Insert/Add String to Beginning of a File

In a previous article, I showed you how to append a string to the end of file. Now I will show you how to insert a string to the beginning of a file in Linux. The solution is not as obvious as the former, but I will show you a quick and easy way using the standard Linux/Unix application sed.

Inserting a String to Beginning of File

1. Suppose you had a text file with the contents and you wanted to insert a string to the beginning:
   1st line
2nd line
3rd line

2. Run the command:
   sed -i '1i Top of the file!' <filename>
3. Now the file will look like this:
   Top of the file!
1st line
2nd line
3rd line


A brief explanation of the sed command parameters that we used:
-i : This will update the contents of the file and automatically save it
1i : This means, insert to the 1st line of the file