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< meta name = "Author" content = "Norris Boyd" >
< meta name = "GENERATOR" content = "Mozilla/4.7 [en]C-NSCP (WinNT; U) [Netscape]" >
< title > JavaScript Shell< / title >
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< h1 >
JavaScript Shell< / h1 > < / center >
The JavaScript shell provides a simple way to run scripts in batch mode
or an interactive environment for exploratory programming.
< h2 >
Invoking the Shell< / h2 >
< tt > java org.mozilla.javascript.tools.shell.Main< / tt > [< i > options< / i > ]
< i > file< / i > < tt > .js
[< i > script-arguments< / i > ]< / tt >
< p > where < i > options< / i > are:
< p > < tt > -e < / tt > < i > script-source< / i >
< blockquote > Executes < i > script-source< / i > as a JavaScript script.< / blockquote >
< tt > -f < / tt > < i > script-filename< / i >
< blockquote > Reads filename specified by < i > script-filename< / i > and executes
it as a JavaScript script.< / blockquote >
< tt > -opt < / tt > < i > optLevel< / i >
< br > < tt > -O< / tt > < i > optLevel< / i >
< ul > Optimizes at level < i > optLevel< / i > , which must be an integer between
0 and 9. See < a href = "opt.html" > Optimization< / a > for more details.< / ul >
< tt > -version < / tt > < i > versionNumber< / i >
< ul > Specifies the language version to compile with. The string < i > versionNumber< / i >
must be one of < tt > 100< / tt > , < tt > 110< / tt > , < tt > 120< / tt > , < tt > 130< / tt > ,
or < tt > 140< / tt > . See < a href = "overview.html#versions" > JavaScript Language
Versions< / a > for more information on language versions.< / ul >
< h2 >
Predefined Properties< / h2 >
Scripts executing in the shell have access to some additional properties
of the top-level object.
< br >
< h4 >
arguments< / h4 >
< blockquote > The < tt > arguments< / tt > object is an array containing the strings
of all the arguments given at the command line when the shell was invoked.< / blockquote >
< h4 >
help()< / h4 >
< blockquote > Executing the help function will print usage and help messages.< / blockquote >
< h4 >
defineClass(< i > className< / i > )< / h4 >
< blockquote > Define an extension using the Java class named with the string
argument < i > className< / i > . Uses ScriptableObject.defineClass() to define
the extension.< / blockquote >
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< h4 >
deserialize(< i > filename< / i > )< / h4 >
< blockquote > Restore from the specified file an object previously written by a call to < tt > serialize< / tt > .< / blockquote >
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< h4 >
load([< i > filename< / i > , ...])< / h4 >
< blockquote > Load JavaScript source files named by string arguments. If
multiple arguments are given, each file is read in and executed in turn.< / blockquote >
< h4 >
loadClass(< i > className< / i > )< / h4 >
< blockquote > Load and execute the class named by the string argument < i > className< / i > .
The class must be a class that implements the Script interface, as will
any script compiled by < a href = "jsc.html" > jsc< / a > .< / blockquote >
< h4 >
print([< i > expr< / i > ...])< / h4 >
< blockquote > Evaluate and print expressions. Evaluates each expression,
converts the result to a string, and prints it.< / blockquote >
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< h4 >
runCommand(< i > commandName< / i > , [< i > arg< / i > , ...] [< i > options< / i > ])< / h4 >
< blockquote > Execute the specified command with the given argument and options
as a separate process and return the exit status of the process. For details, see JavaDoc for < a href = "http://lxr.mozilla.org/mozilla/source/js/rhino/toolsrc/org/mozilla/javascript/tools/shell/Global.java" > org.mozilla.javascript.tools.shell.Global#runCommand< / a > .< / blockquote >
< h4 >
serialize(< i > object< / i > , < i > filename< / i > )< / h4 >
< blockquote > Serialize the given object to the specified file.< / blockquote >
< h4 >
spawn(< i > functionOrScript< / i > )< / h4 >
< blockquote > Run the given function or script in a different thread.< / blockquote >
< h4 >
sync(< i > function< / i > )< / h4 >
< blockquote > creates a synchronized function (in the sense of a Java synchronized method) from an existing function. The new function synchronizes on the < code > this< / code > object of its invocation.< / blockquote >
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< h4 >
quit()< / h4 >
< blockquote > Quit shell. The shell will also quit in interactive mode if
an end-of-file character is typed at the prompt.< / blockquote >
< h4 >
version([< i > number< / i > ])< / h4 >
< blockquote > Get or set JavaScript version number. If no argument is supplied,
the current version number is returned. If an argument is supplied, it
is expected to be one of < tt > 100< / tt > , < tt > 110< / tt > , < tt > 120< / tt > , < tt > 130,< / tt >
or < tt > 140< / tt > to indicate JavaScript version 1.0, 1.1, 1.2, 1.3, or 1.4
respectively.< / blockquote >
< h2 >
Example< / h2 >
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< h4 > Invocation< / h4 >
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Here the shell is invoked three times from the command line. (The system
command prompt is shown as < tt > $< / tt > .) The first invocation executes a
script specified on the command line itself. The next invocation has no
arguments, so the shell goes into interactive mode, reading and evaluating
each line as it is typed in. Finally, the last invocation executes a script
from a file and accesses arguments to the script itself.
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< pre >
$ java org.mozilla.javascript.tools.shell.Main -e print('hi')
hi
$ java org.mozilla.javascript.tools.shell.Main
js> print('hi')
hi
js> 6*7
42
js> function f() {
return a;
}
js> var a = 34;
js> f()
34
js> quit()
$ cat echo.js
for (i in arguments) {
print(arguments[i])
}
$ java org.mozilla.javascript.tools.shell.Main echo.js foo bar
foo
bar
$
< / pre >
< h4 > spawn and sync< / h4 >
The following example creates 2 threads via < tt > spawn< / tt > and uses < tt > sync< / tt > to create a synchronized version of the function < tt > test< / tt > .
< pre >
js> function test(x) {
print("entry");
java.lang.Thread.sleep(x*1000);
print("exit");
}
js> var o = { f : sync(test) };
js> spawn(function() {o.f(5);});
Thread[Thread-0,5,main]
entry
js> spawn(function() {o.f(5);});
Thread[Thread-1,5,main]
js>
exit
entry
exit
< / pre >
< h4 > runCommand< / h4 >
Here is few examples of invoking < tt > runCommand< / tt > under Linux.
< pre >
js> runCommand('date')
Thu Jan 23 16:49:36 CET 2003
0
// Using input option to provide process input
js> runCommand("sort", {input: "c\na\nb"})
a
b
c
0
js> // Demo of output and err options
js> var opt={input: "c\na\nb", output: 'Sort Output:\n'}
js> runCommand("sort", opt)
0
js> print(opt.output)
Sort Output:
a
b
c
js> var opt={input: "c\na\nb", output: 'Sort Output:\n', err: ''}
js> runCommand("sort", "--bad-arg", opt)
2
js> print(opt.err)
/bin/sort: unrecognized option `--bad-arg'
Try `/bin/sort --help' for more information.
js> runCommand("bad_command", "--bad-arg", opt)
js: "< stdin > ", line 18: uncaught JavaScript exception: java.io.IOException: bad_command: not found
js> // Passing explicit environment to the system shell
js> runCommand("sh", "-c", "echo $env1 $env2", { env: {env1: 100, env2: 200}})
100 200
0
js> // Use args option to provide additional command arguments
js> var arg_array = [1, 2, 3, 4];
js> runCommand("echo", { args: arg_array})
1 2 3 4
0
< / pre >
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