# Environment Variables — Linux

Source: https://www.geekswithgeeks.com/en/linux/linux-env-vars

> Named values every process can read.

## What an env var is

An **environment variable** is a named value available to a shell and the processes it starts — used for config like `EDITOR`, `HOME`, or `PATH`.

## export & echo

`export` sets a variable and makes it visible to child processes; `$VAR` reads it back.

```bash
export EDITOR=vim
echo $EDITOR
env | grep EDITOR
```

Output:

```
vim
EDITOR=vim
```

## .bashrc vs .profile

`~/.bashrc` runs for every new interactive shell; `~/.profile` runs once at login. Put persistent `export` lines there so they survive a restart.