replace line with sed in csh

I am trying to change the content of a specific line in a batch of files. I thought that would be a piece of cake but for some reason, nothing happens, so I guess I am missing something. Line 8 should have been replace开发者_开发知识库d.

Here the csh script I used:

#!/bin/csh
#
# replace context in line xxx by yyy
# 2010/05/07

set files = `ls FILENAMEPART*`
echo $files
foreach file  ($files)
        sed  '8,8 s/1/2 /' $file 
end

thanks for suggestions

sed prints the resulting file (with the lines replaced) to stdout by default and leaves the source (input) file untouched. Use the -i option for in-place editing, which means that the changes are made directly in $file.