As I understand it, brew doesn't put anything in /usr/local/bin that collides (has the same name as) an Apple distributed executable. Therefore, having /usr/local/bin in the path before /bin and /usr/bin shouldn't be an issue, because there should be no name collisions. *However, see the issues with ls and tar, and using other package aggregators like fink and port (MacPorts), way below.
Brew does one of two things that I know of that help manage name collisions:
Brew leaves unlinked kegs in the Cellar. To install stuff, brew leaves the tools where they are, and creates symbolic links to those tools in /usr/local/bin. For tools which brew doesn't want a name collision with, it doesn't create a symbolic link.- For many if not all of the standard tools which are also in
/bin and /usr/bin, brew prefixes the link in /usr/local/bin with a "g", so for instance, to perform an ls with a brew version, use gls. Simply do an ls -l in /usr/local/bin and look for the linked files - those are the ones brew put there. Note: The brew installed tools that must be accessed by their real names are found in /usr/local/Cellar/coreutils/8.21/libexec/gnubin.
I don't put /usr/local/bin in my path for two reasons - those reasons are at the bottom of my answer.
To assess the name collisions in your system, use brew doctor and look for this section -
Here's the brew doctor's output of interest:
Warning: /usr/bin occurs before /usr/local/bin
This means that system-provided programs will be used instead of those
provided by Homebrew. The following tools exist at both paths:
ctags
emacs
emacsclient
etags
ex
git
git-cvsserver
git-receive-pack
git-shell
git-upload-archive
git-upload-pack
rview
rvim
view
vim
vimdiff
vimtutor
xxd
Consider setting your PATH so that /usr/local/bin
occurs before /usr/bin. Here is a one-liner:
echo export PATH='/usr/local/bin:$PATH' >> ~/.bash_profile
The reason I don't put brew's tools first, in fact, not at all, is because the brew installed ls and tar commands do not handle the filesystem ACL properly, in fact, last time I checked (which was last week), they weren't handled at all. This is a BIG problem, and to avoid it altogether, along with the associated man page configuration issue that tags along with setting the $PATH right, I make sure I put the OSX related tools, especially those found in /bin and /usr/bin, first.
Another reason I don't even put /usr/local/bin in my path at all is because brew doesn't play well with others, and fink and port (MacPorts) have way more supported packages at present that I need NOW. For instance, I can get gnome-terminal with fink, but it would be a big effort to construct a formula and do the same with brew. So, I keep /sw and /opt in my search $PATH (for fink and port, respectively) and reference things I need from /usr/local/bin, including gnat, either spelled out, or I use bash alias's, or I source a setup file for an entirely different environment when I writing Ada code.
The thing is, it really depends on what you want and need at the time.
Here's an example of the ACL problem that I mentioned above.
With the standard OSX tools:
$ /bin/ls -le /var/root | head -7
total 24
drwx------+ 3 root wheel 102 May 28 2013 Desktop
0: group:everyone deny delete
1: user:_spotlight inherited allow list,search,readattr,readextattr,readsecurity,file_inherit,directory_inherit
drwx------+ 6 root wheel 204 Sep 19 14:22 Documents
0: group:everyone deny delete
1: user:_spotlight inherited allow list,search,readattr,readextattr,readsecurity,file_inherit,directory_inherit
and with the brew installed tools:
$ /usr/local/bin/gls -le /var/root
/usr/local/bin/gls: invalid option -- 'e'
Try '/usr/local/bin/gls --help' for more information.
and
$ /usr/local/bin/gls --help | grep -i acl
You'll get similar results with tar and I don't know home many other brew tools, but who can afford to have something break 6 months down the road because of an ACL problem!
