Re: Expansion order

[Peter Stephenson <pws@xxxxxxx>]

Mads Martin Joergensen wrote:
> Hey together,
> 
> $ export LS_OPTIONS="-N --color=tty -T 0"
> $ alias ls='ls $LS_OPTIONS'
> $ ls
> /bin/ls: invalid option --
> Try `/bin/ls --help' for more information.
> 
> How come the zsh is doing the expansion in this case differently from
> csh, tcsh, bash and sh?

It's sh_word_split again.  You're using $LS_OPTIONS as a single word and
zsh is obliging.  The error message is confusing.

There are various possibilities:

alias ls="ls $LS_OPTIONS"

is the simplest, but if you want changes in LS_OPTIONS to be reflected
later on you need something else.

alias ls='ls $=LS_OPTIONS'

is the obvious.

More sophisticated:

typeset -xT LS_OPTIONS="-N --color=tty -T 0" ls_options
alias ls='ls $ls_options'

This allows for whitespace characters in the options as long as you
manipulate them through the array ls_options.

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070


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