[FAQ] "Command not found" when using su

[Head_on_a_Stick]

The su command in Debian buster is now provided by the util-linux package rather than the login package and it will not include the /sbin directories in PATH unless it is called like this:

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su -

^ Note the dash after the command.

Alternatively, to get an approximation of the old behaviour add this line to /etc/login.defs:

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ALWAYS_SET_PATH yes

See also https://www.debian.org/releases/buster/ ... -variables & https://bugs.debian.org/cgi-bin/bugrepo ... bug=905409

[cuckooflew]

Thanks again, much needed this Howto, I lost count on how many posts there are, and it was because the person between the chair and keyboard did not know about the new way su is handled on Debian. It had me confused when I first installed Debian 10, but I did some searches, and read about it here: https://wiki.debian.org/NewInBuster

[mrkapqa]

: https://wiki.debian.org/NewInBuster

This info suggests using "sudo" instead of "su" .
but to get sudo working, i always had to to do "usermod -aG sudo username" as root
and to get to root it seems that "su" is no more appropriate.

i do understand that when one upgrades from an earlier edition , this info might be included and shown during the upgrade , but for new installs this info is nowhere to be seen.
I think it would be fair that an info screen would display such a " major change" after or during installation.

so in either case it is a bit confusing, and it doesn't clearly state why this change was necessary, if at all.

[Bulkley]

The su command in Debian buster is now provided by the util-linux package rather than the login package . . .

Not to sideline your information but do you have any idea why they did that? I've been using su for 20+ years without issue and now, seemingly out of the blue, someone decided to change it. Geez, when something works, don't fix it.

[Head_on_a_Stick]

to get sudo working, i always had to to do "usermod -aG sudo username" as root

If no root password is entered in the installer then the sudo package is installed and the first user is added to the sudo group automatically. Please continue any further discussion in your other thread, it is off-topic here, thanks.

do you have any idea why they did that?

To align Debian with the other major distributions, this bug report has the full discussion: https://bugs.debian.org/cgi-bin/bugrepo ... bug=905409

[sickpig]

pkexec is in built, why not use that?

[Head_on_a_Stick]

pkexec is in built

Not necessarily:

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E485:~$ pkexec apt update
loksh: pkexec: not found
E485:~127$

And pkexec will not include the /sbin directories in PATH so the command will still not be found.

[Ardouos]

Another solution could be to alias "su -" in your .bashrc or globally in /etc/bashrc and /etc/bash.bashrc.

e.g.

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alias su="su -"

[sunrat]

Another solution could be to alias "su -" in your .bashrc or globally in /etc/bashrc and /etc/bash.bashrc.

That means you would not be able to use su in cases where you don't want to change the environment. I occasionally install a downloaded .deb and I can just use su in ~/Downloads/ to install it with apt as /usr/bin is in my user's environment but /sbin and /usr/sbin are not. apt is in /usr/bin.
I've seen some other chat why aliasing su is not advisable but can't recall right now.

[dilberts_left_nut]

It would also break su'ing to other users.

[sunrat]

It would also break su'ing to other users.

I was going to write that but thought maybe it would just change to the other user's environment?

[dilberts_left_nut]

Yeah, you're right according to the man page.
I thought the contraction of -l to just - was only valid for root (by omitting <user>), but seems not.

[Ardouos]

Oh, I understand, forgive my ignorance. Best to leave it there so that others know I guess?