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As usual, he's eating while reading the newspaper.
Literal
Example [by-によって] he [topic-は] newspaper [object-を] reading-while meal [object-を] is-doing.
例によって ('as usual, as always') is a set adverbial phrase — literally 'according to example.' ~ながら ('while') attaches to the い-stem of 読む. 食事をしている ('is having a meal') uses 食事 ('meal') + を + する idiomatically, with the ~ている continuing state. Descriptive of a habitual scene.