Regular expressions can be used to search for some unspecified or even invisible characters.
Searching with regular expressions is different from searching with wildcards. LibreOffice Writer only supports searching with regular expressions.
You can use regular expressions when you find and replace text in a document. For example, "s.n" finds "sun" and "son".
Clickto expand the dialog.
Select thecheck box.
In thebox, type the search term and the regular expression(s) that you want to use in your search.
The regular expression for a single character is a period (.).
The regular expression for zero or more occurrences of the previous character is an asterisk. For example: "123*" finds "12" "123", and "1233".
The regular expression combination to search for zero or more occurrences of any character is a period and asterisk (.*).
The regular expression for the end of a paragraph is a dollar sign ($). The regular expression character combination for the start of a paragraph is a caret and a period (^.).
The regular expression for a tab character is \t.
A search using a regular expression will work only within one paragraph. To search using a regular expression in more than one paragraph, do a separate search in each paragraph.