How do I use sudo to redirect output to a location I don't have permission to write to?

Question

I\'ve been given sudo access on one of our development RedHat linux boxes, and I seem to find myself quite often needing to redirect output to a location I don\'t normally h

Answer 1

sudo at now  
at> echo test > /tmp/test.out  
at> <EOT>  
job 1 at Thu Sep 21 10:49:00 2017  

Answer 2

Your command does not work because the redirection is performed by your shell which does not have the permission to write to /root/test.out. The redirection of the output is not performed by sudo.

There are multiple solutions:

• Run a shell with sudo and give the command to it by using the -c option:

  sudo sh -c 'ls -hal /root/ > /root/test.out'
  

• Create a script with your commands and run that script with sudo:

  #!/bin/sh
  ls -hal /root/ > /root/test.out
  

  Run sudo ls.sh. See Steve Bennett's answer if you don't want to create a temporary file.

• Launch a shell with sudo -s then run your commands:

  [nobody@so]$ sudo -s
  [root@so]# ls -hal /root/ > /root/test.out
  [root@so]# ^D
  [nobody@so]$
  

• Use sudo tee (if you have to escape a lot when using the -c option):

  sudo ls -hal /root/ | sudo tee /root/test.out > /dev/null
  

  The redirect to /dev/null is needed to stop tee from outputting to the screen. To append instead of overwriting the output file (>>), use tee -a or tee --append (the last one is specific to GNU coreutils).

Thanks go to Jd, Adam J. Forster and Johnathan for the second, third and fourth solutions.

Answer 3

How about writing a script?

Filename: myscript

#!/bin/sh

/bin/ls -lah /root > /root/test.out

# end script

Then use sudo to run the script:

sudo ./myscript

Answer 4

I would do it this way:

sudo su -c 'ls -hal /root/ > /root/test.out'

Answer 5

The way I would go about this issue is:

If you need to write/replace the file:

echo "some text" | sudo tee /path/to/file

If you need to append to the file:

echo "some text" | sudo tee -a /path/to/file

Answer 6

Don't mean to beat a dead horse, but there are too many answers here that use tee, which means you have to redirect stdout to /dev/null unless you want to see a copy on the screen.

A simpler solution is to just use cat like this:

sudo ls -hal /root/ | sudo bash -c "cat > /root/test.out"

Notice how the redirection is put inside quotes so that it is evaluated by a shell started by sudo instead of the one running it.