Execute a system command and return its output

Summary

The system macro executes an operating system command and returns its standard output. The command runs in the project’s base directory. The build fails if the command returns a non-zero exit code.

Syntax 

${system;<command>[;<input>]}

Parameters

  • command - The system command to execute
  • input (optional) - Text to send to the command’s standard input

Behavior

  • Executes the command in the project base directory
  • On Windows, automatically wraps command with cmd /c
  • Captures and returns standard output (trimmed)
  • If input is provided, writes it to the command’s stdin
  • Returns empty string and generates error if command fails
  • Build fails on non-zero exit codes

Examples

Get Git commit hash:

Git-Commit: ${system;git rev-parse HEAD}

Get current date:

Build-Date: ${system;date}

Execute command with input:

${system;wc -l;line1\nline2\nline3}

Get Maven version:

mvn.version=${system;mvn --version}

List files:

files=${system;ls -la}

Use Cases

  • Embedding command output in manifests
  • Getting version control information
  • Capturing build environment details
  • Running custom build scripts
  • Platform-specific build information
  • Integration with external tools

Notes

  • Security Warning: Be cautious with user input in commands
  • Commands run in the project base directory
  • Windows commands are automatically wrapped with cmd /c
  • Standard output is captured and trimmed
  • Standard error is not captured
  • Build fails on command failure
  • See also: ${system-allow-fail} for non-failing variant
  • May be disabled in restricted execution modes

TODO Needs review - AI Generated content

See test cases in MacroTestsForDocsExamples.java