Solving the ‘Command Not Found’ Error on Linux

While using the terminal of your Linux system, you will receive the Command Not Found error whenever a command you are entering is not accessible. In most cases, this could be due to a simple typo, or it could mean that you do not have the command installed yet. It could also indicate that the command is just missing from your system’s PATH environment variable, which is another easy thing to fix.

In this tutorial, we will show you how to fix the Command Not Found error on Linux. We will go over the most common issues that cause this error, and cover the steps necessary to implement a solution that remedies the problem. Follow along with us below to find out what is causing the error to occur and how to fix it.

In this tutorial you will learn:

• How to install a command if it is missing
• How to check the whole path to a command’s executable
• How to add a command’s directory to PATH environment variable
• How to add executable permissions to a command

Software Requirements and Linux Command Line Conventions

Category	Requirements, Conventions or Software Version Used
System	Any Linux distro
Software	N/A
Other	Privileged access to your Linux system as root or via the sudo command.
Conventions	# – requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command $ – requires given linux commands to be executed as a regular non-privileged user

Solving the ‘Command Not Found’ Error on Linux – Troubleshooting Methods

---

---

Since there are various issues that could be causing the error to occur, we will run through some steps to troubleshoot it below. We will start with the simplest solutions, and graduate to more in depth problem fixing if the error persists.

1. Although your Linux system comes with a lot of basic commands by default, a lot more can be installed to extend the functionality of your system. If you are getting the Command Not Found error, consider that the requisite package may not be installed.

   $ curl
   Command 'curl' not found, but can be installed with:
   sudo snap install curl  # version 7.87.0, or
   sudo apt  install curl  # version 7.81.0-1ubuntu1.7
   

   As you can see in the output above, when running the curl command on our system, we receive the error but also get some suggestions about how to install it so we can use it. Your terminal may or may not give you package suggestions if a command is missing. A quick internet search will tell you how to install the command that you are missing.

2. If you are sure that the command is installed, but you still receive the same error, then use the which command to check if the executable file is stored in your PATH environment variable. As an example, we will check the full path to the curl command:

   $ which curl
   

3. If the which command returns some output, then it is possible that your current user does not have executable permissions on the command’s binary file. You could change the permissions with the following command. Substitute the example path below with the actual path to your command’s binary:

   $ chmod +x /usr/bin/curl
   

4. If the output from the which command is blank, then the executable file’s directory needs to be added to the PATH environment variable. Check your currently configured directories with this command:
   

   ---

   ---

   $ echo $PATH
   

5. To add a directory to $PATH permanently, we’ll need to edit the .bashrc file of the user you want to change. Use nano or your favorite text editor to open the file, stored in the home directory.

   $ nano ~/.bashrc
   

6. At the end of this file, put your new directory that you wish to permanently add to $PATH. Note that /path/to/curl is just an example below, and you should replace that directory with the one where your command is actually stored.

   export PATH="/path/to/curl:$PATH"
   

7. Save your changes and exit the file. Afterwards, execute the following command to make the changes take effect in your current session. Alternatively, you can log out or reboot the system.

   $ source ~/.bashrc
   

Closing Thoughts

---

---

In this tutorial, we saw how to troubleshoot the Command Not Found error on a Linux system. Every user will eventually encounter this error because of typos or because the command they need is not installed by default. This is an easy fix as the vast majority of commands you will use can be installed via your system package manager. You may also encounter the error if your command’s directory has not yet been added to PATH, but this is another easy fix as we saw in the steps above.