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(zsh.info)Invocation

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Invocation
**********

Invocation Options
==================

The following flags are interpreted by the shell when invoked to
determine where the shell will read commands from:

-c
     Take the first argument as a command to execute, rather than
     reading commands from a script or standard input.  If any further
     arguments are given, the first one is assigned to $0, rather than
     being used as a positional parameter.

-i
     Force shell to be interactive.

-s
     Force shell to read commands from the standard input.  If the -s
     flag is not present and an argument is given, the first argument
     is taken to be the pathname of a script to execute.

After the first one or two arguments have been appropriated as
described above, the remaining arguments are assigned to the positional
parameters.

For further options, which are common to invocation and the set
builtin, see Note: Options.

Options may be specified by name using the -o option.  -o acts like a
single-letter option, but takes a following string as the option name.
For example,

     zsh -x -o shwordsplit scr

runs the script scr, setting the XTRACE option by the corresponding
letter `-x' and the SH_WORD_SPLIT option by name.  Options may be
turned _off_ by name by using +o instead of -o.  -o can be stacked up
with preceding single-letter options, so for example `-xo shwordsplit'
or `-xoshwordsplit' is equivalent to `-x -o shwordsplit'.

Options may also be specified by name in GNU long option style,
`-OPTION-NAME'.  When this is done, `-' characters in the option name
are permitted: they are translated into `_', and thus ignored.  So, for
example, `zsh -sh-word-split' invokes zsh with the SH_WORD_SPLIT option
turned on.  Like other option syntaxes, options can be turned off by
replacing the initial `-' with a `+'; thus `+-sh-word-split' is
equivalent to `-no-sh-word-split'.  Unlike other option syntaxes,
GNU-style long options cannot be stacked with any other options, so for
example `-x-shwordsplit' is an error, rather than being treated like
`-x -shwordsplit'.

The special GNU-style option `-version' is handled; it sends to standard
output the shell's version information, then exits successfully.
`-help' is also handled; it sends to standard output a list of options
that can be used when invoking the shell, then exits successfully.

Option processing may be finished, allowing following arguments that
start with `-' or `+' to be treated as normal arguments, in two ways.
Firstly, a lone `-' (or `+') as an argument by itself ends option
processing.  Secondly, a special option `-' (or `+-'), which may be
specified on its own (which is the standard POSIX usage) or may be
stacked with preceding options (so `-x-' is equivalent to `-x -').
Options are not permitted to be stacked after `-' (so `-x-f' is an
error), but note the GNU-style option form discussed above, where
`-shwordsplit' is permitted and does not end option processing.

Except when the `sh'/`ksh' emulation single-letter options are in
effect, the option `-b' (or `+b') ends option processing.  `-b' is like
`-', except that further single-letter options can be stacked after the
`-b' and will take effect as normal.

Compatibility

Restricted Shell