Is there a problem with having /usr/local/bin before /usr/bin on the path in OS X?

By default, OS X 10.6 uses /usr/libexec/path_helper to add the following paths listed in the file /etc/paths:

/usr/bin
/bin
/usr/sbin
/sbin
/usr/local/bin

This means that /usr/bin comes before /usr/local/bin on the path. This results in the version of git installed by Xcode 4 in /usr/bin to be called instead of the version installed by Homebrew into /usr/local/bin.

Which leads me to my question, is there a problem with having /usr/local/bin come before /usr/bin in the path? Is there a specific reason that Apple defaults to having /usr/bin come before /usr/local/开发者_如何学编程bin?

How to change order of /usr/bin and /usr/local/bin

Is it a problem to move /usr/local/bin from the bottom of the file /etc/paths to the top? Doing so would impact the path for more than just when I fire up Terminal, since /usr/libexec/path_helper could be used by other resources (I'm uncertain about this).

While redundant, it seems safer for me to add /usr/local/bin to the path in ~/.bash_profile, which would mean that /usr/local/bin would be on the path twice.

No, and no. They're just weird ... local by definition should override.

I had trouble with same problem, and found the link below from googling.

https://discussions.apple.com/thread/3588837?start=0&tstart=0

They said that modifying /etc/paths is not a good idea for security reasons.

I found all the above useful, especially @Ohgyun Ahn's warning. So I suggest a compromise, which I just implemented:

Edit /etc/paths or /private/etc/paths (as it is in OS X 10.8) and override git alone. That escapes any security implications (unrelated to git, anyway) while implementing the up-to-date git for use by all programs that actually check the system-wide path.

1. Create a new directory to be used in the override, for example /usr/local/git-override/
2. Make new symlinks from git-override to homebrew's git programs. Just remake the git symlinks from /usr/local/bin.
3. add /usr/local/git-override to the top of (/private)/etc/paths.

Hope that's helpful to someone else.

I would just like to add that if you want to keep your PATH clean (no duplicate entries), you can add the following to your .bash_profile to achieve the desired effect:

# remove /usr/local/bin and /usr/bin
export PATH=`echo ":$PATH:" | sed -e "s#:/usr/local/bin:#:#g" -e "s/^://" -e "s/:$//"`
export PATH=`echo ":$PATH:" | sed -e "s#:/usr/bin:#:#g" -e "s/^://" -e "s/:$//"`
# add /usr/local/bin and /usr/bin in that order
export PATH="/usr/local/bin:/usr/bin:$PATH"

I learned that little trick from http://ntk.me/2013/05/04/path-environment-variable/

Edit: Very important! Don't get the order that those are removed wrong! If you do, sed won't work and you'll be left with /usr/local/bin:/usr/bin: as your PATH!

It's also worth noting that the others suggesting that this could introduce some security problems are correct. Please be sure to understand the risks involved!

Since modifying the order of /etc/paths seams to be discouraged for system stability and security ... here my solution which is based on the answer of @vmrob

read PATH < <(echo "$PATH" | sed  \
    -e 's/^/:/' -e 's/$/:/'       \
    -e 's_:/usr/local/bin:_:_g'   \
    -e 's_:/usr/local/sbin:_:_g'  \
    -e "s_:/usr/bin:/bin:_:$HOME/bin:/usr/local/bin:/usr/bin:/bin:_"        \
    -e "s_:/usr/sbin:/sbin:_:$HOME/sbin:/usr/local/sbin:/usr/sbin:/sbin:_"  \
    -e 's/^://' -e 's/:$//')
export PATH