alias [ -g ] [ name[=value] ] ...
          With no arguments, print the list  of  aliases  in  the
          form  name=value on the standard output.  For each name
          with a corresponding value, define an alias  with  that
          value.   A trailing space in value causes the next word
          to be checked for alias substitution.  If the  -g  flag
          is  present,  define a global alias; global aliases are
          expanded even if they do not occur in command position.
          For  each  name with no value, print the value of name,
          if any.  The exit status is nonzero if a name (with  no
          value) given for which no alias has been defined.
     unalias name ...
          The alias definition, if any, for each name is removed.