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| <title>Exec Task</title> |
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| <h2><a name="exec">Exec</a></h2> |
| <h3>Description</h3> |
| <p>Executes a system command. When the <i>os</i> attribute is specified, then |
| the command is only executed when Ant is run on one of the specified operating |
| systems.</p> |
| |
| <p>Note that you cannot interact with the forked program, the only way |
| to send input to it is via the input and inputstring attributes.</p> |
| |
| <h4>Cygwin Users</h4> |
| <p>In general the <exec> task will not understand paths such as /bin/sh for |
| the executable parameter. This is because the Java VM in which Ant is running is a |
| Windows executable and is not aware of Cygwin conventions. |
| </p> |
| |
| <h4>OpenVMS Users</h4> |
| <p>The command specified using <code>executable</code> and |
| <code><arg></code> elements is executed exactly as specified |
| inside a temporary DCL script. This has some implications: |
| <ul> |
| <li>paths have to be written in VMS style</li> |
| <li>if your <code>executable</code> points to a DCL script remember to |
| prefix it with an <code>@</code>-sign |
| (e.g. <code>executable="@[FOO]BAR.COM"</code>), just as you would in a |
| DCL script</li> |
| </ul> |
| For <code><exec></code> to work in an environment with a Java VM |
| older than version 1.4.1-2 it is also <i>required</i> that the logical |
| <code>JAVA$FORK_SUPPORT_CHDIR</code> is set to <code>TRUE</code> in |
| the job table (see the <i>JDK Release Notes</i>).</p> |
| |
| <p>Please note that the Java VM provided by HP doesn't follow OpenVMS' |
| conventions of exit codes. If you run a Java VM with this task, the |
| task may falsely claim that an error occured (or silently ignore an |
| error). Don't use this task to run <code>JAVA.EXE</code>, use a |
| <code><java></code> task with the <code>fork</code> attribute |
| set to <code>true</code> instead as this task will follow the VM's |
| interpretation of exit codes.</p> |
| |
| <h3>Parameters</h3> |
| <table border="1" cellpadding="2" cellspacing="0"> |
| <tr> |
| <td valign="top"><b>Attribute</b></td> |
| <td valign="top"><b>Description</b></td> |
| <td align="center" valign="top"><b>Required</b></td> |
| </tr> |
| <tr> |
| <td valign="top">command</td> |
| <td valign="top">the command to execute with all command line |
| arguments. <b>deprecated, use executable and nested |
| <code><arg></code> elements instead</b>.</td> |
| <td align="center" rowspan="2">Exactly one of the two.</td> |
| </tr> |
| <tr> |
| <td valign="top">executable</td> |
| <td valign="top">the command to execute without any command line |
| arguments.</td> |
| </tr> |
| <tr> |
| <td valign="top">dir</td> |
| <td valign="top">the directory in which the command should be executed.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">os</td> |
| <td valign="top">list of Operating Systems on which the command may be |
| executed. If the current OS's name is contained in this list, the command will |
| be executed. The OS's name is determined by the Java Virtual machine and is set |
| in the "os.name" system property.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">spawn</td> |
| <td valign="top">whether or not you want the command to be spawned<br/> |
| Default is false.<br> |
| If you spawn a command, its output will not be logged by ant.<br/> |
| The input, output, error, and result property settings are not active when spawning a process.<br> |
| <em>since Ant 1.6</em> |
| </td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">output</td> |
| <td valign="top">Name of a file to which to write the output. If the error stream |
| is not also redirected to a file or property, it will appear in this output.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">error</td> |
| <td valign="top">The file to which the standard error of the |
| command should be redirected. <em>since Ant 1.6</em></td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">logError</td> |
| <td valign="top">This attribute is used when you wish to see error output in Ant's |
| log and you are redirecting output to a file/property. The error |
| output will not be included in the output file/property. If you |
| redirect error with the "error" or "errorProperty" |
| attributes, this will have no effect. <em>since Ant 1.6</em></td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">append</td> |
| <td valign="top">Whether output and error files should be appended to or overwritten. |
| Defaults to false.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">outputproperty</td> |
| <td valign="top">The name of a property in which the output of the |
| command should be stored. Unless the error stream is redirected to a separate |
| file or stream, this property will include the error output.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">errorproperty</td> |
| <td valign="top">The name of a property in which the standard error of the |
| command should be stored. <em>since Ant 1.6</em></td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">input</td> |
| <td valign="top">A file from which the executed command's standard input |
| is taken. This attribute is mutually exclusive with the |
| inputstring attribute. <em>since Ant 1.6</em></td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">inputstring</td> |
| <td valign="top">A string which serves as the input stream for the |
| executed command. This attribute is mutually exclusive with the |
| input attribute. <em>since Ant 1.6</em></td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">resultproperty</td> |
| <td valign="top">the name of a property in which the return code of the |
| command should be stored. Only of interest if failonerror=false.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">timeout</td> |
| <td valign="top">Stop the command if it doesn't finish within the |
| specified time (given in milliseconds).</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">failonerror</td> |
| <td valign="top">Stop the buildprocess if the command exits with a |
| return code signaling failure. Defaults to false.</td> |
| <td align="center" valign="top">No</td> |
| </tr> |
| <tr> |
| <td valign="top">failifexecutionfails</td> |
| <td valign="top">Stop the build if we can't start the program. |
| Defaults to true. </td> |
| <td align="center" valign="top">No</td> |
| </tr> <tr> |
| <td valign="top">newenvironment</td> |
| <td valign="top">Do not propagate old environment when new environment |
| variables are specified.</td> |
| <td align="center" valign="top">No, default is <i>false</i></td> |
| </tr> |
| <tr> |
| <td valign="top">vmlauncher</td> |
| <td valign="top">Run command using the Java VM's execution facilities |
| where available. If set to false the underlying OS's shell, |
| either directly or through the antRun scripts, will be used. |
| Under some operating systems, this gives access to facilities |
| not normally available through the VM including, under Windows, |
| being able to execute scripts, rather than their associated |
| interpreter. If you want to specify the name of the |
| executable as a relative path to the directory given by the |
| dir attribute, it may become necessary to set vmlauncher to |
| false as well.</td> |
| <td align="center" valign="top">No, default is <i>true</i></td> |
| </tr> |
| <tr> |
| <td valign="top">resolveExecutable</td> |
| <td valign="top">When this attribute is true, the name of the executable |
| if resolved firstly against the project basedir and |
| if that does not exist, against the execution |
| directory if specified. On Unix systems, if you only |
| want to allow execution of commands in the user's path, |
| set this to false. <em>since Ant 1.6</em></td> |
| <td align="center" valign="top">No, default is <i>false</i></td> |
| </tr> |
| </table> |
| <h3>Examples</h3> |
| <blockquote> |
| <pre> |
| <exec dir="${src}" executable="cmd.exe" os="Windows 2000" output="dir.txt"> |
| <arg line="/c dir"/> |
| </exec></pre> |
| </blockquote> |
| <h3>Parameters specified as nested elements</h3> |
| <h4>arg</h4> |
| <p>Command line arguments should be specified as nested |
| <code><arg></code> elements. See <a |
| href="../using.html#arg">Command line arguments</a>.</p> |
| <h4><a name="env">env</a></h4> |
| <p>It is possible to specify environment variables to pass to the |
| system command via nested <code><env></code> elements.</p> |
| <table border="1" cellpadding="2" cellspacing="0"> |
| <tr> |
| <td valign="top"><b>Attribute</b></td> |
| <td valign="top"><b>Description</b></td> |
| <td align="center" valign="top"><b>Required</b></td> |
| </tr> |
| <tr> |
| <td valign="top">key</td> |
| <td valign="top">The name of the environment variable.</td> |
| <td align="center" valign="top">Yes</td> |
| </tr> |
| <tr> |
| <td valign="top">value</td> |
| <td valign="top">The literal value for the environment variable.</td> |
| <td align="center" rowspan="3">Exactly one of these.</td> |
| </tr> |
| <tr> |
| <td valign="top">path</td> |
| <td valign="top">The value for a PATH like environment |
| variable. You can use ; or : as path separators and Ant will |
| convert it to the platform's local conventions.</td> |
| </tr> |
| <tr> |
| <td valign="top">file</td> |
| <td valign="top">The value for the environment variable. Will be |
| replaced by the absolute filename of the file by Ant.</td> |
| </tr> |
| </table> |
| |
| <h3>Errors and return codes</h3> |
| By default the return code of a <exec> is ignored; when you set |
| <code>failonerror="true"</code> then any return code signaling failure |
| (OS specific) causes the build to fail. Alternatively, you can set |
| <code>resultproperty</code> to the name of a property and have it assigned to |
| the result code (barring immutability, of course). |
| <p> |
| If the attempt to start the program fails with an OS dependent error code, |
| then <exec> halts the build unless <code>failifexecutionfails</code> |
| is set to <code>false</code>. You can use that to run a program if it exists, but |
| otherwise do nothing. |
| <p> |
| What do those error codes mean? Well, they are OS dependent. On Windows |
| boxes you have to look in include\error.h in your windows compiler or wine files; |
| error code 2 means 'no such program', which usually means it is not on the path. |
| Any time you see such an error from any ant task, it is usually not an ant bug, |
| but some configuration problem on your machine. |
| |
| <h3>Examples</h3> |
| <blockquote><pre> |
| <exec executable="emacs"> |
| <env key="DISPLAY" value=":1.0"/> |
| </exec> |
| </pre></blockquote> |
| <p>starts <code>emacs</code> on display 1 of the X Window System.</p> |
| |
| <blockquote><pre> |
| <exec ... > |
| <env key="PATH" path="${java.library.path}:${basedir}/bin"/> |
| </exec> |
| </pre></blockquote> |
| <p>adds <code>${basedir}/bin</code> to the <code>PATH</code> of the |
| system command.</p> |
| |
| <blockquote><pre> |
| <property name="browser" location="C:/Programme/Internet Explorer/iexplore.exe"/> |
| <property name="file" location="ant/docs/manual/index.html"/> |
| |
| <exec executable="${browser}" spawn="true"> |
| <arg value="${file}"/> |
| </exec> |
| </pre></blockquote> |
| <p>Starts the <i>${browser}</i> with the specified <i>${file}</i> and end the |
| ant process. The browser will let be open.</p> |
| |
| |
| <p><b>Note:</b> Although it may work for you to specify arguments using |
| a simple arg-element and separate them by spaces it may fail if you switch to |
| a newer version of the JDK. JDK < 1.2 will pass these as separate arguments |
| to the program you are calling, JDK >= 1.2 will pass them as a single |
| argument and cause most calls to fail.</p> |
| <p><b>Note2:</b> If you are using Ant on Windows and a new DOS-Window pops up |
| for every command which is executed this may be a problem of the JDK you are using. |
| This problem may occur with all JDK's < 1.2.</p> |
| <p> |
| <b>Timeouts: </b> If a timeout is specified, when it is reached the |
| sub process is killed and a message printed to the log. The return |
| value of the execution will be "-1", which will halt the build if |
| <tt>failonerror=true</tt>, but be ignored otherwise. |
| <hr> |
| <p align="center">Copyright © 2000-2003 Apache Software Foundation. All rights |
| Reserved.</p> |
| |
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