insert filename into file using SED (or AWK)

Shell Programming and Scripting
1

Hi,
I would like to insert a file's filename into the first line of that file - for a batch of files. Is this possible using SED? Thanks in advance.

2 
for file in `ls -1 *`
do
    echo "$file" > ./tmpfile
    cat "$file" >> ./tmpfile
    mv ./tmpfile "$file"
done

is one way to do this.

3

How about this:

for i in *; do
ex $i <<EOF
i
$i
.
wq
EOF
done

I doubt that it would be very easy to do it using sed, as sed writes to standard output. You would have to pull stunts like redirecting standard output to a file at the beginning of the script and changing that for every file that you want to change...