Shallow

Shallow[expr] prints as a shallow form of expr. 

Shallow[expr,depth] prints with all parts of expr below the specified depth given in skeleton form. 

Shallow[expr,{depth,length}] also gives parts whose lengths are above the specified limit in skeleton form. 

Shallow[expr,{depth,length},form] uses skeleton form for any parts that match the pattern form. 

Please visit the official Wolfram Language Reference for more details and examples on core symbols.