I'd like to know how to pass arguments to a golfscript program from the command line. I'm using ruby interpreter that I downloaded from golfscript.com. From what I understood from googling a bit, in ruby you pass arguments like this ruby ./program.rb 4, but doing ruby ./golfscript.rb prnt.gs 4 doesn't work (prints an empty string).
In golfscript the arguments are supposed to be made into a string and pushed to the stack.
prnt.gs's code is just p (it's supposed to print the top of the stack - the argument).
What am I doing wrong?
try running it like this:
>echo 4 | ruby golfscript.rb prnt.gs
Related
I'm trying to execute a Ruby script file.
Assuming the input is a string that contains the file content.
What are the possible ways? taking into considerations that I need to keep the output of the executed file whether stdout or not separated from the Main script.
As an example of what I'm trying to do is have a function called execute(code)
Then calling execute('4 + 5') would return 9 although I can write a whole Ruby script in the place of '4 + 5'.
If anyone can forward me to any related tutorials or books, I'd be thankful :)
You can call shell commands in Ruby, it's as simple and intuitive as surrounding your desired command in backticks.
The output gets returned, so just save it to a variable:
script1.rb:
puts "asdf"
script2.rb:
output = `ruby script1.rb`
puts output
"asdf"
I question what exactly it is you're trying to do, though. Because this is totally unintuitive and roundabout. Are you sure you aren't just looking for a module or something?
I tried passing variables to a gnuplot script as explained here, but I only get an error message:
Non-numeric string found where a numeric expression was expected
I am using gnuplot on Windows 7.
I had a friend try the same thing on Linux Mint and it works like a charm there.
Is this functionality just not included in the windows version of gnuplot or can I change something to accomplish the same thing? Is there another way to do this?
My script:
print "p0=$0 p1=$1 p2=$2 p3=$3 p4=$4 p5=$5 p6=$6 p7=x$7x"
How i call it:
gnuplot> call 'calltest.gp' "abcd" 1.2 + "'quoted'" -- "$2"
I use gnuplot Version 5.0 patchlevel 0.
The parameters to call must be strings. While conversion of numbers to strings works on Linux, it makes problems on Windows:
Wrong:
call 'script.gp' 'string' 12
Correct:
call 'script.gp' 'string' '12'
You must also note, that the call behavior was changed with version 5. Now, ARG0 contains the naming of the called script, and the parameters are contained in variables ARG1, ARG2 etc.
I have a parse a command line argument in shell script as follows:
cmd --a=hello world good bye --b=this is bash script
I need the parse the arguments of "a" i.e "hello world ..." which are seperated by whitespace into an array.
i.e a_input() array should contain "hello", "world", "good" and "bye".
Similarly for "b" arguments as well.
I tried it as follows:
--a=*)
a_input={1:4}
a_input=$#
for var in $a_input
#keep parsing until next --b or other argument is seen
done
But the above method is crude. Any other work around. I cannot use getopts.
The simplest solution is to get your users to quote the arguments correctly in the first place.
Barring that you can manually loop until you get to the end of the arguments or hit the next --argument (but that means you can't include a word that starts with -- in your argument value... unless you also do valid-option testing on those in which you limit slightly fewer -- words).
Adding to Etan Reisners answer, which is absolutely correct:
I personally find bash a bit cumbersome, when array/string processing gets more complex, and if you really have the strange requirement, that the caller should not be required to use quotes, I would here write an intermediate script in, say, Ruby or Perl, which just collects the parameters in a proper way, wraps quoting around them, and passes them on to the script, which originally was supposed to be called - even if this costs an additional process.
For example, a Ruby One-Liner such as
system("your_bash_script here.sh '".(ARGV.join(' ').split(' --').select {|s| s.size>0 }.join("' '"))."'")
would do this sanitizing and then invoke your script.
I'm writing a simple command line gem.
The library that does the actual work was developed with rspec and so far that works.
I'm trying to test the command line portion with Aruba/Cucumber, but I've come across some strange behaviour.
Just to test this, I've got a the binary file to puts ARGV, and I've got test files in tmp/aruba
When I run bundle exec gem_name tmp/aruba/*.* I am presented with the list of shell expanded file names.
Now my features file has:
Given files to work on # I set up files in tmp/aruba in this step
When I run `gem_name *.*` # standard step
Then the output should contain "Wibble"
The last step is obviously going to fail, but it shows me a diff between what it expects and the actual output. Rather than seeing a list of shell expanded filenames, all I get is "*.*"
So I'm left in the position of having an app that actually works as expected, but I can't get the tests to pass. I could take the "." and generate the list of files from there, but then I'm writing extra production code just to get the app to work under test - which I don't think is the correct way to go about it. And all because shell expansion isn't happening.
If you look at my profile, you'll see that Ruby isn't my main bag, feel free to point me at any resources that I may have missed about this, but is this just me missing something, or expected behaviour that somebody knows how to work around?
After a little digging in the Aruba source I figured out that the When I run step ends up in a code block like this:
def run!(&block)
#process = ChildProcess.build(*shellwords(#cmd))
...
begin
#process.start
...
Further digging into ChildProcess ends up here:
def launch_process
...
begin
exec(*#args)
...
And therein lies the problem. exec does not do shell expansion when the argument list is split into multiple array elements:
If exec is given a single argument, that argument is
taken as a line that is subject to shell expansion before being
executed. If multiple arguments are given, the second and
subsequent arguments are passed as parameters to command with no
shell expansion.
However playing with shellwords a bit we find:
Shellwords.shellwords('gem_name *.*')
=> ["gem_name", "*.*"] # No good
Shellwords.shellwords('"gem_name *.*"')
=> ["gem_name *.*"] # Aha!
Therefore the solution might be as simple as:
When I run `"gem_name *.*"`
If that doesn't work then you are pretty much out of luck. I would suggest you expand the file names manually since you're not really testing shell expansion here - we know that works: you are testing multiple arguments.
Therefore you should instead do:
When I run `gem_name your_file1 your_file2 your_file3`
I'm using pry and I want to capture, and work with output of a shell command.
For example, If I run
pry(main)> .ls
I want to get the list of files into an array that I can work with in Ruby.
How can I do this?
This is a pretty old question but I'll answer it anyways. There are two primary methods of getting data out of pry commands. The first is if the command sets the keep_retval option to true, which the shell command does not. The second, is to use the virtual pipe. In your example this can be done as:
fizz = []
.ls | {|listing| fizz = listing.split("\n")} # can also be written as
.ls do |listing|
fizz = listing.split("\n")
end
I assume it's some kind of pry's magic ;-)
After quick look at what's happening (I didn't look at pry's source), you might want to use this:
`ls`.split("\n")
or
Dir['./*']
What's good about this solution is that it will work outside of pry