How to create files with sudo so that the files is owned by root?

Question

I just confused to create file with sudo command. As i know, sudo command is commonly used for root privilege(by default) and when i created files using command below:

sudo cat > root.txt

And i saw the user, it still regular username not root. How that can be happen? and how to create files owned by root without changing user to root?

No not root privileges. Admin privileges. root is just another admin. " and how to create files owned by root without changing user to root?" you do realize this is 1 way? you can then do nothing with the file unless "others" has executable rights on the file? — Rinzwind, Sep 29 '20 at 12:46
It's because your unprivileged shell creates `root.txt`, then runs `cat` with `sudo`. See related [How to solve “permission denied” when using sudo with redirection in Bash?](https://askubuntu.com/questions/230476/how-to-solve-permission-denied-when-using-sudo-with-redirection-in-bash) — steeldriver, Sep 29 '20 at 12:49

score 4 · Answer 1 · answered Sep 29 '20 at 12:48

4

Redirection is 'outside' of sudo in your example. Try

sudo bash -c "cat > root.txt"

answered Sep 29 '20 at 12:48

sudodus

45,126
5
87
151

3

... or simply `sudo touch root.txt`, which avoids redirection altogether – steeldriver Sep 29 '20 at 12:50

score 2 · Accepted Answer · answered Sep 29 '20 at 12:54

2

Stream redirection (> file) takes place in the parent process (running as $USER) before the command (sudo) even begins.

You can either use a different command:

sudo tee root.txt

or, afterwards, change the ownership of the file:

sudo chown root:root root.txt

answered Sep 29 '20 at 12:54

waltinator

35,099
19
57
93

1

You'd need something like `: | sudo tee filename` else `tee` will block waiting for input – steeldriver Sep 29 '20 at 12:55

How to create files with sudo so that the files is owned by root?

2 Answers2