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Apart from the trivial constant functions then, singularities are a fact of life, and we must learn to live with them.
-----Arfken, Weber, and Harris, Mathematical Methods for Physicists 7th ed, page 490
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The shell has no recycle bin or trashcan. After you remove a file, it's gone forever.
-----Richard Blum, Christine Bresnahan, Linux Command Line and Shell Scripting Bible 3rd ed, page 114
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