@Field
    public void setFilePath(String fileCommandPath) {
        //this opens up a potential command vulnerability.
        //Don't ever let an untrusted user set this.
        this.fileCommandPath = fileCommandPath;
        checkHasFile(this.fileCommandPath);
    }
@param input    document input stream, or <code>null</code>
@param metadata input metadata for the document
@return mime as identified by the file command or application/octet-stream otherwise
@throws IOException
tika-core/src/main/java/org/apache/tika/detect/FileCommandDetector.java