mxcl/homebrew — Issue #9000: Install Script Fails on previously owned mac
Author: ajray
Created: 2011-12-06 17:27:38+00:00
State: open

my guess is that homebrew was previously installed, but installation fails with a lot of messages like:
Library/Formula/zookeeper.rb: Can't unlink already-existing object
Library/Formula/zsh.rb: Can't unlink already-existing object
Library/Formula/zsync.rb: Can't unlink already-existing object
Library/Formula/zzuf.rb: Can't unlink already-existing object
Library/Homebrew/LICENSE: Can't unlink already-existing object
Library/Homebrew/blacklist.rb: Can't create 'Library/Homebrew/blacklist.rb'
Library/Homebrew/build.rb: Can't create 'Library/Homebrew/build.rb'
Library/Homebrew/cleaner.rb: Can't unlink already-existing object
Library/Homebrew/cmd/: Can't create 'Library/Homebrew/cmd'
Library/Homebrew/cmd/--cache.rb: Failed to create dir 'Library/Homebrew/cmd'Can't create 'Library/Homebrew/cmd/--cache.rb'
Library/Homebrew/cmd/--cellar.rb: Failed to create dir 'Library/Homebrew/cmd'Can't create 'Library/Homebrew/cmd/--cellar.rb'
Library/Homebrew/cmd/--config.rb: Failed to create dir 'Library/Homebrew/cmd'Can't create 'Library/Homebrew/cmd/--config.rb'
Library/Homebrew/cmd/--env.rb: Failed to create dir 'Library/Homebrew/cmd'Can't create 'Library/Homebrew/cmd/--env.rb'

brew (the command) returns the error:
/usr/local/bin/brew:13:in `require': no such file to load -- cmd/help (LoadError)
from /usr/local/bin/brew:13