[SOLVED] why is /usr/sbin not in root's path?

cmk77 · 04-18-2024, 04:29 AM

I've been using debian bullseye for a while now and noticed that /usr/sbin is not by default in root's path, contrary to other distros. This leads some (third-party) scripts to fail, for instance because they cannot find ldconfig. What, if any, would be the reason debian ommits /usr/sbin from root's path?

Code:

$ whoami
root
$ echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
$

murugesandins · 04-18-2024, 04:59 AM

I used to use the following at windows (CYGWIN bash.exe)
~/.bashrc file:

Code:

$ /usr/bin/gawk.exe '{ if( ( 8 <= NR ) && ( 11 >= NR ) )  { print $0 } }'  ~/.bash_profile
if [[ -f ~/.bashrc ]]]
then
        . ~/.bashrc
fi

Few contents inside ~/.bashrc file:

Code:

if [[ -d /usr/sbin ]]
then
        echo "$PATH" | /usr/bin/grep -E "^/usr/sbin:|:/usr/sbin:|:/usr/sbin$" 2>&1 |\
        /usr/bin/grep -E -v "^$" >/dev/null 2>&1
        Ret=$?
        if [[ 0 -ne $Ret ]]
        then
                export PATH="/usr/sbin:$PATH"
        fi
fi
if [[ -d /usr/bin ]]
then
        echo "$PATH" | /usr/bin/grep -E "^/usr/bin:|:/usr/bin:|:/usr/bin$" 2>&1 |\
        /usr/bin/grep -E -v "^$" >/dev/null 2>&1
        Ret=$?
        if [[ 0 -ne $Ret ]]
        then
                export PATH="/usr/bin:$PATH"
        fi
fi
if [[ -d /bin ]]
then
        echo "$PATH" | /usr/bin/grep -E "^/bin:|:/bin:|:/bin$" 2>&1 |\
        /usr/bin/grep -E -v "^$" >/dev/null 2>&1
        Ret=$?
        if [[ 0 -ne $Ret ]]
        then
                export PATH="/bin:$PATH"
        fi
fi
if [[ -d /sbin ]]
then
        echo "$PATH" | /usr/bin/grep -E "^/sbin:|:/sbin:|:/sbin$" 2>&1 |\
        /usr/bin/grep -E -v "^$" >/dev/null 2>&1
        Ret=$?
        if [[ 0 -ne $Ret ]]
        then
                export PATH="/sbin:$PATH"
        fi
fi

I agree that we can similar kind of changes inside /etc/bash.bashrc using root(Windows Admin) user.

michaelk · 04-18-2024, 05:14 AM

I am guessing you are using su to login as root. su still uses the user's path environment but su - switches to root's environment. debian does not add /usr/sbin to the user's path while others do.

Turbocapitalist · 04-18-2024, 06:47 AM

Yes, if you are switching to root using su then you will need the -l option to start with an environment similar to a real root login.

cmk77 · 04-18-2024, 09:16 AM

Indeed, I was using su without flags, thanks for clarifying.
- debian does have /usr/sbin in root's path (but not in a user's path)
- su without -l preserves that user's environment

_blackhole_ · 04-18-2024, 11:10 AM

Quote:

Originally Posted by cmk77

What, if any, would be the reason debian ommits /usr/sbin from root's path?

Absolutely no idea, but it's just annoying. There are certain commands in /sbin you may want to run as a normal user (such as ifconfig).

In Debian, my method is to set the $PATH variable early in ~/.profile as follows:

Code:

# ~/.profile: executed by the command interpreter for login shells.
# This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login
# exists.
# see /usr/share/doc/bash/examples/startup-files for examples.
# the files are located in the bash-doc package.

# the default umask is set in /etc/profile; for setting the umask
# for ssh logins, install and configure the libpam-umask package.
#umask 022
export PATH=$PATH:/usr/local/sbin:/usr/sbin:/sbin
[...]

Log out and back in.

Even when the path is set as above, you should still su to root as follows in order to use root's environment:

Code:

$ su -l

friendlysalmon8827 · Yesterday, 07:30 PM

The reason that certain utilities and system programs aren't directly in the root or super users' path is because the /sbin folder is a symbolic link back to the user sbin folder.

murugesandins · Yesterday, 07:50 PM

Quote:

Originally Posted by cmk77

Indeed, I was using su without flags, thanks for clarifying.
- debian does have /usr/sbin in root's path (but not in a user's path)
- su without -l preserves that user's environment

if I am facing this issue:
I should have added following code inside ~/.bashrc or ~/.kshrc or ~/.mkshrc based on different OS
for all users including root user

Code:

OS=$(/usr/bin/uname -s 2>&1 | /usr/bin/sed "s/-[0-9]*\.[0-9]*\-[0-9]*//;")
case $OS in
        "Linux")
                if [[ -f /usr/bin/grep ]]
                then
                        EGREP="/usr/bin/grep -E"
                elif [[ -f /usr/bin/egrep ]]
                then
                        EGREP="/usr/bin/egrep"
                fi
                ;;
        "SunOS")
                if [[ -f /usr/bin/grep ]]
                then
                        EGREP="/usr/bin/grep -E"
                elif [[ -f /usr/bin/egrep ]]
                then
                        EGREP="/usr/bin/egrep"
                fi
                ;;
        "AIX")
                if [[ -f /usr/bin/grep ]]
                then
                        EGREP="/usr/bin/grep -E"
                elif [[ -f /usr/bin/egrep ]]
                then
                        EGREP="/usr/bin/egrep"
                fi
                ;;
        "HP-UX")
                if [[ -f /usr/bin/grep ]]
                then
                        EGREP="/usr/bin/grep -E"
                elif [[ -f /usr/bin/egrep ]]
                then
                        EGREP="/usr/bin/egrep"
                fi
                ;;
        "CYGWIN_NT")
                if [[ -f /usr/bin/grep ]]
                then
                        EGREP="/usr/bin/grep -E"
                elif [[ -f /usr/bin/egrep ]]
                then
                        EGREP="/usr/bin/egrep"
                fi
                ;;
        *)
                #echo use related path to grep
                if [[ -f /usr/bin/grep ]]
                then
                        EGREP="/usr/bin/grep -E"
                elif [[ -f /usr/bin/egrep ]]
                then
                        EGREP="/usr/bin/egrep"
                fi
                ;;
esac
if [[ -d /usr/sbin ]]
then
        echo $PATH 2>&1 |\
        $EGREP "^/usr/sbin:|:/usr/sbin:|:/usr/sbin$" >/dev/null 2>&1
        Ret=$?
        if [[ 0 -ne $Ret ]]
        then
                export PATH="/usr/sbin:$PATH"
        else #DEBUG01
                echo "\$PATH having /usr/sbin" #DEBUG02
        fi
else #DEBUG03
        /usr/bin/ls -ltrd /usr/sbin #DEBUG04
fi