CODEWITHSUNDEEP
scala
MrE
MrE

Reputation: 20788

What does Some(string.!!) mean in Scala?

I have 

val str = s"""/bin/bash -c 'some command'"""
job = Some(str.!!)

It is meant to execute the bash command I assume.

Can someone explain this syntax? Googling for '.!!' doesn't help much neither does 'dot exclamation exclamation' so I hope someone can explain this one and/or point me to the doc.

The job doesn't run and I'm trying to debug the code, but when i put this in a 

try {
   command = Some(str.!!)
} 
catch { 
case e:Exception => 
  println(e.toString)
}

e is actually not an Exception for some reason... Trying to figure what this really does and how to find what is happening.

Upvotes: 8

Views: 2688

Answers (1)

Mark
Mark

Reputation: 1181

There is an implicit conversion from String to ProcessBuilder. When you import scala.sys.process._ then scala will automatically perform the conversion when needed, thus making the method !! available on String instances. You can find the methods of ProcessBuilder here: http://www.scala-lang.org/api/current/index.html#scala.sys.process.ProcessBuilder

The documentation for !! says that "If the exit code is non-zero, an exception is thrown." It appears that bash in this case does return 0, so the command was for some reason successful.

Upvotes: 8

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