What Is This $Path in Linux and How to Modify It

What is this $PATH in Linux and how to modify it

To get your path current $PATH variable type in:

echo $PATH 

It tells your shell where to look for binaries.

Yes, you can change it - for example add to the $PATH folder with your custom scripts.

So: if your scripts are in /usr/local/myscripts to execute them you will have to type in a full path to the script: /usr/local/myscripts/myscript.sh
After changing your $PATH variable you can just type in myscript.sh to execute script.

Here is an example of $PATH from RHEL:

/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/home/user/bin

To change your $PATH you have to either edit ~/.profile (or ~/.bash_profile) for user or global $PATH setting in /etc/profile.

One of the consequences of having inaccurate $PATH variables is that shell will not be able to find and execute programs without a full $PATH.

How can I edit the $PATH on linux?

To permanently store your path, you have a few options.

I suggest you read the Ubuntu community wiki on Environment Variables but the short answer is the best place is ~/.profile for your per-user PATH setting or /etc/profile for global settings.

Change PATH:

1. Append something to your PATH

   export PATH=$PATH:/your/new/path/here
   

2. Override your PATH (save backup before!)

   export PATH=:/your/new/path/here:/another/new/path/here
   

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?

Where is PATH variable set in Ubuntu?

Grzegorz Żur's answer to another question captures it brilliantly. Unfortunately it was hidden away among many other answers.

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.

System wide

1. /etc/environment List of unique assignments. Perfect for adding system-wide directories like /usr/local/something/bin to PATH
   variable or defining JAVA_HOME.
2. /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.
3. /etc/profile and /etc/profile.d/* Shell script. This is a good choice for shell-only systems. Those files are read only by shells.
4. /etc/<shell>.<shell>rc. Shell script. This is a poor choice because it is single shell specific.

Also, /etc/environment is not a script file, but rather consists of assignment expressions, one per line. Since this file stores the system-wide locale and path settings, it is most oft quoted choice.
Using /etc/profile is not preferred. It exists only to point to /etc/bash.bashrc and to collect entries from /etc/profile.d

User session

1. ~/.pam_environment. List of unique assignments. 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 variable
   including HOME or PATH so it has limited use.
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 script. It will be visible only for programs started from terminal or terminal emulator. It is a good choice for
   shell-only systems.
4. ~/.<shell>rc. Shell script. This is a poor choice because it is single shell specific.

How do I change the order of $PATH?

You can set your PATH in the file .bash_profile, which is in your home directory.

More specifically, you can simply add the following line to the end of that file

export PATH=/usr/local/bin:$PATH

This results in /usr/local/bin being prepended to the existing PATH. In other words, the folder /usr/local/bin is inserted in front of your PATH, and so it would have the highest priority. You can also append a folder to your path by doing

export PATH=$PATH:/usr/local/bin

In general, you can set the order of the folders or files that you export in a similar way as the following:

export PATH=/usr/local/bin:/Applications/Sublime Text 2.app/Contents/SharedSupport/bin:/Users/pathreskoo/anaconda/bin:/Library/Frameworks/Python.framework/Versions/2.7/bin:/opt/local/bin:/opt/local/sbin:/Library/Frameworks/Python.framework/Versions/2.7/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin:/usr/local/git/bin

Note: this is not the only place you can set the PATH, but it is a common one.

Remove redundant paths from $PATH variable

You just execute:

export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

that would be for the current session, if you want to change permanently add it to any .bashrc, bash.bashrc, /etc/profile - whatever fits your system and user needs.

Note: This is for Linux. We'll make this clear for new coders. (` , ') Don't try to SET = these.

How to Permanently update PATH variable in Unix

If this is for all users, place this in /etc/profile or /etc/bashrc
If just for a given user, place it in his/her ~/.bashrc.

I hope this helps.

How to modify the apktool path

If you follow the steps to install apktool:
https://ibotpeaches.github.io/Apktool/install/

You will notice there are 2 files you need:

1. a script (the one you posted), which you should name apktool and set to executable on linux chmod +x apktool
2. a jar file: apktool.jar

You need to have both files in the same directory for the script to work, so if you've moved the apktool file to /usr/share/apktool, you need to also move apktool.jar to /usr/share/apktool.jar

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