Execute

public Process execute()

Véase la documentación de String sobre execute():

Executes the given string as a command line process. For more control over the process mechanism in JDK 1.5 you can use java.lang.ProcessBuilder.

Returns: the Process which has just started for this command line string

Sigue un ejemplo de uso:

generaciondecodigos@nereida:~/src/groovy/processes$ cat -n retcode.groovy
     1  #!/usr/bin/env groovy
     2  sarg = args.join(' ')
     3  def command = """
     4  ls $sarg
     5  """// Create the String
     6  def proc = command.execute()
     7  proc.waitFor()
     8
     9  println "return code: ${proc.exitValue()}"
    10  println "stderr: ${proc.err.text}"
    11  println "stdout: ${proc.in.text}"

Veamos los resultados de dos ejecuciones:

generaciondecodigos@nereida:~/src/groovy/processes$ ./retcode.groovy -l *.groovy
return code: 0
stderr:
stdout: -rwxr-xr-x 1 generaciondecodigos generaciondecodigos 177 2009-11-18 11:00 cat2.groovy
-rwxr-xr-x 1 generaciondecodigos generaciondecodigos 172 2009-11-18 11:14 cat.groovy
-rwxr-xr-x 1 generaciondecodigos generaciondecodigos 351 2009-11-18 10:52 grooshEx2.groovy
-rwxr-xr-x 1 generaciondecodigos generaciondecodigos 145 2009-11-18 10:36 grooshEx.groovy
-rwxr-xr-x 1 generaciondecodigos generaciondecodigos 274 2010-03-01 11:19 retcode.groovy

generaciondecodigos@nereida:~/src/groovy/processes$ ./retcode.groovy doesnotexist
return code: 2
stderr: ls: no se puede acceder a doesnotexist: No existe el fichero ó directorio

stdout:

Argumentos que Contienen Blancos

Take care if you wish to pass a quoted argument that contains white space – it will be split into multiple arguments, e.g.:

generaciondecodigos@nereida:~/src/groovy/processes$ ls -l 'a file'
-rw-r--r-- 1 generaciondecodigos generaciondecodigos 3 2010-03-01 11:23 a file
generaciondecodigos@nereida:~/src/groovy/processes$ ./retcode.groovy 'a file'
return code: 2
stderr: ls: no se puede acceder a a: No existe el fichero ó directorio
ls: no se puede acceder a file: No existe el fichero ó directorio

stdout:

The call """executable "first with space" second""".execute() invokes executable with the following arguments:

    * arg1 = "first
    * arg2 = with
    * arg3 = space"
    * arg4 = second

In such a case, you may prefer to use one of the array or list of String variations, e.g.:

["executable", "first with space", "second"].execute()

Veamos un ejemplo:

~/Lgroovy/files$ ls -l 'a file'
-rw-r--r--  1 casianorodriguezleon  staff  28 16 abr 06:10 a file
~/Lgroovy/files$ groovysh
Groovy Shell (1.6.5, JVM: 1.6.0_17)
Type 'help' or '\h' for help.
-----------------------------------------------------------------------------------------------------------------------------------------------------
groovy:000> r = ['ls', 'a file'].execute()
===> java.lang.UNIXProcess@50a69b6b
groovy:000> r.waitFor()
===> 0
groovy:000> r.exitValue()
===> 0
groovy:000> r.err.text
===> 
groovy:000> r.in.text
===> a file

Como método de una lista execute nos permite introducir Expresiones shell en los argumentos:

groovy:000> p=['bash', '-c', 'ls -l|head -4'].execute()
===> java.lang.UNIXProcess@27af8502
groovy:000> p.waitFor()
===> 0
groovy:000> p.in.text
===> total 28
-rw-r--r-- 1 lhp lhp    0 2010-04-21 10:51 cat -n
-rw-r--r-- 1 lhp lhp  422 2010-04-21 11:03 feedProcess.groovy
-rw-r--r-- 1 lhp lhp  140 2010-04-21 11:11 input.txt