jvian10 at charter.net
Wed Sep 8 22:12:55 UTC 2004
On Wed, 2004-09-08 at 14:13, Robert Locke wrote:
> On Wed, 2004-09-08 at 13:58, Nifty Hat Mitch wrote:
> > On Wed, Sep 08, 2004 at 08:02:27AM +0200, Joachim Backes wrote:
> > > can somebody tell me where the PATH variable is initially set? I'm
> > > sure, not in /etc/profile.
> > The strict answer to this is that it is set
> > by init (/sbin/init).
> > PATH=/usr/local/sbin:/sbin:/bin:/usr/sbin:/usr/bin
> > Since init is the first process from which all other processes are
> > created this is the answer to your question.
> > Once init is running the topic expands through /etc/inittab processing
> > which includes all the scripts in /etc/init.d.
> > One of these steps is especially interesting for users at run level 5.
> > # Run xdm in runlevel 5
> > x:5:respawn:/etc/X11/prefdm -nodaemon
> > The first line with code in it resets the path thus:
> > PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/X11R6/bin
> > Now that a display manager is running it might be reset again.
> > For gdm we see this line in /usr/bin/gdm.
> > test -f /etc/profile && . /etc/profile
> > /etc/profile does its pathmunge thing....
> > and then all these are /etc/profile.d/*.sh so if
> > kerberos is there krb5.sh will modify it again.
> > All of this might be interesting because a process launched with a
> > quick click from the desktop by the window manager might act
> > differently when compared to the same process launched from a shell
> > prompt.
> > Not to be left out is your shell as defined in /etc/passwd
> > (bash, csh, tcsh, ksh, sh, zsh). Each shell has rules for
> > startup and standard files it looks at... often PATH is reset
> > there. The csh and tcsh world is funny because $path is
> > almost equal to $PATH (RTFM).
> > --
> > T o m M i t c h e l l
> > Just say no to 74LS73 in 2004
> I need to contest some of what you are saying.... For one, where do
> several of the directories you quote get removed from the $PATH of a
> regular user, if I am using the "init" process' $PATH?
> So let me quote man bash:
> > PATH The search path for commands. It is a colon-separated list of
> > directories in which the shell looks for commands (see COMMAND
> > EXECUTION below). The default path is system-dependent, and is
> > set by the administrator who installs bash. A common value is
> > ‘‘/usr/gnu/bin:/usr/local/bin:/usr/ucb:/bin:/usr/bin:.’’.
> In doing a strings of /bin/bash, I notice a string of
> Using that as a basis, then reading /etc/profile makes sense, when it
> adds /sbin, /usr/sbin, and /usr/local/sbin if I am root. It also adds
> /usr/X11R6/bin to the end for anybody.... This seems to match what I
> see when I launch either a gnome-terminal or log in via a virtual
> I have to admit the thought of this being hard-coded into /bin/bash
> bothers me, but....
> Any thoughts?
Why would that minimal path bother you?
It is designed so that EVERY user has that minimal path, and in practice
the processing of a file such as $HOME/.bash_profile adds the user
specific additional pathing, and /etc/profile adds /sbin etc for root.
This was specifically defined to allow all users access to common
user-space commands and to limit system management commands to the
Files used vary depending on the shell being invoked, but every shell
has a similar method for customizing a users path to their needs..
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