A function for correctly parsing CLI commands with quotes and escape characters, on Windows, Linux, and OS X.

ParseCLI.java

/**************************************************************************
 Public Domain
 To the extent possible under law, Aaron Madlon-Kay has waived all
 copyright and related or neighboring rights to this work.
 This work is published from: Japan
 **************************************************************************/

package org.amk;

import java.util.ArrayList;
import java.util.List;

public class ParseCLI {

    /**
     * Parse a command line string into arguments, interpreting
     * double and single quotes as Bash does.
     * 
     * Use '\' to escape whitespace (outside of quotes only)
     * and to escape double quotes (inside double quotes only).
     * 
     * This is suitable for parsing arguments to be passed to
     * {@link Runtime#exec(String[])}, on Windows, Linux, and
     * OS X.
     * 
     * @param cmd Command string
     * @return Array of arguments
     */
    public static String[] parseCLICommand(String cmd) {
        cmd = cmd.trim();
        if (cmd.length() == 0) return new String[] { "" };
        
        StringBuilder arg = new StringBuilder();
        List<String> result = new ArrayList<String>();
        
        final char noQuote = '\0';
        char currentQuote = noQuote;
        for (int i = 0; i < cmd.length(); i++) {
            char c = cmd.charAt(i);
            if (c == currentQuote) {
                currentQuote = noQuote;
            } else if (c == '"' && currentQuote == noQuote) {
                currentQuote = '"';
            } else if (c == '\'' && currentQuote == noQuote) {
                currentQuote = '\'';
            } else if (c == '\\' && i + 1 < cmd.length()) {
                char next = cmd.charAt(i + 1);
                if ((currentQuote == noQuote && Character.isWhitespace(next))
                        || (currentQuote == '"' && next == '"')) {
                    arg.append(next);
                    i++;
                } else {
                    arg.append(c);
                }
            } else {
                if (Character.isWhitespace(c) && currentQuote == noQuote) {
                    if (arg.length() > 0) {
                        result.add(arg.toString());
                        arg = new StringBuilder();
                    } else {
                        // Discard
                    }
                } else {
                    arg.append(c);
                }
            }
        }
        // Catch last arg
        if (arg.length() > 0) {
            result.add(arg.toString());
        }
        return result.toArray(new String[0]);
    }
}