regex [a-z] for Hebrew letters?

[user743]

is there a regex for Hebrew letters similar to [a-z] or /d?

[DaleDe]

You might try unicode characters or the number entities for them. Generally all alphabets in unicode are in numeric sequence but occasionally an extra letter or two creeps in depending on the history of that particular alphabet.

Dale

[DiapDealer]

\p{L} will find almost any letter character in any language.
\p{Lu} for uppercase only.
\p{Ll} for lowercase only.

\p{script=Hebrew} or just \p{Hebrew} should also work with the calibre editor's regex engine.

(Naturally, the above will only work with actual unicode characters. They wont help you if entities are being used to represent characters [Hebrew or otherwise])