Why does `/sbin` not included in $PATH for new user?

Question

ifconfig is located in /sbin/ifconfig. I don't have problem issuing ifconfig command in root user.

The problem started when I created a new user.

root@Ubuntu:~# useradd -m user
root@Ubuntu:~#

root@Ubuntu:~# passwd user
Enter new UNIX password: 
Retype new UNIX password: 
passwd: password updated successfully
root@Ubuntu:~# 

root@Ubuntu:~# su user
user@Ubuntu:/root$ id
uid=1003(user) gid=1003(user) groups=1003(user)
user@Ubuntu:/root$ 

ifconfig is not found in the new user.

user@Ubuntu:~$ ifconfig
-su: ifconfig: command not found
user@Ubuntu:~$ 

Temporary workaround is execute it from full path /sbin/ifconfig

user@Ubuntu:~$ whereis ifconfig
ifconfig: /sbin/ifconfig /usr/share/man/man8/ifconfig.8.gz
user@Ubuntu:~$ 

user@Ubuntu:~$ /sbin/ifconfig
eth0      Link encap:Ethernet  HWaddr AA:AA:AA:AA:AA:AA
          inet addr:10.0.0.1  Bcast:10.0.0.255  Mask:255.255.255.0
user@Ubuntu:~$

ifconfig was not found as /sbin is no longer configured in the new user environment.

user@Ubuntu:~$ echo $PATH
/home/user/bin:/home/user/.local/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/snap/bin
user@Ubuntu:~$ 

user@Ubuntu:~$ echo $PATH | grep sbin
user@Ubuntu:~$ 

I don't see this issue on root user as /sbin is part of $PATH by default.

root@Ubuntu:~# ifconfig 
eth0      Link encap:Ethernet  HWaddr AA:AA:AA:AA:AA:AA
          inet addr:10.0.0.1  Bcast:10.0.0.255  Mask:255.255.255.0

root@Ubuntu:~# echo $PATH | grep sbin
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
root@Ubuntu:~# 

1. The question is why /sbin is not included by default? Doesn't this make things harder for user?

2. How to make sure /sbin is added automatically in $PATH instead of modifying it manually for each users?

Answer 1

The /sbin directory is for system maintenance and/or administrative tools. So only administrators are allowed to use it and you don't have this directory in your $PATH. You can read more in the Filesystem Hierarchy Standard FHS.

The right place to add new value to $PATH variable are user's ~/.profile file or system /etc/profile file. Usually there is already a line with $PATH so you need just to add /sbin to the start of the line. Or just add this line at the end of the file:

PATH="/sbin:$PATH"

Also you can edit /etc/skel/.profile file. This file will be copied to a user's home directory when you create a new one. But if you want to have this feature for all users, change /etc/profile.