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Q&A

Why does Linux use the sudo command?

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Why does Linux use the sudo command?

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Very vague question (1 comment)

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In Unix systems like Linux, some commands are considered dangerous and only the root user can run them. Normally, you don't login as root. So when you want to run dangerous commands, you must first become root. Then you run your dangerous stuff, and go back to your own user.

This switching between users is tedious and many people don't like it. So the sudo command was created to automate the process. sudo some_command is equivalent to:

1. Log out
2. Log in as root
3. Run some_command
4. Log out
5. Log in as your normal user

But it is nicer because it inherits most of your user environment. For example, sudo ls ~ is smart enough to print the contents of your actual home directory, instead of the root's home directory. This is because logging in as root would set environment variables like $HOME to root's home (/root), but sudo doesn't use the normal interactive login and does not change your $HOME from the value corresponding to your normal user. There are many other small details like this that sudo avoids for you.

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`sudo ls ~` will not tell you whether `sudo` sets `HOME`, because the `~` is expanded by the non-root... (2 comments)

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