Find a specific word in a textfile and insert 2 new lines in front of it

Hello,

I've got a very basic question which I can't seem to figure out. I've got a textfile in which I want to find the word 'Observation_3'. Then I want to insert 2 new lines in front of the word 'Observation_3'. Can anyone help?

Thank you.

[Rik]

The easiest way tends to be to read the entire file and do the editing in memory. Then you overwrite the old file with the result.

[Walter Roberson]

fileread and regexprep are useful

[Sam]

Thank you!

Now I have the location in my file where I want to insert 2 new lines... How can I do this? I know how to use fopen and fwrite, but I can't seem to figure it out...

filetext = fileread('test2.txt');
expr = '\w*Observation_3\w*';
[startIndex,endIndex] = regexp(filetext,expr,'match');

 %Insert new line at position endIndex - 14;
 ...

[Rik]

insterttext=sprintf('%s\n%\s\n','hello','world');
newfiletext = [filetext(1:(endIndex-14)) insterttext filetext((endIndex-13):end)];