1 /* 2 * Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 import java.io.File; 25 import java.util.HashMap; 26 import java.util.Map; 27 28 /** 29 * Utility class for finding the command on the current system 30 */ 31 public class UnixCommands { 32 33 public static final boolean isUnix = ! System.getProperty("os.name").startsWith("Windows"); 34 public static final boolean isLinux = System.getProperty("os.name").startsWith("Linux"); 35 36 private static final String[] paths = {"/bin", "/usr/bin"}; 37 38 private static Map<String,String> nameToCommand = new HashMap<>(16); 39 40 /** 41 * Throws Error unless every listed command is available on the system 42 */ 43 public static void ensureCommandsAvailable(String... commands) { 44 for (String command : commands) { 45 if (findCommand(command) == null) { 46 throw new Error("Command '" + command + "' not found; bailing out"); 47 } 48 } 49 } 50 51 /** 52 * If the path to the command could be found, returns the command with the full path. 53 * Otherwise, returns null. 54 */ 55 public static String cat() { return findCommand("cat"); } 56 public static String sh() { return findCommand("sh"); } 57 public static String kill() { return findCommand("kill"); } 58 public static String sleep() { return findCommand("sleep"); } 59 public static String tee() { return findCommand("tee"); } 60 public static String echo() { return findCommand("echo"); } 61 62 public static String findCommand(String name) { 63 if (nameToCommand.containsKey(name)) { 64 return nameToCommand.get(name); 65 } 66 String command = findCommand0(name); 67 nameToCommand.put(name, command); 68 return command; 69 } 70 71 private static String findCommand0(String name) { 72 for (String path : paths) { 73 File file = new File(path, name); 74 if (file.canExecute()) { 75 return file.getPath(); 76 } 77 } 78 return null; 79 } 80 }