alias [ {+|-}gmrsL ] [ name[=value] ... ]
       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 expansion.  If the -g flag is present, define a global
       alias; global aliases are expanded even if they do not occur in
       command position:

              % perldoc --help 2>&1 | grep 'built-in functions'
                  -f   Search Perl built-in functions
              % alias -g HG='--help 2>&1 | grep'
              % perldoc HG 'built-in functions'
                  -f   Search Perl built-in functions

       If the -s flag is present, define a suffix alias: if the command
       word on a command line is in the form `text.name', where text is any
       non-empty string, it is replaced by the text `value text.name'.
       Note that name is treated as a literal string, not a pattern.  A
       trailing space in value is not special in this case.  For example,

              alias -s ps='gv --'

       will cause the command `*.ps' to be expanded to `gv -- *.ps'.  As
       alias expansion is carried out earlier than globbing, the `*.ps'
       will then be expanded.  Suffix aliases constitute a different name
       space from other aliases (so in the above example it is still
       possible to create an alias for the command ps) and the two sets are
       never listed together.

       For each name with no value, print the value of name, if any.  With
       no arguments, print all currently defined aliases other than suffix
       aliases.  If the -m flag is given the arguments are taken as
       patterns (they should be quoted to preserve them from being
       interpreted as glob patterns), and the aliases matching these
       patterns are printed.  When printing aliases and one of the -g, -r
       or -s flags is present, restrict the printing to global, regular or
       suffix aliases, respectively; a regular alias is one which is
       neither a global nor a suffix alias.   Using `+' instead of `-', or
       ending the option list with a single `+', prevents the values of the
       aliases from being printed.

       If the -L flag is present, then print each alias in a manner
       suitable for putting in a startup script.  The exit status is
       nonzero if a name (with no value) is given for which no alias has
       been defined.

       For more on aliases, include common problems, see the section
       ALIASING in zshmisc(1).
