insert text in a file using echo command

Question

I am trying to insert some text in a file in the following way

sudo echo "abc-abc/abc/abc" >> /etc/portage/make.conf

but it give me the error Permission denied

although I am using sudo command

Answer 1

In that command line, your shell opens the /etc/portage/make.conf in append mode, makes it the stdout of a new process and runs sudo in that new process. It's not sudo nor echo that open the file, it's your shell which is running with your credentials.

You'd need the file to be opened by the command started as root. So it could be:

sudo sh -c 'echo "abc-abc/abc/abc" >> /etc/portage/make.conf'

Or:

echo "abc-abc/abc/abc" | sudo tee -a /etc/portage/make.conf > /dev/null

Answer 2

Sudo just executes the first command, in your case " echo "abc-abc/abc/abc" ".

So the rest of the command (writing in /etc/portage/make.conf) will be executed in user mode.

You just have to modify the permissions on the file using chmod.