Why does sudo change the PATH

environment-variablespathsudo

This is the PATH variable without sudo:

$ echo 'echo $PATH' | sh 
/opt/local/ruby/bin:/usr/bin:/bin

This is the PATH variable with sudo:

$ echo 'echo $PATH' | sudo sh
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/X11R6/bin

As far as I can tell, sudo is supposed to leave PATH untouched. What's going on? How do I change this? (This is on Ubuntu 8.04).

UPDATE: as far as I can see, none of the scripts started as root change PATH in any way.

From man sudo:

To prevent command spoofing, sudo
checks “.'' and “'' (both denoting
current directory) last when searching
for a command in the user's PATH (if
one or both are in the PATH). Note,
however, that the actual PATH
environment variable is not modified
and is passed unchanged to the program
that sudo executes.

Best Solution

This is an annoying function a feature of sudo on many distributions.

To work around this "problem" on ubuntu I do the following in my ~/.bashrc

alias sudo='sudo env PATH=$PATH'

Note the above will work for commands that don't reset the $PATH themselves. However `su' resets it's $PATH so you must use -p to tell it not to. I.E.:

sudo su -p