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Asked: 2024-09-25T17:41:11+05:30 In:

What are the distinctions between using echo and export when setting an environment variable in a Linux system?

I’ve been diving into the world of Linux recently, and I’ve stumbled upon something that’s got me scratching my head. You know how we often need to set environment variables for different applications or scripts? Well, I came across two common methods to do this: using `echo` and using `export`. I thought I understood the basics, but after some testing, I’m not so sure anymore.

Let’s say I want to set an environment variable called `MY_VAR` to hold a simple string value like “HelloWorld.” I tried doing it with `echo` first. I did something like:

“`bash
echo MY_VAR=”HelloWorld”
“`

And I thought, “Hey, this is simple enough!” But then later, when I checked for the variable using `echo $MY_VAR` in the same terminal session, nothing showed up. So it got me thinking: does `echo` really set the variable, or is it just printing something to the screen?

Then I moved on to `export` and tried:

“`bash
export MY_VAR=”HelloWorld”
“`

This definitely felt more official, and when I checked afterward, `echo $MY_VAR` returned “HelloWorld” like I expected. It seemed like `export` was the key to making the variable accessible in my current session.

So here’s where I’m scratching my head: what’s the real difference in using `echo` vs. `export`? I get that `export` makes it accessible to child processes, but isn’t there some nuance I’m missing? Is there a case where `echo` could be useful in this context or is it entirely redundant for setting variables?

I’d love to hear what other people think! Am I just overcomplicating things here, or is there something deeper about how these commands function? Would really appreciate any insights, especially from those who’ve been working with Linux for a while!

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    2 Answers



    1. Understanding Environment Variables in Linux

      Environment Variables in Linux: echo vs export

      You’re totally correct in your observations about echo and export. It can definitely get a bit tricky when you’re just starting out with Linux environment variables!

      When you use echo MY_VAR="HelloWorld", what you’re actually doing is merely printing that string to the terminal. It doesn’t set the variable at all. In other words, it’s just a display command. If you want to see something displayed on the screen, great! But it won’t affect the environment variables in your shell session.

      On the other hand, when you use export MY_VAR="HelloWorld", you’re actually creating an environment variable named MY_VAR and defining its value as HelloWorld. This variable is now part of your shell’s environment and can be accessed by any subprocess that you start from this shell. That’s why when you run echo $MY_VAR afterward, it outputs HelloWorld.

      So to sum it up:

      • echo is for displaying text; it doesn’t set or alter any variables.
      • export is what you want to use to create environment variables and make them available to your current session and child processes.

      As for your question about usefulness: echo can be helpful for debugging or checking values that you’ve already set. For example, if you’re looking to see the value of a variable, using echo is a quick way to do that. Just remember, it won’t set a variable for you.

      You’re definitely not overcomplicating things—it’s a common point of confusion! The distinctions between these commands are important as you dig deeper into scripting and automation on Linux.

      Keep experimenting and asking questions like this. It’s the best way to learn!


    2. When it comes to setting environment variables in Linux, there’s a significant distinction between using `echo` and using `export`. The command `echo MY_VAR=”HelloWorld”` simply prints the string `MY_VAR=”HelloWorld”` to the terminal, but it does not set any variable in the current session. The output of an `echo` command is just that—an output. If you want to set an environment variable, you must use the assignment syntax without any additional commands. So simply typing `MY_VAR=”HelloWorld”` alone (without `echo` and without `export`) would create a local variable only accessible to your current shell processes, but it wouldn’t survive across subshells, i.e., it would not be available in processes spawned after the variable’s creation.

      On the other hand, the command `export MY_VAR=”HelloWorld”` does two things: it assigns the string “HelloWorld” to `MY_VAR` and marks it for export, meaning that it will be inherited by any child processes spawned from your current shell. This is important if you need the variable to be accessible by scripts or programs that you may run in that session. In summary, while `echo` is useful for printing or debugging without affecting your shell’s environment, `export` is critical for establishing environment variables that child processes can access. Understanding this distinction is key to effectively managing environment variables in your Linux environment.

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