Add contents of 1 file to the top of another file

Question

I need to insert text from 1 file at the top of a large number of files in a directory and its subdirectories. I have been able to do this successfully on a file by file basis using ed:

ed -s FileToAddTo.txt <<< $'0r TextToAdd.txt\nw'

However, when I replace FileToAddTo.txt with *.txt, nothing happens. How can I modify this, or use another Unix command such as sed, to add the contents of TextToAdd.txt recursively to all files in a directory ending with a specific extension? e.g

ed -rs *.txt <<< $'0r TextToAdd.txt\nw'

Please note that the code above this line does not work, it merely demonstrates what I would like to achieve.

Answer 1

Like this:

cat TextToAdd.txt FileToAddTo.txt > $$.tmp && mv $$.tmp FileToAddTo.txt

i.e. cat the new header file and the original file into a temporary file and then, if it was successful, rename the temporary file as the original.

And to run recursively !! PLEASE TEST ON BACKED UP DATA!!!

find . -type f -name "*.txt" -exec sh -c "cat TextToAdd.txt {} > $$.tmp && mv $$.tmp {}" \;

Answer 2

This works pretty well for me:

$ for fn in `find . -name '*.txt'`; do; cat textToAdd.txt $fn > $$.tmp && mv $$.tmp $fn; done;

Answer 3

Based on this, you can try:

for fn in `ls -R /folderName`; do cat "$fn" >> fileName;  done