I've created new test user (sudo adduser test), added to sudo via sudo usermod test -G sudo.

Then I switch to other terminal (Alt-Ctrl-F2), login as test, sudo echo a: "a" - ok, but startx, start gnome terminal and sudo echo a output "user is not allowed to execute '/usr/bin/echo a' as root". Any ideas why? TIA

This "feature" appears to work only with liveISO boot, I wonder how it works, live boot is still Linux, the only difference I know with regular one is in using overlayfs for root / to put modifiable fs on top of non-modifiable file with all / from iso.

/etc/sudoers just list %sudo ALL ALL, sudo -l does not show anything for test. (those possible causes of error I've found vie web search and checked out).

System: Linux Mint 21, liveiso boot.

1 Answer 1


This might sound silly but have you tried logging in again, logout > login. For a new group membership to be effective this is required under linux.

  • Full story: you get your user and groups at login (and in part of login procedure). They are not checked dynamically. You can also ssh locally, if you cannot logout. (or with su, etc, but possibly you do not have access to it now) Dec 15, 2022 at 9:39
  • Thanks, I have not said it explicitly. I typed startx right after confirming sudo works. so yes, it all was after re-login (or on first login of new account). I've noted it is for liveISO boot and edited the question. Yet another thing I notice about liveISO/USB boot. I'm curious how it is done to work like that. Dec 16, 2022 at 2:58

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