Closes Homebrew/homebrew#34246.

This was reported in Tigerbrew, but is a worthwhile fix everywhere.

Fixes mistydemeo/tigerbrew#177.

This reverts commit dfd4dd12a41e1697ee9d5feac12cc1ea7c3a590e.

Fixes the problems from Homebrew/homebrew#17683 and Homebrew/homebrew#17685.

This reverts commit ac156b36d00ead5f225389f0a1d8069d0c1cce4a.

Make it no longer possible to override e.g. `brew install` with a
script if there is already a built-in Homebrew command named
`brew install`.

References Homebrew/homebrew#17673

This reverts commit 67d06b84d00a17cf43770eedf34e37e50e209741.

Closes Homebrew/homebrew#17683.
Closes Homebrew/homebrew#17685.

This reverts commit 225546a3ee2d3f22e185e47d4db6f6716a56669b.

This allows us to force using the system Ruby on OSX but allow
the development of Homebrew for Linux or Windows to not rely
on OSX paths.

Closes Homebrew/homebrew#17548.

@sceaga has discontinued his homebrew fork, so tigerbrew is now PPC/
Tiger users' best bet.

At your option: `brew --config -1`.

Shows full backtrace, which is useful. Now blank "raise" statements are the equivalent of admitting programmer error. The backtrace will be useful.

Because people use this in .bash_profile etc. We should be as fast as possible.

Let's not show weird error messages when user interrupts during various stages of brew initialization.

Tested by doing `for x in $(brew search); do brew install $x; done` and pressing CTRL-C at random short intervals.

Fixes a case where brew would find commands with wrongly-capitalized
user input on case-insensitive systems, then error out with a confusing
message when an invalid method was sent to Homebrew. e.g.:

> brew Update
Error: undefined method `Update' for Homebrew:Module

We don't want bug reports about this crap, even though the user REALLY should listen to the warning message. What actually happens is they blame us instead.

This kind of warning in particular:

warning: Insecure world writable dir /usr/local/bin in PATH

Rationale: some users insist on replacing the /usr/bin/ruby symlink
to point to another ruby on their system, which may break homebrew.
Use the full Framework path instead, which is less likely to be tampered with.

This also reorganizes the brew --config checks to reflect the different path.

Fixes Homebrew/homebrew#12009.

Closes Homebrew/homebrew#12333.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>

'which' only returns a Pathname or nil, and doesn't care about anything
sent to stderr, so just silence it by default and combine the two
methods.

Closes Homebrew/homebrew#12115.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Fixes Homebrew/homebrew#10829.

So upgrade can output errors but continue to upgrade the rest of the installation.

`brew install > file` should not give "export CC=/foo" output on Build Failures.

Also moved the "Using clang" output to brew when BuildError is thrown as that is where it is interesting, and not if you just do `brew --env`.

Adds a new class called `Tab` that acts as a recipt for install options. A
`Tab` can be serialized to a JSON file for future reference.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Also tidied error output. Still could be tidied quite a lot but I am still considering how best to go about it.

Note this only happens if Homebrew is *not* installed sudo. Which is most of the time true.

Fixes Homebrew/homebrew#6899

Rationale: people break their installs by mixing sudo and non-sudo usage. They are used to having to `sudo port install` and shit like that, so I understand why the mixing happens.

* may be a problem if the constant is scoped (like A::B), but this is not the case
  (const.split('::').inject(Object) { |c, part| c.const_get part } would solve that)
* this was noticed in a comment of 9afc85ad but it has disappeared

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Because we should always be able to help. And I've checked, it works fine.

Because `gem instal` works too.