Wednesday, October 24, 2012

sudo -s on RHEL 6 doesn't preserve HOME


If you're the only one using this machine, the easiest fix is to run this command as root:

and then add this line to the sudoers file:
Defaults env_keep=HOME

If this is a shared computer and you aren't at liberty to change the sudoers file, you can add this code to .bashrc in your home directory. be sure to log out and back in for it to take effect:

# hack to preserve home when using sudo -s on rhel 6
if [[ `cat /etc/*release | grep "release 6"` ]]; then
    sudo() {
        if [[ $@ == "-s" ]]; then
            sudo bash -c "HOME=$HOME; exec bash"
            command sudo "$@";


In linux, if I want to become root but keep my user's environment (home, aliases, etc), I normally use sudo -s:
[user@computer ~]$ sudo -s
[root@computer ~]# echo $HOME

and if I want to become root and use root's environment, I'll use sudo -i:
[user@computer ~]$ sudo -i
[root@computer ~]# echo $HOME

The above works on Ubuntu, and all versions of RHEL up to 5 (the same probably goes for CentOS). however, I recently noticed that RHEL 6 , my home variable isn't preserved when using sudo -s:
[user@computer ~]$ sudo -s
[root@computer user]# echo $HOME

The most frustrating thing is that because of this, it seems like my .bashrc wasn't being called, and so I didn't have access to my aliases any more.

It seems like the cause of this is that the default in RHEL 6 is not to preserve the home variable. you can see this running this command as root:
sudo -V

If you look under the list of "Environment variables to preserve," you'll notice that in RHEL 5 HOME is listed, but in RHEL 6 it isn't.

Wednesday, October 10, 2012

uninstalling problematic rpms

if you're unable to uninstall an rpm using yum erase/remove or rpm -e because something in the rpm's uninstallation process is broken, try using rpm -e with the --noscripts --notriggers flags:

$ sudo rpm -e sblim-sfcb
/var/tmp/rpm-tmp.54035: line 7: /etc/init.d/sfcb: No such file or directory
error: %preun(sblim-sfcb-1.3.11-0.7.14.x86_64) scriptlet failed, exit status 127
$ sudo yum remove sblim-sfcb
Running Transaction
/var/tmp/rpm-tmp.49575: line 7: /etc/init.d/sfcb: No such file or directory

sblim-sfcb.x86_64 0:1.3.11-0.7.14

$ rpm -qa sblim-sfcb
$ sudo rpm -e sblim-sfcb --noscripts --notriggers
$ rpm -qa sblim-sfcb