Separator in $PATH

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.

On Oct 19, 2:02pm, Stefano M. [email protected] wrote:

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 Tue, Oct 19, 2010 at 10:08 PM, Daniel B. removed_email_a[email protected]
wrote:

On Oct 19, 2:02pm, Stefano M. [email protected] wrote:

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.

string#split accept a regular expression

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

HTH gfb

“Stefano M.” [email protected] wrote in message
news:[email protected]
On Tue, Oct 19, 2010 at 10:08 PM, Daniel B. [email protected]
wrote:

On Oct 19, 2:02 pm, Stefano M. [email protected] wrote:

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.

On Wed, Oct 20, 2010 at 9:20 AM, GianFranco B.
[email protected] wrote:

string#split accept a regular expression

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

HTH gfb

Well, it works. But it isn’t helpful.

irb(main):002:0> ‘C:\foo;W::\bar’.split(/[:;]/)
=> [“C”, “\foo”, “W”, “”, “\bar”]

Cheers

robert

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