Posted on Views: Waline: Word count in article: 1.6k Reading time ≈ 6 mins.

date: 2024-02-12
description: The author encountered problems when setting up a proxy in WSL2 (Ubuntu20.04), which led to an exploration of the differences between the .profile and .bashrc files in Linux. The author asked GPT4 - 32K, Tongyi Qianwen, and Wenxin Yiyan 4.0, compared the answers of each model, and pondered over the impact of large language models (LLMs) on engineers.
keywords: Linux, .profile file, .bashrc file, large language models (LLMs), Tongyi Qianwen, GPT4 - 32K, Wenxin Yiyan 4.0
tags:

  • Linux
  • chatgpt
    title: You Might Really Be Inferior to Large Language Models

I. Preface

Yesterday, I needed to set up a proxy in WSL2 (Ubuntu20.04). To have it automatically configured after startup, I wrote the proxy - setting commands into the .profile file. It worked when I connected to Ubuntu via MobaXterm. However, when VScode on Ubuntu tried to download something through the proxy, the proxy was found to be unavailable. I didn’t understand why, but then I tentatively wrote the proxy - setting commands into the .bashrc file, and it turned out that the proxy could be used in VScode.

To be honest, I’ve been dealing with Linux since I started working, and it’s been six years now. But I’ve never really delved into the differences between the .profile and .bashrc files.

So I decided to ask this question to large language models. I asked GPT4 - 32K, Tongyi Qianwen, and Wenxin Yiyan 4.0 at the same time. The following are the specific processes and results.

II. Role Setting of Large Language Models

I set the exact same role for each model, with the following prompt:

You are a Linux expert, proficient in Linux development, usage, and maintenance, and good at explaining Linux knowledge to others. Please complete the task I assign to you.

III. The Question

The question was also the same for all, as follows:

What are the differences and similarities between .profile and .bashrc in Linux? What are their respective functions?

IV. Answers

The answers from the three large language models are as follows:

1. GPT4 - 32K

Both .bashrc and .profile are scripts executed when a new bash shell is launched, but they differ in when they are executed and the scenarios in which they are applied.

  1. .bashrc: This file is mainly read by non - login shells. Whenever you open a new shell within an existing bash shell (for example, by opening a new terminal window through programs like “xterm” or “gnome - terminal”), .bashrc will be read and executed. Therefore, .bashrc is mainly used to contain settings such as aliases and functions that you want to apply in each new sub - shell.

  2. .profile: This file is only read once when you log in to the system (that is, when you enter your username and password to enter the system after startup, or when you switch users using “su - username”). Usually, .profile is used to contain commands that you want to execute only once at login, such as setting environment variables.

The similarity between the two is that they are both used to customize the user’s shell environment. The difference lies in the time and occasion of execution.

Developers can define corresponding content in these two files according to their needs. For example, if you want to define some aliases that are needed in all situations, you may choose to define them in the .bashrc file; while if you need to set some global environment variables, since environment variables are inherited in sub - shells, you may choose to set these variables in the .profile file.

2. Tongyi Qianwen

In the Linux environment, both the .profile and .bashrc files are used to configure the user’s shell environment, but their scopes of action and loading times are different.

.profile

  • Location: Usually, it is a hidden file in the user’s home directory (~/.profile).
  • Function:
    • .profile is a general configuration file for the Bourne Shell (including its derivatives such as sh and bash), used to set environment variables, aliases, and other startup items for the login shell.
    • When a user logs in through the terminal (i.e., a “login shell”), the system will automatically read and execute the commands in this file.
    • In a Bash - based system, .profile can set global environment variables that need to take effect when all types of shells are initialized, such as PATH, USER, HOME, etc.

.bashrc

  • Location: Also in the user’s home directory, it is a configuration file specifically designed for Bash (~/.bashrc).
  • Function:
    • .bashrc is a personalized configuration file for interactive non - login Bash shells.
    • When a user opens a new terminal window (non - login shell) or starts a new bash instance through an already - logged - in shell, .bashrc will be read and executed.
    • Here, users can define their own aliases, functions, Bash shell options, and other environment variables that are only needed in an interactive Bash session.

Similarities:

  • Both are text files containing a series of shell commands and environment variable settings.
  • Users can add custom logic in them to customize their working environment, such as color schemes, history size, PS1 prompt style, etc.

Summary:

  • .profile is mainly responsible for initializing the user’s entire desktop environment or command - line environment once when the system is logged in, with a wider scope of influence.
  • .bashrc is more focused on the personalized settings of a single interactive Bash shell. It is activated every time a new bash shell is launched, and is more commonly used for frequently used functions and personalized settings. At the same time, it is common to see commands in .bash_profile that call .bashrc to ensure that these personalized settings are also applied in the login shell.

3. Wenxin Yiyan 4.0

In Linux, .profile and .bashrc are two files commonly used to configure the user environment, but they have some differences and similarities in terms of usage timing, function, and loading method.

.profile

  • Location: Usually located in the user’s home directory, such as ~/.profile.
  • Loading Timing: When a user logs in, the system will execute this file. This means that whether it is through the console, graphical interface login, or remote SSH login, .profile will be executed.
  • Function: Usually used to set environment variables, PATH, and other configurations that only need to be done at login.
  • Precautions: Since it is only executed once at login, it is not suitable for placing commands that need to be executed frequently, such as alias or function definitions.

.bashrc

  • Location: Also located in the user’s home directory, such as ~/.bashrc.
  • Loading Timing: When a new bash shell is launched (whether it is a login shell or a non - login shell), .bashrc will be executed. This includes cases such as launching a sub - shell through the bash command, or logging in via SSH and requesting a non - login shell.
  • Function: Mainly used for the configuration of the bash shell, including defining aliases, functions, setting bash options, and configuring the command prompt (PS1).
  • Precautions: Since it is executed every time a bash shell is launched, time - consuming commands should be avoided.

Similarities

  • Both are text files used to configure the user environment.
  • They can both set environment variables, PATH, etc.
  • Both use the bash shell syntax.

Differences

  • Loading Timing: .profile is executed at login, while .bashrc is executed every time a bash shell is launched.
  • Purpose: .profile is more suitable for setting login - related environment variables, while .bashrc is more suitable for configuring the behavior and appearance of the bash shell.
  • Execution Frequency: .profile is only executed once when the user logs in, while .bashrc may be executed multiple times during the same session (each time a new bash shell is launched).

Practical Suggestions

  • If you want to set some environment variables or execute certain commands at login, and these settings or commands are valid throughout the session, you should put them in .profile.
  • If you want to configure the behavior of the bash shell (such as the command prompt, aliases, etc.), and these configurations need to take effect every time a new bash shell is launched, you should put them in .bashrc.
  • Sometimes, you may want to call .bashrc in .profile to share some configurations. This can be achieved by adding code similar to if [ -f ~/.bashrc ]; then . ~/.bashrc; fi in .profile. However, note that this may cause the commands in .bashrc to be executed multiple times in the login shell (if .bashrc has already been loaded in other ways). Therefore, careful consideration is needed when making such a decision.

V. Some Thoughts

As we can see, the answers from all the models are quite good. At least they are understandable, and later I searched for other materials to verify, and these descriptions are basically correct.

Considering that both Wenxin Yiyan 4.0 and GPT4 - 32K require payment to use, by comparison, Tongyi Qianwen is a relatively good choice.

In fact, I’ve started using Tongyi Qianwen more frequently in the past ten - odd days because the results are really good, it’s free, and the response speed is also quite good.

Having said all this, let’s go back to the title: You might really be inferior to large language models.

I’ve been working for more than six years, and I’m still not clear about this question. I also asked several more senior colleagues, and none of them could clearly explain the functions and differences between the .profile and .bashrc files. For this kind of question that doesn’t require thinking and judgment, pure knowledge - point - type content, humans may really be no match for large language models.

Although from the above examples, large language models seem very powerful, in the short term, I don’t think engineers need to worry about being replaced by large language models. However, engineers who don’t use large language models are likely to be replaced by those who can use and are good at using them.