how to execute a command in scala?

Question

I want to execute this command "dot -Tpng overview.dot > overview.png ", which is used to generate an image by Graphviz.

The code in scala:

Process(Seq("dot -Tpng overview.dot > overview.png"))

It does not work. And I also want to open this image in scala. I work under Ubuntu. By default, images will be opened by image viewer. But I type "eog overview.png" in terminal, it reports error

** (eog:18371): WARNING **: The connection is closed

Thus, I do not know how to let scala open this image.

Thanks in advance.

Maybe this post stackoverflow.com/questions/5752330/scala-swing-image can help you in displaying the image. — Yang
– Yang, Commented Dec 6, 2013 at 16:30

senia · Accepted Answer · 2013-12-06 07:15:30Z

4

You can't redirect stdout using > in command string. You should use #> and #| operators. See examples in process package documentation.

This writes test into test.txt:

import scala.sys.process._
import java.io.File

// use scala.bat instead of scala on Windows
val cmd = Seq("scala", "-e", """println(\"test\")""") #> new File("test.txt")
cmd.!

In your case:

val cmd = "dot -Tpng overview.dot" #> new File("overview.png")
cmd.!

Or just this (since dot accepts output file name as -ooutfile):

"dot -Tpng overview.dot -ooverview.png".!

edited Dec 6, 2013 at 7:15

answered Dec 6, 2013 at 7:02

senia

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3 Comments

city Over a year ago

,thanks for your help. But now eclipse reports "overview.png: Permission denied". I think I should use command "su root". But I do not how to type in my password in code. Do you know how to solve this problem?

senia Over a year ago

@city: You should just specify filename id directory you can use. For instance: new File("/home/city/overview.png").

senia Over a year ago

@city: alternatively you could run scala from root.

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