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I have a relatively fresh RHEL 6.5 install, on to which I have installed from source GCCC 4.9. After I installed GCC 4.9, I uninstalled the distro-provided older GCC version via:

sudo yum remove gcc

GCC appears to be correctly installed and visible to both users and root, but when I try to issue a sudo command which needs the compiler, it cannot be found.

It seems to me that PATH doesn't point to g++ during sudo, but I don't understand why.

g++ is installed in:

[john@haley boost_1_55_0]$ which g++
/usr/local/bin/g++

And getting the version as a user and as root succeeds:

[john@haley boost_1_55_0]$ g++ --version
g++ (GCC) 4.9.0
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[john@haley boost_1_55_0]$ sudo su -
root@haley /root # g++ --version
g++ (GCC) 4.9.0
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

But sudo g++ --version fails:

john@haley boost_1_55_0]$ sudo g++ --version
[sudo] password for john: 
sudo: g++: command not found
[john@haley boost_1_55_0]$

Checking the PATH as sudo:

[john@haley boost_1_55_0]$ sudo echo $PATH
/usr/lib64/qt-3.3/bin:/usr/local/:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/home/john/bin:/usr/local/bin
                                                                             ^^^^^^^^^

... seems to indicate that the location of g++ is actually in the path.

Why is this failing, and what can I do to fix it?

Answering questions in comments:

yes, I can execute it using explicit paths under sudo:

[john@haley boost_1_55_0]$ sudo /usr/local/bin/g++ --version
[sudo] password for john: 
g++ (GCC) 4.9.0
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[john@haley boost_1_55_0]$

It was observed that I was doing-it-wrong when checking the sudo PATH. Doing it the right way reveals that in fact /usr/local/bin is not in sudo's PATH:

[john@haley boost_1_55_0]$ sudo env | grep PATH
13:PATH=/sbin:/bin:/usr/sbin:/usr/bin
[john@haley boost_1_55_0]$
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  • Can you execute it if you use absolute pathnames with sudo? – psimon Jun 21 '14 at 14:57
  • @psimon: Yes; question edited with demo. – John Dibling Jun 21 '14 at 15:02
  • 2
    The way you're checking $PATH is wrong because $PATH expanded by the shell. Try sudo env | grep PATH. – Mikel Jun 21 '14 at 15:02
  • @Mikel: Quite right. Doing it the right way confirms that the directory is not in sudo's path. Question edited with demo. – John Dibling Jun 21 '14 at 15:04
  • Should I visudo and add /usr/local/bin to the secure_path? – John Dibling Jun 21 '14 at 15:07
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I'm posting this as an answer because I discovered this solution through comments on the OP, but I'm not sure that this is what I should do.

I can make this work by running sudo visudo and editing the secure_path to include /usr/local/bin.

On my system, the original line is:

Defaults    secure_path = /sbin:/bin:/usr/sbin:/usr/bin

Changing it to:

Defaults    secure_path = /sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin

"fixes" the problem:

[john@haley boost_1_55_0]$ sudo g++ --version
g++ (GCC) 4.9.0
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[john@haley boost_1_55_0]$
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