Adding a Directory to Path in Ubuntu

How to permanently set $PATH on Linux/Unix

There are multiple ways to do it. The actual solution depends on the purpose.

The variable values are usually stored in either a list of assignments or a shell script that is run at the start of the system or user session. In case of the shell script you must use a specific shell syntax and export or set commands.

System wide

1. /etc/environment List of unique assignments. Allows references. Perfect for adding system-wide directories like /usr/local/something/bin to PATH variable or defining JAVA_HOME. Used by PAM and systemd.

2. /etc/environment.d/*.conf List of unique assignments. Allows references. Perfect for adding system-wide directories like /usr/local/something/bin to PATH variable or defining JAVA_HOME. The configuration can be split into multiple files, usually one per each tool (Java, Go, and Node.js). Used by systemd that by design do not pass those values to user login shells.

3. /etc/xprofile Shell script executed while starting X Window System session. This is run for every user that logs into X Window System. It is a good choice for PATH entries that are valid for every user like /usr/local/something/bin. The file is included by other script so use POSIX shell syntax not the syntax of your user shell.

4. /etc/profile and /etc/profile.d/* Shell script. This is a good choice for shell-only systems. Those files are read only by shells in login mode.

5. /etc/<shell>.<shell>rc. Shell script. This is a poor choice because it is single shell specific. Used in non-login mode.

User session

1. ~/.pam_environment. List of unique assignments, no references allowed. Loaded by PAM at the start of every user session irrelevant if it is an X Window System session or shell. You cannot reference other variables including HOME or PATH so it has limited use. Used by PAM.

2. ~/.xprofile Shell script. This is executed when the user logs into X Window System system. The variables defined here are visible to every X application. Perfect choice for extending PATH with values such as ~/bin or ~/go/bin or defining user specific GOPATH or NPM_HOME. The file is included by other script so use POSIX shell syntax not the syntax of your user shell. Your graphical text editor or IDE started by shortcut will see those values.

3. ~/.profile, ~/.<shell>_profile, ~/.<shell>_login Shell script. It will be visible only for programs started from terminal or terminal emulator. It is a good choice for shell-only systems. Used by shells in login mode.

4. ~/.<shell>rc. Shell script. This is a poor choice because it is single shell specific. Used by shells in non-login mode.

Notes

GNOME on Wayland starts a user login shell to get the environment. It effectively uses the login shell configurations ~/.profile, ~/.<shell>_profile, ~/.<shell>_login files.

Man pages

• environment
• environment.d https://linux.die.net/man/1/environment.d
• bash
• dash

Distribution-specific documentation

• Ubuntu
• Arch Linux

Related

Difference between Login Shell and Non-Login Shell?

Add directory to path globally on ubuntu server

You could add the following in /etc/bashrc

export PATH="$PATH:/your/directory"

How to set PATH in Ubuntu 17.10 for custom path

The user bin directory should already be added to your path by the ~/.profile script.

# set PATH so it includes user's private bin directories
PATH="$HOME/bin:$HOME/.local/bin:$PATH"

Did you add the export line to your ~/.bashrc file?

export PATH="$HOME/bin:$PATH"

Permanently add a directory to PYTHONPATH?

You need to add your new directory to the environment variable PYTHONPATH, separated by a colon from previous contents thereof. In any form of Unix, you can do that in a startup script appropriate to whatever shell you're using (.profile or whatever, depending on your favorite shell) with a command which, again, depends on the shell in question; in Windows, you can do it through the system GUI for the purpose.

superuser.com may be a better place to ask further, i.e. for more details if you need specifics about how to enrich an environment variable in your chosen platform and shell, since it's not really a programming question per se.

How to set an environment variable to point to a location and how to set path of an environment variable in UBUNTU?

Yes, the above command sets variable when executing together with other commands like so:

$ VAR1=/home/folder1/lib123.so MY_AWESOME_COMMAND

Or you can use export so that you won't have to include the variable in each command.

$ export VAR1=/home/folder1/lib123.so

Test it below:

$ echo $VAR1
$ /home/folder1/lib123.so

What does it mean to add a directory to your PATH?

Adding a directory to your PATH expands the # of directories that are searched when, from any directory, you enter a command in the shell.

See http://www.linfo.org/path_env_var.html for more: "A user's PATH consists of a series of colon-separated absolute paths that are stored in plain text files. Whenever a user types in a command at the command line that is not built into the shell or that does not include its absolute path and then presses the Enter key, the shell searches through those directories, which constitute the user's search path, until it finds an executable file with that name."

Ubuntu add directory to Python path

Create a .bash_profile in your home directory. Then, add the line

PYTHONPATH=$PYTHONPATH:new_dir
EXPORT $PYTHONPATH

Or even better:

if [ -d "new_dir" ] ; then
  PYTHONPATH="$PYTHONPATH:new_dir"
fi
EXPORT $PYTHONPATH

The .bash_profile properties are loaded every time you log in.

The source command is useful if you don't want to log in again.

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