bashrc vs. bash_profile What Is Difference

If you're new to command line interface, you may have come across terms bashrc and bash_profile. These are important files that can be found in your home directory and are used to customize your shell environment. However, many users are often confused about differences between these two files. In this article, we'll dive into differences between bashrc and bash_profile, and explain how they work.

What is Bashrc?

Bashrc is a configuration file for Bash shell, which is default shell on most Linux distributions and macOS. This file is executed each time you open a new terminal window, and it contains commands that are executed in your shell environment. Bashrc is used to set environment variables, define aliases, and create functions. It's also used to customize prompt that appears in your terminal.

What is bash_profile?

Bash_profile is another configuration file for Bash shell, but it's executed only once when you log in to your account. This file is used to set environment variables and to run commands that are needed only once at start of your session. Bash_profile is commonly used to set PATH variable, which is an environment variable that determines where shell searches for executables.

What's Difference Between bashrc and bash_profile?

Bashrc and bash_profile serve similar functions, but they have different scopes and are executed at different times.

Execution Time

Bashrc is executed each time you open a new terminal window, while bash_profile is executed only once when you log in to your account. This means that any changes you make to bashrc will take effect immediately, while changes to bash_profile will take effect only when you log out and log back in again.

Scope

Bashrc is used to customize your shell environment for each individual terminal window. This means that any changes you make to bashrc will affect only current terminal window. On other hand, bash_profile is used to set environment variables that are needed for entire session. This means that changes to bash_profile will affect all terminal windows.

Common Usage

Bashrc is commonly used to set aliases, define functions, and customize prompt. Bash_profile is commonly used to set PATH variable and to run commands that are needed only once at start of your session.

Examples

Here are a few examples to illustrate differences between bashrc and bash_profile −

Example 1: Setting Aliases

Suppose you want to set an alias for ls command to list files in long format. You can do this by adding following line to your bashrc file −

alias ll='ls -l'

This will create an alias ll that you can use instead of ls -l to list files in long format. However, if you want this alias to be available for all terminal windows, you should add this line to your bash_profile file instead.

Example 2: Setting PATH Variable

Suppose you have installed a custom application in your home directory, and you want to add its location to your PATH variable so that you can run it from anywhere in your shell. You can do this by adding following line to your bash_profile file −

export PATH=$PATH:/home/user/myapp/bin

This will add /home/user/myapp/bin to PATH variable, so that you can run application from anywhere in your shell.

Example 3: Customizing Prompt

Suppose you want to customize prompt that appears in your terminal window to include current date and time. You can do this by adding following line to your bashrc file −

export PS1='\u@\h \D{%F %T} \w\$ '

This will customize prompt to display username, hostname, date and time, and current working directory. However, this customization will only apply to current terminal window. If you want to customize prompt for all terminal windows, you should add this line to your bash_profile file instead.

Additional Tips to Work with bashrc and bash_profile

Check Your Shell Environment

To check your current shell environment, you can use echo command to print value of SHELL variable. For example, to check if you're using Bash, run following command in your terminal −

echo $SHELL

This should output path to Bash shell, which is usually /bin/bash.

Edit Files with a Text Editor

You can edit bashrc and bash_profile files with any text editor, such as nano or vim. These files are located in your home directory, and you can access them by typing following command in your terminal −

nano ~/.bashrc

This will open bashrc file in nano text editor, where you can make any changes you need. Similarly, you can open bash_profile file with following command −

nano ~/.bash_profile

Use Source Command

After making changes to your bashrc or bash_profile file, you need to reload changes in your current shell environment. To do this, you can use source command. For example, to reload your bashrc file, run following command in your terminal −

source ~/.bashrc

This will reload changes in your current terminal window. Similarly, you can reload your bash_profile file with following command −

source ~/.bash_profile

Be Careful with Syntax Errors

When editing your bashrc or bash_profile files, be careful with syntax errors. Even a small mistake, such as a missing quotation mark or a misplaced semicolon, can cause your shell environment to behave unexpectedly or not work at all. To avoid syntax errors, it's a good idea to test your changes in a separate terminal window before applying them to your main environment.

Keep Your Files Organized

As you add more commands and customizations to your bashrc and bash_profile files, they can quickly become cluttered and difficult to manage. To keep your files organized, consider grouping related commands together and using comments to label different sections.

For example, you could create a section in your bashrc file for aliases, another for functions, and another for prompt customizations. Similarly, you could use comments to label each section and explain what each command does.

Back up Your Files

Your bashrc and bash_profile files are important system files that contain critical configuration information for your shell environment. To avoid accidentally deleting or corrupting these files, it's a good idea to back them up regularly.

You can create backups of your files by copying them to a separate directory or by using a version control system like Git. This way, if anything goes wrong, you can easily restore your files to their previous state.

Use System-wide Bashrc File

In addition to your personal bashrc and bash_profile files, your system may also have a global bashrc file that applies to all users. On Linux systems, this file is usually located in /etc/bashrc, while on macOS it's located in /etc/bashrc_Apple_Terminal.

The system-wide bashrc file is a good place to add commands and customizations that apply to all users on system, such as system-wide aliases or environment variables. Just be aware that changes to this file will affect all users on system, so use caution when making changes.

Be Mindful of Security

Your bashrc and bash_profile files can contain sensitive information, such as passwords, API keys, or other credentials. To protect this information, be mindful of security best practices, such as keeping your files private, using strong passwords, and avoiding storing sensitive information in plain text.

If you need to store sensitive information in your shell environment, consider using a password manager or encrypted file to protect your data. Alternatively, you can use environment variables to store sensitive information, which are not stored in your files and can be encrypted or secured separately.

Conclusion

In summary, bashrc and bash_profile are both important configuration files for Bash shell. Bashrc is executed each time you open a new terminal window and is used to customize your shell environment for each individual terminal window. Bash_profile, on other hand, is executed only once when you log in to your account and is used to set environment variables and to run commands that are needed only once at start of your session.

Understanding differences between these two files is important for customizing your shell environment and ensuring that your changes take effect when and where you want them to. By using these files effectively, you can create a customized and efficient shell environment that suits your needs.