what is an environment variable?

Robert P. J. Day rpjday at crashcourse.ca
Sat Mar 17 00:21:20 UTC 2012

On Fri, 16 Mar 2012, Smoot Carl-Mitchell wrote:

> On Fri, 2012-03-16 at 23:03 +0000, Thufir Hawat wrote:
> > I've looked at
> > https://help.ubuntu.com/community/EnvironmentVariables and some
> > other resources, but it's still unclear to me *what* $PATH is.
> > There's no corresponding file, just various files which add to the
> > this variable.  (It's a shell variable?)
> PATH is an exported shell variable.  So it shows up as part of the
> environment in a forked process.

  just my $0.02, but i like to avoid PATH being part of the
*environment*.  it's obviously a useful *shell* variable but, if you
think about it, its value is to locate commands based on how
complicated you want to make your search path.

  *however*, once the command is located, it's generally safer if
*those* commands use a standard search path, and not your overly
complicated one.  that's why you see so many people who, at the top
of their shell scripts, have a line like:


it's specifically to avoid having a shell script having to deal with
an arbitrarily insane setting of PATH based on who invokes it.

  or is there some compelling reason to export PATH that i'm missing?



Robert P. J. Day                                 Ottawa, Ontario, CANADA

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