sudo and regular user execution

[BlackVeils]

i created system setup scripts, to configure things and install software, everything is exactly how i want it.

from what i had read, you can execute a script with sudo, and it wont time-out. then to run commands with regular user privileges, you can use sudo -u username. but i just did a test of that for opening a secondary script as user, and it asked for sudo password in the secondary script window, when there was no reason for it to.

am i missing something? is this even achievable? i'm sure i tested this concept, as i test everything, but its the launching of a secondary that isnt working as expected. here is the command:

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sudo -u vicky nohup x-terminal-emulator -e '/home/vicky/Downloads/OS Setup/OS-Setup-flash-extract.sh' 2>&1 | tee command-output.txt &
sleep 5

now i'm wondering if all the other user commands are actually being executed with sudo privileges.

[niowluka]

you can execute a script with sudo, and it wont time-out

That's not strictly true. It will time out after 10 minutes, by default.

Also, it only applies to current session. If you run second command in another session, you must authenticate again.

[BlackVeils]

That's not strictly true. It will time out after 10 minutes, by default.

i've tested the sudo script time-out thing, as long as it was directly loaded with sudo, it works.

anyway, i must have had tired blindspot lastnight, there was a sudo in my secondary test script! but this gets wierder..

i did some tests just now, and the secondary script loads just fine, and executes commands as user, not root. but the commands in the initial sudo script are running as root, when i ran them with sudo -u vicky, the same way i run the secondary script!

i'm confused

>> Edited:

more testing shows that various commands work as intended in the sudo script, either as root or vicky, except for echo if you want to create/edit a file. you need to use touch to create the file if it does not already exist, then edit with echo, otherwise it gets changed to root permissions even when using sudo -u vicky.

i suppose this is solved, but i will be wary of which commands will not obey sudo -u username.

[niowluka]

more testing shows that various commands work as intended in the sudo script, either as root or vicky, except for echo if you want to create/edit a file. you need to use touch to create the file if it does not already exist, then edit with echo, otherwise it gets changed to root permissions even when using sudo -u vicky.

i suppose this is solved, but i will be wary of which commands will not obey sudo -u username.

All commands 'obey' sudo. I guess you are refering to echo redirect

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sudo echo text > file

echo is executed with sudo privileges, but the part after redirect is not affected. You need to wrap the whole command in another one, e.g.

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sudo sh -c "echo text > file"

'sh' is executed with sudo and parses the entire command with acquired privileges.

[hupnuk]

i suppose this is solved, but i will be wary of which commands will not obey sudo -u username.

All commands 'obey' sudo. I guess you are refering to echo redirect

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sudo echo text > file

echo is executed with sudo privileges, but the part after redirect is not affected. You need to wrap the whole command in another one, e.g.

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sudo sh -c "echo text > file"

'sh' is executed with sudo and parses the entire command with acquired privileges.

The problem though with using 'sh -c' though is more complex commands may not work or need to be escaped/fixed.
Instead i would pipe the output of echo to 'tee'.

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echo 'testcommand' | sudo tee 'file' 1> /dev/null 

If you want to run commands in both sudo and regular user without having to fear the timeout period, i have written a script specially for this task.

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#!/bin/sh
if [ "$(id -u)" -ne 0 ]; then
   if [ "$1" != '--nosudo' ]; then
      printf '%s\n' 'Please run this script with sudo'
      sudo "$0"
      exit 0
   else
      #### Everything here will run in only normal user
      echo "$USER"
      echo 'b'
   fi
elif [ -z "$SUDO_USER" ]; then
   printf '%s\n' 'This script should be run from a sudo user, not pure root.'
   exit 1
else
   #### Everything here will run in only sudo user
   echo "$USER"
   echo 'a'
   #### This command will run this script in normal user using parameter --nosudo, it also uses the '$HOME' of normal user
   sudo -Hu "$SUDO_USER" sh -c "$0 --nosudo"
fi
   #### Everything here will run in both sudo and normal user
   echo "$USER"
   echo 'c'
exit 0

If you execute this script with parameter '--nosudo', it will not run with sudo.
It will check if your running as pure root or sudo user though.

Hope it helps.