How to add a line in many files

Question

I have many .html files and I need to add a meta tag after <head>'s start tag in each file.

How I can do that?

Can vim help me?

Chris Down · Accepted Answer · 2012-12-25 14:45:09Z

up vote 4 down vote accepted

In vim, you can do:

:%s/<head\b[^>]*>/& <meta foo="bar">/g

You could also do this in GNU sed, which would possibly be more fitting:

for file in *.html; do
    sed -i 's/<head\b[^>]*>/& <meta foo="bar">/g' "$file"
done

Be warned, -i breaks symlinks.

edited Dec 25 '12 at 14:45

answered Dec 25 '12 at 13:18

Chris Down
19.8k22873

	for file in .html; do sed -i 's/<head[^>>/& <link rel="shortcut icon" href="../favicon.ico" type="image/x-icon"/>/g'; done – chalist Dec 25 '12 at 13:32
	this error: sed: -e expression #1, char 90: unterminated `s' command – chalist Dec 25 '12 at 13:33
	thanks a lot. it's done :D. I love linux :) – chalist Dec 25 '12 at 13:41
	`sed -i.bkp` it will edit original files, and also take backup as filename.bkp – Rahul Patil Dec 25 '12 at 13:43
	If that HTML is HTML5, your regular expression will erroneously match `header` tags too. Make it match only if “head” ends at word boundary. – manatwork Dec 25 '12 at 13:50

PSivachandran · Answer 2 · 2012-12-25 14:24:10Z

sed -i '/PATTERN/ a\
    Line which you want to append' filename

for this example

sed -i '/<HEAD>/a <meta>' test.txt
<HEAD>
<HEAD>

Result :

<HEAD>
<meta>
</HEAD>

The above command will append new line after the string get matched. However this will give wrong result if file has input string as

<HEAD><TITLE></TITLE>
</HEAD>

Result:

<HEAD><TITLE></TITLE>
<meta>
</HEAD>  //which is wrong.

May be we can try this approach:

sed -i 's/<HEAD>/<HEAD><meta>/' filename

<head><foo> is legal in HTML, so this will not work as expected if such a condition exists. For example, this would result in <head><foo>\n<meta ...> in such a case.

2 Answers