A shelf is 'une étagère' (fem.) in French.
étagère
I'm putting the book on the shelf.
l'étagère (fem.) is the shelf in French.
estante
You could either say une étagère (a shelving unit, a set of shelves) or un petit placard (a cupboard, a small cabinet).
シェルフ Sherufu
Roland Garros
I found a few sites that say the shelf life is two years.
A bookcase is 'une bibliothèque' or 'une étagère' (closer to a shelf) in French.
to say is the verb 'dire' in French.
Textbook translates to French to be un manuel scolaire.
To say something is firmly attached to another object, you may say, "bolted on." As in: The nail is bolted on to the board. However, if you are describing a firmly attached object, for example, a shelf, you can say, "the bolted-on shelf."