Check if executable command exists using ant

问题

Is it possible to check if a command exists as part of an ant task. For example, I want to ensure the "yasm" command is present as part of the ant task. Is this possible? If so, can you provide an example?

回答1:

The best way I can think of to do this is by using the available task combined with an if in a subsequent target. If you take a look at that task page you will see that you can check to see if something exists then set a property. For example:

<available file="/path/to/my/file" type="file" property="file.present"/>

Then in the target you would say something like <target name='foo' if='file.present'>

That doesn't check for executable permissions but it will get much closer. If a task exists to check for the executable permission specifically you would still probably combine it with the if in the target.

---

Original answer

It is better to use the ant copy task instead of trying to execute cp yourself. This keeps its platform independent.

<copy todir"/some/target">
   <fileset dir="/some/src"/>
</copy>

More usage on the Ant documentation for the copy task.

回答2:

The following idiom can be used to find an executable somewhere in the environment's PATH.

  <property environment="env" /> 
  <available file="commandname"  
             filepath="${env.PATH}"  
             property="commandname.present"/>

来源：https://stackoverflow.com/questions/16556746/check-if-executable-command-exists-using-ant