Bash: Sudo keep-alive (good for long-running scripts that need sudo internally but shouldn't be run with sudo)

sudo-keepalive-example.sh

#!/bin/bash

# Might as well ask for password up-front, right?
sudo -v

# Keep-alive: update existing sudo time stamp if set, otherwise do nothing.
while true; do sudo -n true; sleep 60; kill -0 "$$" || exit; done 2>/dev/null &

# Example: do stuff over the next 30+ mins that requires sudo here or there.
function wait() {
  echo -n "["; for i in {1..60}; do sleep $1; echo -n =; done; echo "]"
}
wait 0 # show reference bar
echo "$(sudo whoami) | $(date)"
wait 1
echo "$(sudo whoami) | $(date)"
wait 2
echo "$(sudo whoami) | $(date)"
wait 5
echo "$(sudo whoami) | $(date)"
wait 10
echo "$(sudo whoami) | $(date)"
wait 15
echo "$(sudo whoami) | $(date)"
wait 1
sudo -K
echo "$(whoami) | $(date)"
wait 2
echo "$(whoami) | $(date)"
wait 5
echo "done."

I was thinking about something like this but it doesn't handle the case where sudo expires immediately

@spudowiar, I recently changed my dotfiles to use the sledge-hammer approach to sudoing by adding myself to /etc/sudoers for the duration of the script, because anything else just wouldn't work reliably.

https://github.com/reitermarkus/dotfiles/blob/f104a8a7a592204a66646810ae8fbd956023c988/.sh#L43-L60

Maybe that will work for your case.

Awesome... That's exactly what I'm looking for. Unfortunately it does not work with a long running task like a massive brew install. After that, the sudo session is expired and you have to re-enter a password for the next sudo command. @cowboy Do you have any hints/experiences on that?!

I think the following statement:

while true; do sudo -n true; sleep 60; kill -0 "$$" || exit; done 2>/dev/null &

Should be changed to:

while true; do sleep 60; sudo -n true; kill -0 "$$" || exit; done 2>/dev/null &

Because an immediate call to sudo right after the first one is not only redundant, but would also cause sudo to ask password again for the second real sudo call (at lease in my testing case).

Awesome... That's exactly what I'm looking for. Unfortunately it does not work with a long running task like a massive brew install. After that, the sudo session is expired and you have to re-enter a password for the next sudo command. @cowboy Do you have any hints/experiences on that?!

Homebrew explicitly invalidates the sudo timestamp, so AFAIK there's no way for this to work with brew.

@cowboy are you saying that this attempt at a solution didn't work? https://gist.github.com/cowboy/6733297

Has anyone tried this solution with the following sequence of commands:

sudo apt-get -y update
sudo apt-get -y upgrade
sudo apt-get -y autoremove

local packages=(tree curl unzip htop gconf-service gconf-service-backend gconf2
            gconf2-common libappindicator1 libgconf-2-4 libindicator7
            libpython2-stdlib python python2.7 python2.7-minimal libatomic1
            gimp vlc)

sudo apt-get -y install ${packages[@]}

sudo apt-get -y update

# At this point it asks me again the password
sudo apt-get -y install gufw

For me it didn't work.

Does sudo count the times is called along with the timeout? Because I see I'm using a few redundant apt-get update.

FYI: I'm running ubuntu 20.04