How can I add a string to the beginning of each file in a folder in bash?

Question

I want to be able to prepend a string to the beginning of each text file in a folder. How can I do this using bash on Linux?

Answer 1

And you can do this using sed in 1 single command as well

for f in *; do
  sed -i.bak '1i\
  foo-bar
  ' ${f}
done