to do this with sed:

Code:

#!/bin/bash



sed -n '

# if an empty line, check the paragraph

/^$/ b para

# else add it to the hold buffer

H

# at end of file, check paragraph

$ b para

# now branch to end of script

b

# this is where a paragraph is checked for the pattern

: para 

# return the entire paragraph

# into the pattern space

x

# look for the pattern, if there - delete, print all other paragraphs

/ServerName www.something.com/{d}

p

' $1

Hope this gets you going again.