output redirection operators

gistfile1.txt

    output redirection where α is a command and ß and γ are filenames
    ------------------------------------------------------------------
      α > ß         only regular output                              - override
      α >> ß        only regular output                              - append
      α 2> ß        only error output                                - override
      α 2>> ß       only error output                                - append
      α 2>&1> ß     both regular output and error output, merged     - overide
      α 2>&1>> ß    both regular output and error output, merged     - append
      α >ß 2>γ      both regular output and error output, separately - both override
      α >>ß 2>>γ    both regular output and error output, separately - both append
      α >ß 2>>γ     both regular output and error output, separately - regular override, error append
      α >>ß 2>γ     both regular output and error output, separately - regular append, error override