Prepend Text to a File at the Command Line
Prepending text to a file at the command line is a fiddly business. Here are a few ways to do it:
Using the clipboard
On OS X
cat file.txt | pbcopy && echo "Text to prepend" > file.txt && pbpaste >> file.txt
On Linux, with xclip
cat file.txt | xclip -i && echo "Text to prepend" > file.txt && xclip -o >> file.txt
Using a temporary file
echo "Text to prepend" | cat - file.txt > /tmp/tempfile && mv /tmp/tempfile file.txt
Using ed
echo '0a Text to prepend . w' | ed file.txt
Using sed (my favourite)
sed -i '1i Text to prepend' file.txt
No doubt there are more—and better?—ways to do this: let me know if so.
David suggests using sponge:
(echo "text to prepend"; cat file.txt) | sponge file.txt
