MAC OS uses /etc/paths file and /etc/paths.d directory for setting up the value of PATH env varialb.e. A utility path_helper is used to set the PATH env variable based on the content of /etc/paths file and content of files in /etc/paths.d directory. This is how you can run the path_helper
eval `/usr/libexec/path_helper -s`Let’s see how these two play role in setting up the path
/etc/paths file
This file contains the paths that need to be set in PATH env variable. If I print the contents of this file on my MAC, it outputs
/ $ cat /etc/paths
/usr/local/bin
/usr/bin
/bin
/usr/sbin
/sbinAll the above paths are added to the PATH variable.
/etc/paths.d directory
This directory contains the list of files. Each of the files contains the path that needs to be added to the PATH variable. As a demonstration, If I install GO on my MAC using the .pkg installer for GO available here – https://golang.org/dl/.
Then after installation, it will create a file named ‘go’ in the ‘/etc/paths.d’ directory. Let’s output the contents of the file.
/ $ cat /etc/paths.d/go
/usr/local/go/binIt outputs ‘/usr/local/go/bin’ and this path will be added to the PATH env variable.
Points to Note:
The primary reason that ‘/etc/paths.d’ directory is used because ‘/etc/paths’ will be modified and/or replaced by system upgrades while contents of ‘/etc/paths.d’ directory will never be affected by such changes.