How can I prepend a string to the beginning of each line in a file?

Question

I have the following bash code which loops through a text file, line by line .. im trying to prefix the work \'prefix\' to each line but instead am getting this error:

Answer 1

You don't need sed, just concatenate the strings in the echo command

while IFS= read -r line; do
    echo "prefix$line"
done < filename

Your loop iterates over each word in the file:

for line in `cat file`; ...