Permission denied when trying to append a file to a root owned file with sudo [closed]

Answer 1

try

sudo bash -c 'cat add_file >> /etc/file'

or

cat add_file | sudo tee -a /etc/file > /dev/null

Answer 2

Try doing this instead :

sudo tee -a /etc/file < add_file

It's lighter than running bash or sh -c command

Answer 3

Similar approach to @gniourf_gniourf answer, but using ex:

sudo ex +"r in.txt" -cwq out.txt

which is equivalent to vi/vim Ex-mode (-e).

This in-place edit example is simple, safe and convenient approach, because it doesn't use any shell piping, FIFOs or shell within the shell workarounds.

To boost performance for scripting purposes, consider using silence mode (-s).

Answer 4

You are trying to write the result of the command sudo cat add_file to the file /etc/file. And apparently you don't have that right.

man sudo gives that example :

   To make a usage listing of the directories in the /home partition.  Note
   that this runs the commands in a sub-shell to make the cd and file
   redirection work.

    $ sudo sh -c "cd /home ; du -s * | sort -rn > USAGE"

So you should try :

sudo sh -c "cat add_file >> /etc/file"

Answer 5

Run bash as sudo:

$ sudo bash -c "cat add_file >> /etc/file"

$ whoami;sudo bash -c "whoami";whoami
iiSeymour
root
iiSeymour

Answer 6

A funny possibility is to use ed (the standard editor):

sudo ed -s /etc/file <<< $'r add_file\nwq'

I know I won't get upvoted for this wonderful answer, but I wanted to include it here anyway (because it's funny). Done!