Re: Support of '^' as alias for 'HEAD^'

From: Jeff King <peff@peff.net>
Date: Jul 15, 2012, 07:44 UTC
Message-ID: <20120715074441.GA18385@sigill.intra.peff.net>
In-Reply-To: <CAAa3hFMNf_wA22ngypSu379jr31r3L3yAjTkvDUd_L-mVwPJkA@mail.gmail.com>

On Sun, Jul 15, 2012 at 01:24:18AM +0300, Zeeshan Ali (Khattak) wrote:

> > Think what "log ^^ origin" would mean.  Is it "log ^HEAD^ origin"?
> > Is it "log HEAD^^ origin"?  They mean totally different things.
> 
> Sorry for my ignorance here but what does ^ *before* HEAD even mean? I

It means "not" (before "HEAD" or any other commit specifier). See "Specifying Ranges" in "git help revisions".

Show 7 quoted lines

> > Compared to that, at least ~<n> does not have such ambiguity within
> > the context of Git (having to quote is an ambiguity within the
> > context of using Git with shells that support dirstacks in their
> > tilde expansion).
> 
> Don't know whats dirstacks support either but that I guess just means
> that bash (the shell I have always used) doesn't do that.

Bash does support them, but you may not use them personally. Here are some examples of how a more bare "~" can go wrong:

  $ set -x
  [this instructs the shell to show us what it is executing]

  $ git log ~
  + git log /home/peff
  [oops, the shell expanded our home directory and passed it to git]

  $ git log ~1
  + git log '~1'
  [this one works ok, but...]

  $ pushd /tmp
  $ pushd $HOME
  $ git log ~1
  + git log /tmp
  [oops, pushd users cannot use ~<n> without quoting]

-Peff