sudo echo “something” >> /etc/privilegedFile doesn't work
-
01-07-2019 - |
Question
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?
Solution
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
OTHER TIPS
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"
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"
sudo sh -c "echo 127.0.0.1 localhost >> /etc/hosts"
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.
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"
In bash you can use tee
in combination with > /dev/null
to keep stdout clean.
echo "# comment" | sudo tee -a /etc/hosts > /dev/null
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
}
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
echo 'Hello World' | (sudo tee -a /etc/apt/sources.list)
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
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
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?