You see, any directory in your users’s PATH is global. That means you can issue a command by simply entering the command – you do not have to enter the full path to the command. That is why you don’t always have to enter /usr/bin/ls and you can just enter ls.

In this article, we step back for a bit of Linux basics and learn how to add directories to your path.

See what’s already there

If you are curious to know what is already in your PATH you can do so by entering the command echo $PATH. You should see something like:

/usr/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

The above is pretty standard for a default Linux path. What you are seeing is global paths, each separated by a “:”. Any file in:

• /usr/bin
• /usr/local/sbin
• /usr/local/bin
• /usr/sbin
• /usr/bin
• /sbin
• /usr/games

will be global for the user.

Adding a new directory

There are three ways to add a new directory to your path. Let’s take a look at them individually. The first method only adds the new directory to the PATH temporarily. This is great for testing purposes, but know that the minute you log out that directory is removed from the users’ path.

Let’s say you have the directory ~/scripts that you want to add temporarily. To do this open up a terminal window and issue the command:

PATH=$PATH:/home/USERNAME/scripts

Where USERNAME is the actual name of the user you are using. Now if you issue the command echo $PATH that new directory will be listed. Log out and log in and issue that same command and the directory will be gone.

Now let’s say you want to make that addition permanent for the user. This was typically done in the users’ ~/.bash_profile file. You might notice that you don’t have such a file. Newer Ubuntu releases have opted for the ~/.profile file instead. I still prefer to create a ~/.bash_profile for these purposes.  So if you don’t have a ~/.bash_profile create one and open it. If you have a ~/.bash_profile open it. and add a line like:

PATH=”$HOME/bin:$PATH:/home/USER/scripts:”

Where USER is the actual user name.

You might think you would have to log out and log back in. You don’t. Just issue the command source .bash_profile and the changes will take effect.

You can also add this path to every users PATH by adding the same line to the /etc/profile. You probably won’t find a reference to PATH in that file. So what you have to do is add the following lines to the end of that file:
PATH=$PATH:/home/USER/scripts
export PATH
Where USER is the actual user name. Of course you probably don’t want to add a directory of one user to everyone’s PATH, so you might want to create a new directory (like /data/scripts) and add that the to /etc/profile. Once you are done save that and the next time someone logs in they will have that new directory in their PATH.

Final thoughts

Linux is all about flexibility. As you can see it is possible to really stretch the usability of your directory structure to make it work for you instead of against you. Adding directories to your PATH variable allows you to create scripts that can be run globally, and by anyone.

As a Linux user you can add directories to your $PATH. This is helpful when you don’t want to add a command to a directory in your $PATH but you want that command to be globally executable. Doing this is actually quite easy.

What is currently in your $PATH?

NOTE: This article applies only when you are using the Bash shell. To find out what directories are included in your current $PATH issue the command:

echo $PATH

You should see something like:

/usr/lib/qt-3.3/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/jlwallen/bin

Notice the /opt directory is missing. Often the /opt directory is a great place to “install” other applications for global use. But if this directory is not in your $PATH, you will always have to use the explicit path to call a command. With that in mind let’s add /opt.

.bash_profile

In order to add a directory you have to edit a file in your ~/ (home) directory. The .bash_profile file determines user specific environment and start up programs. This file also  checks for a .bashrc file for aliases and functions, but that has nothing to do with your $PATH.

There is one particular line you need to examine in your .bash_profile:

PATH=$PATH:$HOME/bin

This is the line that determines anything extra in your $PATH. As you can see, in the example above, the extra directory added to the users’ $PATH is the ~/bin directory. Of course in most distributions this isn’t used (or even created during installation). Why ~/bin is still included I do not know. In order to add another directory to your $PATH in this line you would seperate the directories with a “:”. To add the /opt directory that line would now look like:

PATH=$PATH:$HOME/bin:/opt

As you can see the /opt directory has been added proceeding a “:”. Complete this addition and save the file. You’re not done yet.

If you issue the command echo $PATH you will still not see /opt in the users’ $PATH. Why? You have to log out and log back in before this change will take effect. So log out, log back in, and issue the command again. Issuing the command echo $PATH will not issue:

/usr/lib/qt-3.3/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/jlwallen/bin:/opt

Any command found in the /opt directory is now global.

Final thoughts

The $PATH is a very powerful tool to take advantage of in Linux. By using it you can install applications in directories outside of the norm and still make them global. I often install applications in the /opt directory or will create a /data directory for a more temporary application installation.