/ # ls -lh /bin/busybox
-rwxr-xr-x    1 root     root      797.7K May  5 06:41 /bin/busybox
/ # adduser student
Changing password for student
New password:
Bad password: too short
Retype password:
passwd: password for student changed by root
/ # su student -
/ $
/ # echo 'student ALL=(ALL)       ALL'   >> /etc/sudoers
/ # visudo -c
/bin/sh: visudo: not found
/ # apk add visudo
fetch https://dl-cdn.alpinelinux.org/alpine/v3.18/main/x86_64/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/v3.18/community/x86_64/APKINDEX.tar.gz
ERROR: unable to select packages:
  visudo (no such package):
    required by: world[visudo]
/ # apk add sudo
(1/1) Installing sudo (1.9.13_p3-r2)
Executing busybox-1.36.0-r9.trigger
OK: 9 MiB in 16 packages
/ # visudo -c
/etc/sudoers: bad permissions, should be mode 0440
/ # chmod 0440 /etc/visudo
chmod: /etc/visudo: No such file or directory
/ # chmod 0440 /etc/sudoers
/ # visudo -c
/etc/sudoers: parsed OK
/ # su student -
/ $ sudo su -
We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:

    #1) Respect the privacy of others.
    #2) Think before you type.
    #3) With great power comes great responsibility.

For security reasons, the password you type will not be visible.

[sudo] password for student:
efb779e4dab8:~#