# [bld](https://rife2.com/bld) Command Line Execution Extension
[](https://opensource.org/licenses/Apache-2.0)
[](https://www.oracle.com/java/technologies/javase/jdk17-archive-downloads.html)
[](https://rife2.com/bld)
[](https://repo.rife2.com/#/releases/com/uwyn/rife2/bld-exec)
[](https://repo.rife2.com/#/snapshots/com/uwyn/rife2/bld-exec)
[](https://github.com/rife2/bld-exec/actions/workflows/bld.yml)
To install, please refer to the [extensions documentation](https://github.com/rife2/bld/wiki/Extensions).
To execute a command at the command line, add the following to your build file:
```java
@BuildCommand
public void startServer() throws Exception {
new ExecOperation()
.fromProject(this)
.command("./start.sh", "--port", "8080")
.execute();
}
```
### Failure Modes
Use the `fail` function to specify whether data returned to the standard streams and/or an abnormal exit value
constitute a failure.
```java
@BuildCommand
public void startServer() throws Exception {
final List cmds;
if (System.getProperty("os.name").toLowerCase().contains("windows")) {
cmds = List.of("cmd", "/c", "stop.bat");
} else {
cmds = List.of("./stop.sh");
}
new ExecOperation()
.fromProject(this)
.command(cmds)
.fail(ExecFail.STDERR)
.execute();
}
```
The following predefined values are available:
| Name | Failure When |
|:------------------|:-----------------------------------------------------------------|
| `ExecFail.EXIT` | Exit value > 0 |
| `ExecFail.NORMAL` | Exit value > 0 or any data to the standard error stream (stderr) |
| `ExecFail.OUTPUT` | Any data to the standard output stream (stdout) or stderr. |
| `ExecFail.STDERR` | Any data to stderr. |
| `ExecFail.STDOUT` | Any data to stdout. |
| `ExecFail.ALL` | Any of the conditions above. |
| `ExecFail.NONE` | Never fails. |
`ExecFail.NORMAL` is the default value.
## Working Directory
You can also specify the working directory:
```java
@BuildCommand
public void startServer() throws Exception {
new ExecOperation()
.fromProject(this)
.command("touch", "foo.txt")
.workDir(System.getProperty("java.io.tmpdir"))
.execute();
}
```