How can I get the Ruby version from within a Ruby script?

Ruby
1

I want to log the current Ruby version to a log file along with the
script version, but I don’t know how to get the Ruby version from
within a running script.

I tried:
puts system(“ruby -v”)

but that only returns “true” from within a script. (I see the correct
output when I run it in IRB, but the script doesn’t capture that.)

I also tried :
puts Config::CONFIG[“ruby_version”]

but that returns “1.8” and I would like “1.8.x”.

Any suggestions? Please let me know. Thanks.

2

Paul schrieb:

I want to log the current Ruby version to a log file along with the
script version, but I don’t know how to get the Ruby version from
within a running script.

Just use constant RUBY_VERSION.

puts RUBY_VERSION
=> 1.8.6

3

On Jul 16, 2007, at 9:55 AM, Paul wrote:

I also tried :
puts Config::CONFIG[“ruby_version”]

but that returns “1.8” and I would like “1.8.x”.

Any suggestions? Please let me know. Thanks.

the constant VERSION will return the version number (only)
puts “Ruby version #{VERSION}”

4

Alle lunedì 16 luglio 2007, Paul ha scritto:

I also tried :
puts Config::CONFIG[“ruby_version”]

but that returns “1.8” and I would like “1.8.x”.

Any suggestions? Please let me know. Thanks.

You can try

puts(RUBY_VERSION)

By the way, if you need to get the output of an external command, you
need to
use cmd, instead of system(“cmd”).

Stefano

5

On Jul 16, 2007, at 8:57 AM, Axel E. wrote:

this works for me:

result= ruby -v
p ‘my result’
p result

Unfortunately, this grabs the version of some Ruby, not necessarily
the one currently running. The RUBY_VERSION constant is what you
probably want.

Paul K. (A different Paul than the OP)

6

Paul,

this works for me:

result= ruby -v
p ‘my result’
p result

Best regards,

Axel

7

On 16.07.2007 19:16, Paul wrote:

On Jul 16, 11:13 am, Phil M. wrote:

Just use constant RUBY_VERSION.

puts RUBY_VERSION
=> 1.8.6

That’s perfect! Thank you.

I don’t know why Google didn’t turn that up anywhere. I even checked
the Pickaxe book but I didn’t find it under “V” for ‘version’.

Since the version is a good candidate for a constant you can try this:

Robert@Babelfish2 ~
$ ruby -e ‘Object.constants.sort.each {|c| cv=Object.const_get©; print
c, “=”, cv, “\n” unless Module === cv}’
ARGF=ARGF
ARGV=
ENV=ENV
FALSE=false
NIL=nil
PLATFORM=i386-cygwin
RELEASE_DATE=2007-03-13
RUBY_PATCHLEVEL=0
RUBY_PLATFORM=i386-cygwin
RUBY_RELEASE_DATE=2007-03-13
RUBY_VERSION=1.8.6
STDERR=#IO:0x100362d0
STDIN=#IO:0x100362f8
STDOUT=#IO:0x100362e4
TOPLEVEL_BINDING=#Binding:0x100302a4
TRUE=true
VERSION=1.8.6

Robert@Babelfish2 ~
$

Or just use IRB.

Kind regards

robert

8

On Jul 16, 11:13 am, Phil M. wrote:

Just use constant RUBY_VERSION.

puts RUBY_VERSION
=> 1.8.6

That’s perfect! Thank you.

I don’t know why Google didn’t turn that up anywhere. I even checked
the Pickaxe book but I didn’t find it under “V” for ‘version’.

Cheers!