I need to run a few lines of Ruby code from terminal, but I can't find the needed parameter for it.
Can you explain how to do this?
If Ruby is installed, then
ruby yourfile.rb
where yourfile.rb is the file containing the ruby code.
Or
irb
to start the interactive Ruby environment, where you can type lines of code and see the results immediately.
You can run ruby commands in one line with the -e flag:
ruby -e "puts 'hi'"
Check the man page for more information.
Related
Homebrew, ruby 2.0.0p648, nokogiri 1.6.7.2 are installed. When require 'nokogiri' there appears an error:
-bash: require: command not found
What's wrong?
Try running the script from the console/terminal shell like this:
ruby script_name.rb
You can also try adding this shebang line to the top of your .rb file:
#!/usr/bin/env ruby
This will auto-identify the script as Ruby when you try to run it directly in some shells. Also see:
Why is it better to use “#!/usr/bin/env NAME” instead of “#!/path/to/NAME” as my shebang?
what is the use of “#!/usr/local/bin/ruby -w” at the start of a ruby program
You're running your command in bash -- this is a Ruby command.
You can't run a Ruby command directly in bash. If you want to use Ruby at command line, open the Ruby shell irb.
$ irb
and then you'll see the prompt
2.3.0 :001 >
The first number indicates the Ruby version you are using. In my case it is Ruby 2.3.0. The second number is the command number.
Then you may type
require 'nokogiri'
and it surely work, if you have this gem installed.
I am using Mac OS X. I have two versions (2.1.5 and 2.0.0) of Ruby installed. The former installed at /another/.path/to/ruby (there is a dot before "path" to mimic the fact that the path contains a dot-headed directory in between), in addition to the default system one (version 2.0.0) at /usr/bin/ruby. I used rbenv to install Ruby.
After I manually set the PATH environment variable so the default ruby command will be found in another directory: /another/.path/to/ruby. Now I check
which -a ruby
It is using correct ruby first, as output.
/another/.path/to/ruby
/usr/bin/ruby
Now I create a script, rbs, with the first line of shebang specifying the ruby to use.
#!/usr/bin/env ruby
puts 'hey there'
Then I run
./rbs
it outputs 'hey there'. Good. Meanwhile, the Ruby is using the correct version.
/usr/bin/env ruby --version
as well as
ruby --version
both output 2.1.5. So it does great job to use the new version.
However, here is where the problem occurs: now I update rbs file to be:
#!/another/.path/to/ruby
puts 'hey there'
Note that I updated the shebang to use the absolute path to the desired ruby. then I run
./rbs
It outputs:
./rbs: line 2: puts: command not found
which is too weird;
but if I run
ruby ./rbs
it outputs 'hey there' as normal. It looks like the shebang works perfect using /usr/bin/env ruby, but not for absolute path for the newly install ruby?
Why is this? Is there a way to fix it so the updated script can still work by typing the following?
./rbs
Thanks!
The puts: command not found message indicates that your script is not being run by Ruby, but by the shell instead. So first, I would double-check your shebang line's syntax and path.
Second, note that rbenv uses shims that dynamically find and run the right version of ruby (and associated programs like gem, etc). But the shims are scripts, and scripts can't themselves be shebang interpreters; you have to find and use the actual path to the ruby executable (as output by rbenv which ruby).
On the other hand, since /usr/bin/env is an executable, you can always use something like #!/usr/bin/env ruby, which will work even if the ruby it finds in the path is itself a script.
I can't comment, (otherwise I'd add as a comment) but I think its worthwhile to add that the
#!/usr/bin/env ruby
MUST be the first line of the file. This tripped me up for a while.
source
which ruby - /usr/local/bin/ruby
.bash_profile has the above path
I have not left any trailing spaces before #!/usr/bin/env ruby in the ruby script
When I try to run sh ruby_script, it gives require: command not found. It is not able to recognize any of the ruby commands.
I checked all the other posts getting the same error, and fixed everything accordingly. What else could I be missing?
Running sh ruby_script is wrong. You must run ruby ruby_script instead. If the file is executable run ./ruby_script.
sh ruby_script is invoking the shell. Try either
/path/to/ruby_script
or
ruby /path/to/ruby_script
I need for a Ruby script to be run using an rvm-selected version. I cannot change how the script is invoked, but I can modify the script. The script starts with:
#!/usr/bin/env ruby
Now, based on some information I found (in this question, for example), I tried this:
#!/usr/bin/env rvm-shell ree-1.8.7-2012.02#gitorious
But this only gives me this error message:
/usr/bin/env: rvm-shell ree-1.8.7-2012.02#gitorious: No such file or directory
Now, rvm is available, because this works (but doesn't bring the required ruby/gemset):
#!/usr/bin/env rvm-shell
I've tried this as well:
#!/usr/local/rvm/bin/rvm-shell ree-1.8.7-2012.02#gitorious
But this doesn't bring in the environment ("gem", which is only installed inside that gemset, is not available, for example). If I run that on the command line itself, it does open a shell with the proper environment.
So, has anyone done something like this? How can I fix it?
Does this work?
#!/location/of/rvm/folder/rubies/ree-1.8.7-2012.02#gitorious/bin/ruby
I've set everything up that I need on my Mac (Ruby, Rails, Homebrew, Git, etc), and I've even written a small program. Now, how do I execute it in Terminal? I wrote the program in Redcar and saved it as a .rb, but I don't know how to execute it through Terminal. I want to run the program and see if it actually works. How do I do this?
Just call: ruby your_program.rb
or
start your program with #!/usr/bin/env ruby,
make your file executable by running chmod +x your_program.rb
and do ./your_program.rb some_param
Open your terminal and open folder where file is saved.
Ex /home/User1/program/test.rb
Open terminal
cd /home/User1/program
ruby test.rb
format or test.rb
class Test
def initialize
puts "I love India"
end
end
# initialize object
Test.new
output
I love India
Assuming ruby interpreter is in your PATH (it should be), you simply run
ruby your_file.rb
To call ruby file use : ruby your_program.rb
To execute your ruby file as script:
start your program with #!/usr/bin/env ruby
run that script using ./your_program.rb param
If you are not able to execute this script check permissions for file.
Just invoke ruby XXXXX.rb in terminal, if the interpreter is in your $PATH variable.
( this can hardly be a rails thing, until you have it running. )
For those not getting a solution for older answers, i simply put my file name as the very first line in my code.
like so
#ruby_file_name_here.rb
puts "hello world"
Although its too late to answer this question, but still for those guys who came here to see the solution of same problem just like me and didn't get a satisfactory answer on this page, The reason is that you don't have your file in the form of .rb extension. You most probably have it in simple text mode. Let me elaborate.
Binding up the whole solution on the page, here you go (assuming you filename is abc.rb or at least you created abc):
Type in terminal window:
cd ~/to/the/program/location
ruby abc.rb
and you are done
If the following error occurs
ruby: No such file or directory -- abc.rb (LoadError)
Then go to the directory in which you have the abc file, rename it as abc.rb
Close gedit and reopen the file abc.rb. Apply the same set of commands and success!
In case someone is trying to run a script in a RAILS environment,
rails provide a runner to execute scripts in rails context via
rails runner my_script.rb
More details here:
https://guides.rubyonrails.org/command_line.html#rails-runner
Open Terminal
cd to/the/program/location
ruby program.rb
or add #!/usr/bin/env ruby in the first of your program (script tell that this is executed using Ruby Interpreter)
Open Terminal
cd to/the/program/location
chmod 777 program.rb
./program.rb
You can run ruby code just passing -e option
ruby -e 'x = Time.now; puts x;'
Output will be:
2022-06-22 15:55:06 +0500