Separator in $PATH

ruby-talk
1

Hello everyone,
  Unix-like operating systems use a colon to separate each directory in the PATH, while Windows uses a semicolon.

The question is: is there some class in the Ruby library that knows about this difference?
Or do I have to resort to something like the following?

  if RUBY_PLATFORM =~ /(win|w)32$/
    # ...
  end

I'm asking this question because I need to figure out if a given executable is in the path and, if it does, retrieve its full path.
So I whipped up this one-liner which seems to work as expected (except on Windows, of course):

ENV["PATH"].split(":").collect {|p| File.join(p, "foo")}.keep_if{|p| File.exist? p}.first

where "foo" is the name of the executable.
While we're at it, can someone think of a better / more idiomatic way to do it?

Obviously, simply trying to run the executable is not an option.

Thanks in advance.

···

--
Stefano

2

Hello everyone,
Unix-like operating systems use a colon to separate each directory in
the PATH, while Windows uses a semicolon.

The question is: is there some class in the Ruby library that knows
about this difference?

File::PATH_SEPARATOR

I'm asking this question because I need to figure out if a given
executable is in the path and, if it does, retrieve its full path.

require 'ptools'

File.which('ls') # => '/bin/ls'

Works on Windows, too, with or without an extension:

File.which('notepad') # Works
File.which('notepad.exe') # Also works

Regards,

Dan

···

On Oct 19, 2:02 pm, Stefano Mioli <stefano.mi...@gmail.com> wrote:

3

Many thanks, Dan.
I didn't know about ptools, and somehow I just saw File::SEPARATOR,
but not File::PATH_SEPARATOR.

···

On Tue, Oct 19, 2010 at 10:08 PM, Daniel Berger <djberg96@gmail.com> wrote:

On Oct 19, 2:02 pm, Stefano Mioli <stefano.mi...@gmail.com> wrote:

The question is: is there some class in the Ruby library that knows
about this difference?

File::PATH_SEPARATOR

I'm asking this question because I need to figure out if a given
executable is in the path and, if it does, retrieve its full path.

require 'ptools'

File.which('ls') # => '/bin/ls'

Works on Windows, too, with or without an extension:

File.which('notepad') # Works
File.which('notepad.exe') # Also works

--
Stefano

4

string#split accept a regular expression

path_list = ENV['PATH'].split(/[:;]/) # work s on Linus and Windows

HTH gfb

"Stefano Mioli" <stefano.mioli@gmail.com> wrote in message
news:AANLkTikcTzTvNbejW6JEL9_tmBAvKBqer7_W1X6p20M_@mail.gmail.com...

···

On Tue, Oct 19, 2010 at 10:08 PM, Daniel Berger <djberg96@gmail.com> wrote:

On Oct 19, 2:02 pm, Stefano Mioli <stefano.mi...@gmail.com> wrote:

The question is: is there some class in the Ruby library that knows
about this difference?

File::PATH_SEPARATOR

I'm asking this question because I need to figure out if a given
executable is in the path and, if it does, retrieve its full path.

require 'ptools'

File.which('ls') # => '/bin/ls'

Works on Windows, too, with or without an extension:

File.which('notepad') # Works
File.which('notepad.exe') # Also works

Many thanks, Dan.
I didn't know about ptools, and somehow I just saw File::SEPARATOR,
but not File::PATH_SEPARATOR.

--
Stefano

5

Well, it works. But it isn't helpful.

irb(main):002:0> 'C:\\foo;W::\\bar'.split(/[:;]/)
=> ["C", "\\foo", "W", "", "\\bar"]

Cheers

robert

···

On Wed, Oct 20, 2010 at 9:20 AM, GianFranco Bozzetti <gf.bozzetti@alice.it> wrote:

string#split accept a regular expression

path_list = ENV['PATH'].split(/[:;]/) # work s on Linus and Windows

HTH gfb

--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/