Remove only first line break

I have quite a few files where I want to get rid of a particular line break. The line always begins with "Title:" and so I tried the following command:

find . -type f -exec sed -i 's/^Title: \n\t*/Title:/g' {} \;

But from what I understand, sed only handles one line at a time, and so the above won't work. Is there a way to remove a line break (in multiple files), but only if the line begins with some string?

Solution

With GNU sed, you may use

sed '/^Title: $/{N;s/.*\n\t*\(.*\)/Title:\1/}'

See the online sed demo

Details

/^Title: $/ - finds a line with contents equal to Title:
{N;s/.*\n\t*$.*$/Title:\1/} - a block executed once the line above is found:
- N - gets the next line and appends a newline and that line to the pattern space
- s/.*\n\t*$.*$/Title:\1/ - replaces the pattern space (that holds two lines now) using the .*\n\t*$.*$ pattern that matches
  - .* - any 0+ chars
  - \n\t* - a newline and 0+ tabs
  - $.*$ - Capturing group 1: any 0+ chars
  - /Title:\1/ - replacement pattern, Title: and the value inside Group 1.