How do I use sed to replace all lines between two matching patterns (on OSX BSD)

1.2k Views Asked by vsiege At 04 April 2025 at 19:42

I would like to know how to:

Replace all lines between two matching patterns (not include the patterns - exclusive). Please note that these will be on separate lines.
Replace all lines between and including two matching patterns (inclusive). Please note that these will be on separate lines I have started the first, but its not producing the desired results (actaully no results so far). Please keep in mind that this is for sed on Mac OSX (BSD). The pattern in this case is two html comments on separate lines.

My shell script looks like this:

REPLACEWITH="Replacement text here"
sed -i '' -e "s&\(<!--BeginNotes-->\).*\(<!--EndNotes-->\)&\1$REPLACEWITH\2&" /Users/BlaNameHere/builds/development/index.php

In the head of my index.php file is this excerpt:

<!--BeginNotes-->
    <!--asdasd-->
    <script type="application/javascript">var Jaop;</script>
<!--EndNotes-->

example result a

<!DOCTYPE html>
<html>
    <head>
        <title></title>
        <!--BeginNotes-->
        Replacement text here
        <!--EndNotes-->
    </head>
    <body>

    </body>
</html>

example result b

<!DOCTYPE html>
<html>
    <head>
        <title></title>
Replacement text here
    </head>
    <body>

    </body>
</html>

Original Q&A

There are 2 best solutions below

glenn jackman On 07 January 2014 at 23:00

A perl one-liner:

perl -i -0777 -pe 's/(<!--BeginNotes-->).*(<!--EndNotes-->)/$1'"$REPLACEWITH"'$2/s' index.php

This uses the -0777 option to read the entire file as a single string, which requires the s modifier on the s///s command

That one-liner is roughly equivalent to

perl -e '
    # read the file as a single string
    open $in, "<", "index.php";
    my $text;
    {
        local $/; 
        $text = <$in>;
    }
    close $in;

    # transform the string
    $text =~ s/(<!--BeginNotes-->).*(<!--EndNotes-->)/$1'"${REPLACEWITH}"'$2/s;

    # write out the new string
    open $out, ">", "index.php.tmp";
    print $out $text;
    close $out;

    # over-write the original file
    rename "index.php.tmp", "index.php"; 
'

NeronLeVelu On 08 January 2014 at 09:04

sed -n ":b
$ !{
   N
   b b
   }
$ {
   s|\(<!--BeginNotes-->\).*\(\n\)\([[:blank:]]*\)\(<!--EndNotes-->\)|\1\2\3${REPLACEWITH}\2\3\4|
   p
   }" /Users/BlaNameHere/builds/development/index.php

You need to load the file into the buffer becasue sed work line by line

How do I use sed to replace all lines between two matching patterns (on OSX BSD)

There are 2 best solutions below

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