How to insert a line at the beginning of a file with sed?

Question

Im trying to insert a line containing these characters: ~o to the beginning of a file. Im using: sed -i '' "1s/^/~o \n/" macros But the newline option just doesn't do its job. How should I change it ? Thank you

Answer 1

You can use the insert command i:

sed '1i\TEXT TO INSERT' file

Explanation:

1     Addresses the first line
i     The insert command inserts the following
      text before(!) line 1
\     Required after i (in POSIX compatible versions of sed)
TEXT  The text to insert

Example:

sed '1i\Hello' <<< 'world!'

Output:

Hello
world!

---

Btw, i works even with newline characters:

sed '1i\Hello\n' <<< 'world'

Output:

Hello

world!