sudo echo "something" >> /etc/privilegedFile doesn't work

Bash Problem Overview

This is a pretty simple question, at least it seems like it should be, about sudo permissions in Linux.

There are a lot of times when I just want to append something to /etc/hosts or a similar file but end up not being able to because both > and >> are not allowed, even with root.

Is there someway to make this work without having to su or sudo su into root?

Bash Solutions

Solution 1 - Bash

Use tee --append or tee -a.

echo 'deb blah ... blah' | sudo tee -a /etc/apt/sources.list

Make sure to avoid quotes inside quotes.

To avoid printing data back to the console, redirect the output to /dev/null.

echo 'deb blah ... blah' | sudo tee -a /etc/apt/sources.list > /dev/null

Remember about the (-a/--append) flag! Just tee works like > and will overwrite your file. tee -a works like >> and will write at the end of the file.

Solution 2 - Bash

The problem is that the shell does output redirection, not sudo or echo, so this is being done as your regular user.

Try the following code snippet:

sudo sh -c "echo 'something' >> /etc/privilegedfile"

Solution 3 - Bash

The issue is that it's your shell that handles redirection; it's trying to open the file with your permissions not those of the process you're running under sudo.

Use something like this, perhaps:

sudo sh -c "echo 'something' >> /etc/privilegedFile"

Solution 4 - Bash

sudo sh -c "echo 127.0.0.1 localhost >> /etc/hosts"

Solution 5 - Bash

Doing

sudo sh -c "echo >> somefile"

should work. The problem is that > and >> are handled by your shell, not by the "sudoed" command, so the permissions are your ones, not the ones of the user you are "sudoing" into.

Solution 6 - Bash

I would note, for the curious, that you can also quote a heredoc (for large blocks):

sudo bash -c "cat <<EOIPFW >> /etc/ipfw.conf
<?xml version=\"1.0\" encoding=\"UTF-8\"?>
 
<plist version=\"1.0\">
  <dict>
    <key>Label</key>
    <string>com.company.ipfw</string>
    <key>Program</key>
    <string>/sbin/ipfw</string>
    <key>ProgramArguments</key>
    <array>
      <string>/sbin/ipfw</string>
      <string>-q</string>
      <string>/etc/ipfw.conf</string>
    </array>
    <key>RunAtLoad</key>
    <true></true>
  </dict>
</plist>
EOIPFW"

Solution 7 - Bash

In bash you can use tee in combination with > /dev/null to keep stdout clean.

 echo "# comment" |  sudo tee -a /etc/hosts > /dev/null

Solution 8 - Bash

Some user not know solution when using multiples lines.

sudo tee -a  /path/file/to/create_with_text > /dev/null <<EOT 
line 1
line 2
line 3
EOT

Solution 9 - Bash

Using Yoo's answer, put this in your ~/.bashrc:

sudoe() {
    [[ "$#" -ne 2 ]] && echo "Usage: sudoe <text> <file>" && return 1
    echo "$1" | sudo tee --append "$2" > /dev/null
}

Now you can run sudoe 'deb blah # blah' /etc/apt/sources.list

Edit:

A more complete version which allows you to pipe input in or redirect from a file and includes a -a switch to turn off appending (which is on by default):

sudoe() {
  if ([[ "$1" == "-a" ]] || [[ "$1" == "--no-append" ]]); then
    shift &>/dev/null || local failed=1
  else
    local append="--append"
  fi

  while [[ $failed -ne 1 ]]; do
    if [[ -t 0 ]]; then
      text="$1"; shift &>/dev/null || break
    else
      text="$(cat <&0)"
    fi

    [[ -z "$1" ]] && break
    echo "$text" | sudo tee $append "$1" >/dev/null; return $?
  done

  echo "Usage: $0 [-a|--no-append] [text] <file>"; return 1
}

Solution 10 - Bash

By using **sed -i *** with *$ a , you can append text, containing both variables and special characters, after the last line.

For example, adding $NEW_HOST with $NEW_IP to /etc/hosts:

sudo sed -i "\$ a $NEW_IP\t\t$NEW_HOST.domain.local\t$NEW_HOST" /etc/hosts

sed options explained:

-i for in-place
$ for last line
a for append

Solution 11 - Bash

You can also use sponge from the moreutils package and not need to redirect the output (i.e., no tee noise to hide):

echo 'Add this line' | sudo sponge -a privfile

Solution 12 - Bash

echo 'Hello World' | (sudo tee -a /etc/apt/sources.list)

Solution 13 - Bash

How about:
echo text | sudo dd status=none of=privilegedfile
I want to change /proc/sys/net/ipv4/tcp_rmem.
I did:
sudo dd status=none of=/proc/sys/net/ipv4/tcp_rmem <<<"4096 131072 1024000"
eliminates the echo with a single line document

Solution 14 - Bash

This worked for me: original command

echo "export CATALINA_HOME="/opt/tomcat9"" >> /etc/environment

Working command

echo "export CATALINA_HOME="/opt/tomcat9"" |sudo tee /etc/environment

Solution 15 - Bash

Can you change the ownership of the file then change it back after using cat >> to append?

sudo chown youruser /etc/hosts  
sudo cat /downloaded/hostsadditions >> /etc/hosts  
sudo chown root /etc/hosts

Something like this work for you?

Content Type	Original Author	Original Content on Stackoverflow
Question	David	View Question on Stackoverflow
Solution 1 - Bash	Yoo	View Answer on Stackoverflow
Solution 2 - Bash	Matt P	View Answer on Stackoverflow
Solution 3 - Bash	Incident	View Answer on Stackoverflow
Solution 4 - Bash	Vinko Vrsalovic	View Answer on Stackoverflow
Solution 5 - Bash	agnul	View Answer on Stackoverflow
Solution 6 - Bash	msanford	View Answer on Stackoverflow
Solution 7 - Bash	Vytenis Bivainis	View Answer on Stackoverflow
Solution 8 - Bash	abkrim	View Answer on Stackoverflow
Solution 9 - Bash	hololeap	View Answer on Stackoverflow
Solution 10 - Bash	Noam Manos	View Answer on Stackoverflow
Solution 11 - Bash	Michael Goldshteyn	View Answer on Stackoverflow
Solution 12 - Bash	Sudev Shetty	View Answer on Stackoverflow
Solution 13 - Bash	Marcelo Pacheco	View Answer on Stackoverflow
Solution 14 - Bash	Fthi.a.Abadi	View Answer on Stackoverflow
Solution 15 - Bash	pixistix	View Answer on Stackoverflow