Grep and inserting a string

I have a text file with a bunch of file paths such as -

开发者_如何学Cweb/index.erb

web/contact.erb

...

etc. I need to append before the

</head>

a line of code, to every single file, I'm trying to figure out how to do this without opening each file of course. I've heard sed, but I've never used it before..was hoping there would be a grep command maybe?

Thanks

xargs can be used to apply sed (or any other command) to each filename or argument in a list. So combining that with Rom1's answer gives:

xargs sed -i 's/<\/html>/myline\n<\/html>/g' < fileslist.txt

while read f ; do
    sed -i '/<\/head>/i*iamthelineofcode*' "$f"
done <iamthefileoffiles.list

or

sed -i '/<\/head>/i*iamthelineofcode*' $(cat iamthefileoffiles.list)