How to Manage Bash Paths on MacOS




Viewing your bash path

The easiest way to view your bash path is to run

env

Then visually parse the output looking for the PATH entry and then read that line.

A slightly better way to view your bash path is to run

env | grep -i path

This will eliminate all the environment variables that aren’t paths.

$ env | grep -i path
SQLITE_EXEMPT_PATH_FROM_VNODE_GUARDS=/Users/mark/Library/WebKit/Databases
PATH=/Users/mark/.rbenv/shims:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/go/bin:/usr/local/MacGPG2/bin:/opt/X11/bin:/Users/mark/bin:/usr/local/sbin:/usr/local/go/bin:/Users/mark/.cargo/bin
GOPATH=/Users/mark/code/go

Personally I find parsing a list delimited by : to be difficult. So I use a simple function to break the path apart, displaying each entry on its own line, and color coding it along the way. Here’s the function:

path() {
local blue="\033[1;34m"
local green="\033[0;32m"
local cyan="\033[0;36m"
local purple="\033[0;35m"
local brown="\033[0;33m"
local reset_color="\033[0m"
  echo $PATH | tr ":" "\n" | \
    awk "{ sub(\"/usr\",   \"$green/usr$reset_color\"); \
           sub(\"/bin\",   \"$blue/bin$reset_color\"); \
           sub(\"/opt\",   \"$cyan/opt$reset_color\"); \
           sub(\"/sbin\",  \"$purple/sbin$reset_color\"); \
           sub(\"/local\", \"$brown/local$reset_color\"); \
           print }"
}

After setting some local variables to hold bash color codes, the function echoes the $PATH environment variable, using the tr, or translate command, to convert each : into a new line character, \n. The output of tr is passed to awk which colorizes the output but substituting some key words into the same keywords surrounded by color codes.

Here’s a sample output:

Image showing output of path function

One advantage to this output is it is far easier to find duplicates or path elements that are out of order.

A path_helper primer

macOS includes a utility called path_helper. The utility hopes to simplify management of your path. Knowing about it, and working with it, is the key to simplifying your path.

path_helper relies upon two sets of information. First is a list of standard paths found in /etc/paths. On my macOS computer /etc/paths contains:

$ cat /etc/paths
/usr/local/bin
/usr/bin
/bin
/usr/sbin
/sbin

The second set of information used is the /etc/paths.d directory. Applications that make use of path_helper know to put a file at this location that contains their path element. Again from my computer, the contents of /etc/paths.d

$ ls -al /etc/paths.d
total 24
drwxr-xr-x    5 root  wheel   160B Sep 30  2018 ./
drwxr-xr-x  126 root  wheel   3.9K Sep 19 14:10 ../
-rw-r--r--    1 root  wheel    13B Oct 26  2016 40-XQuartz
-rw-r--r--    1 root  wheel    23B Feb  2  2015 MacGPG2
-rw-r--r--    1 root  wheel    17B Oct 25  2017 go

Looking at the go entry, for example, we see:

/usr/local/go/bin

Returning to the image showing the output of my path function, you can see the Go entry in the list. As well as entries for X-Quartz and MacGPG2. Also you can see the five standard path elements in positions 2 - 6. Obviously the /Users/mark/.rbenv/shims entry was pre-pended to $PATH. And it is also obvious that some things are getting added to the list twice.

Understanding that path_helper will seed $PATH with the standard elements, and any elements found in /etc/paths.d, it is now possible to clean up what is added to $PATH, and in what order they are added, in the bash configuration.

My bash configuration

My bash configuration is broken up into several files as the outgrowth of near constant tinkering and tweaking.

la -la ~/.dotfiles/bash/
total 136
drwxr-xr-x@ 12 mark  staff   384B Sep 19 14:12 ./
drwxr-xr-x@ 40 mark  staff   1.3K Aug 15 22:33 ../
-rw-rw-r--   1 mark  staff   7.3K Aug 25 22:11 bash_aliases
-rw-rw-r--@  1 mark  staff   389B May  5  2016 bash_bindkeys
-rw-rw-r--@  1 mark  staff   1.9K Jan 20  2016 bash_colors
-rw-rw-r--@  1 mark  staff   1.8K Mar 22  2016 bash_docker_functions
-rw-rw-r--   1 mark  staff    16K Aug 15 22:33 bash_functions
-rw-rw-r--   1 mark  staff   2.1K Sep 19 14:12 bash_profile
-rw-rw-r--   1 mark  staff   5.1K Sep 19 14:12 bashrc

(It is worth noting that the files are in my $HOME via symlinks.) The bash_profile file contains all the additions to my path.

I start off by clearing my $PATH and executing path_helper to seed to with the contents of /etc/paths and /etc/paths.d.

if [ -x /usr/libexec/path_helper ]; then
	PATH=""
	eval `/usr/libexec/path_helper -s`
fi

The -x conditional looks for an executable file; this allows the same bash_profile to be used on Linux machines without throwing errors.

For each element I want to add to $PATH I follow a similar pattern: test for the presence of the directory to be added, and if it is there, append it (or pre-pend it) to the variable. For example:

# set PATH so it includes user's private bin if it exists
if [ -d $HOME/bin ] ; then
  PATH="${PATH}:${HOME}/bin"
fi

Will add my personal bin directory to the list, at the end of the current list.

You can see my current bash_profile, and the rest of my bash configuration, in my GitHub dotfile repository. Here’s a sample from my bash_profile:

# set PATH so it includes user's private bin if it exists
if [ -d $HOME/bin ] ; then
  PATH="${PATH}:${HOME}/bin"
fi

# add Go path for Linux
if [ -d /usr/local/go/bin ] ; then
  PATH="${PATH}:/usr/local/go/bin"
  export GOPATH=$HOME/code/go
fi

# Enable path for Rust
if [ -d $HOME/.cargo/bin ] ; then
  PATH="${PATH}:$HOME/.cargo/bin"
fi

export PATH

Duplicate entries

Close reading of the path function output in the image above, and of the contents of /etc/paths.d, and of the sample bash_profile above, will show that the path for Go is in my $PATH twice. Once from the entry in /etc/paths.d and once from the lines in my bash_profile.

I have, and use, multiple computers running macOS. At work I have a pair of desktops and a laptop, and at home I have my personal laptop. Apparently I used a different method to install Go at work than I did at home. The method I used on my personal laptop created the /etc/paths.d entry, while the method I used at work did not. I can either remove the lines from bash_profile or add an entry to /etc/paths.d. Since I maintain my bash configuration I’ve decided to remove the entry /etc/paths.d (on any machine I find it) and rely upon the code in my bash_profile.

Conclusion

Here are my tips for keeping your path up to date and easy to work with.