Take the 2-minute tour ×
Ask Different is a question and answer site for power users of Apple hardware and software. It's 100% free, no registration required.

Apologies in advance if this question is going to annoy the hell out of everyone as I appreciate, it's been asked in various ways many times before. Please be assured, I have read the archives and have tried at least some of the suggestions but still cannot resolve the (simple) issue. Hopefully someone can provide an answer and I can feel appropriately humbled. FYI, for the avoidance of any ambiguity, I'm going to use absolute rather than relative paths.

When I log in, I do so as user adam. The aliases in /Users/adam/.bash_profile are loaded and I can use them immediately upon pulling up a terminal. I don't use a .bashrc file and that's fine.

Every now and then, I switch to root by typing su into the terminal and then entering my password. The prompt changes and I am now root user. My question is this: immediately upon becoming root, can my root bash profile be loaded without me having to manually source the profile file? The reason I know it doesn't happen automatically is because I have the same aliases in my root profile file and my /Users/adam/.bash_profile. After becoming root user, unless I type in source [root_profile_file], they don't work. I have tried setting up the following permutations and then switching to root via the terminal but none of them automatically source the profile/aliases (note, I don't have any of the options below set up concurrently so I don't think I'm confusing the system):

Option 1: put my aliases in /etc/profile

Option 2:

  • in /etc/profile, insert [ -r /etc/bashrc ] && . /etc/bashrc
  • put my aliases in /etc/bashrc

Option 3:

  • in /etc/bash_profile, insert [ -r /etc/bashrc ] && . /etc/bashrc
  • put my aliases in /etc/bashrc

Option 4: put my aliases in /var/root/.profile

Option 5:

  • in /var/root/.profile, insert [ -r /var/root/.bashrc ] && . /var/root/.bashrc
  • put my aliases in /var/root/.bashrc

Option 6:

  • in /var/root/.bash_profile, insert [ -r /var/root/.bashrc ] && . /var/root/.bashrc
  • put my aliases in /var/root/.bashrc

Please note, with any of the above, if I switch to root and then type source root_profile_file the aliases are loaded but only if I do indeed source the file manually. Perhaps I've totally misunderstood how bash works and it's not possible to source a profile file automatically after switching to root but I'm hoping there is a simple solution. Thanks in advance to anyone who's taken the time to read this message.

share|improve this question

6 Answers 6

The problem you are encountering is that when you run su by itself, you are not entering a 'login' shell. This means that your environment, working directory, and everything except uid/gid remain the same of the original user.

Login triggers do not execute, and you experience the issues you describe.

A simple solution to a simple problem:

su -

From the su(1) man page:

The su command is used to become another user during a login session. Invoked without a username, su defaults to becoming the superuser. The optional argument - may be used to provide an environment similar to what the user would expect had the user logged in directly.

Also:

   -, -l, --login
       Provide an environment similar to what the user would expect had the user logged in directly.

If you su into a login shell, bash will behave as you expect, and automatically source the appropriate files on "login", without the need for overly hacky workarounds.

share|improve this answer
1  
I will however second Hai Vu's notes: You really, really, really should never su nor work as root. There is sudo for that purpose, or you can work in such a way that you don't require root privileges at all. –  Jason Salaz Mar 14 '12 at 18:33
    
Thank you to both you and @Hai Vu. "su -" does the trick and yes, completely understood, root should generally be avoided. –  Adam Gold Mar 14 '12 at 19:39
    
I already knew to add the '-' after the su command, but still was not getting my .bash_profile for the root user sourced. Florian Bidabe's and patrix's answer below about changing the root shell from sh to bash fixed the problem for me. –  JaredC Sep 25 at 11:19

When I absolutely must, I sudo bash which makes me root but with JRobert's environment. My .bashrc contains:

# Prompt: 'jrobert@JRiMac ~' in green (red, if I'm root), '$' in white
if [[ $UID == 0 ]]; then
   export PS1="\[\e[1;31;40m\]\u@\h \W\[\e[0m\]\$ "
else
   export PS1="\[\e[32;40m\]\u@\h \W\[\e[0m\]\$ "
fi

, to make the root-prompt glare back at me in RED to emphasize that I'm now (more) vulnerable to my own [pick one: brashness, dumbness, fat-finger tendencies, unwillingness to take good advice, up s.creek - don't drop the paddle].

share|improve this answer

Actually root uses /bin/sh (old bourne shell), .bash_profile and .bashrc are read by bash.

It becomes tricky as those files may use functionality not available in sh. Even if you source .bashrc or source .bash_profile, you will still have some issue with complex functions for instance.

One way to solve this is to run

sudo dscl . -change /Users/root UserShell /bin/sh /bin/bash

to switch root's shell to bash.

share|improve this answer

In general, I advice against su as it is dangerous, just search for it and you know why. On to your question, the root account works the same way your account does: it source ~/.bash_profile and/or ~/.bashrc. I don't know which one, but my intuition leans toward ~/.bashrc, so you might want to try to put your aliases there. Here is a suggestion:

su           # type password to get into root account
vi ~/.bashrc # put your aliases there
exit         # exit your root session
su           # try again to see if your aliases works
share|improve this answer

I am using sudo -i to switch to to root user. In this case, shell configuration is read from /var/root/.profile.

share|improve this answer

if you have only one 'default' user and the root user you can put alias su="su -" on .bash_profile of the 'default' user and you get the effect you want. Works and with no hacky things.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.