Re: alias hl='$(history -n -2 -2) '

[Peter Stephenson <pws@csr.com>]

zzapper wrote:
> hi
> 
> alias hl='$(history -n -2 -2) '
> 
> The following attempts to emulate !-2 however if the command that is 
> recalled is itself an alias, it fails to interpret the alias.
> 
> Is this just hard-luck?

An overall summary is probably yes...  The $(...) construct doesn't
cause the text it outputs to be completely reevaluated, just output
onto the command line as a set of words.  This is substantially
different from what you want.

You could get the history part working better with

alias hl='eval "$(history -n -2 -2)" '

which takes the output from the history commands and treats it as a
command line (which is, of course, what it is).  The problem is
that the eval applies to the entire line, including anything you type
after "hl ".  I can think of nasty tricks involving functions to work
round that, but not any simple fix.

I presume you're trying to avoid bang-history for some reason.  If you're
not wedded to aliases you could use a zle function to retrieve specific
stuff from the history.

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



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