understand-and-edit-path-content.md

Understand and edit $PATH content

In order to find out where the system will look for binaries we need to check the content of the $PATH environment variable. We can specify a set of directories where executable programs are located using $PATH. The $PATH variable is specified as a list of directory names separated by colon : characters:

$ echo "$PATH"
/Users/albertmata/anaconda/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin:/usr/local/share/dotnet:/Library/TeX/texbin

Some of these entries are common stuff that comes by default, while some others come from software I have installed (and allowed to modify my $PATH variable). For instance, that first entry /Users/albertmata/anaconda/bin comes from file ~/.bash_profile, which in my case contains this:

$ cat ~/.bash_profile
[[ -s "$HOME/.profile" ]] && source "$HOME/.profile" # Load the default .profile
# added by Anaconda2 4.4.0 installer
export PATH="/Users/albertmata/anaconda/bin:$PATH"

And the last three entries /opt/X11/bin:/usr/local/share/dotnet:/Library/TeX/texbin do exist because my /etc/paths.d directory contains three text files with those three paths:

$ pwd
/etc/paths.d
$ ls
40-XQuartz	TeX		dotnet
$ cat 40-XQuartz 
/opt/X11/bin

So, in short, if we want to add a new path to $PATH so the system looks for binaries there we can either:

• Edit the ~/.bash_profile to add a new export line (if we need to generate the $PATH variable for a single user account), or...
• Add a new file to /etc/paths.d directory (if we want to generate the $PATH variable for all user accounts on the system).