Nzip - a Comprehensive Command Line Utility
The Nzip command line utility implemented by the class de.schlichtherle.truezip.sample.file.app.Nzip showcases the power of the TrueZIP File* API.
This is a comprehensive command line utility which allows you to work with entries in any archive file supported by an archive driver (ZIP, TAR, TAR.GZ, TAR.BZ2 and relatives) using Unix like commands (cat, cp, mv, rm, mkdir, mkdirs, ls, ll , llr , touch etc). You can use this utility to conveniently copy entire directory trees into an archive file or from an archive file or any other virtual or non-virtual directory.
Setting The Stage
Before the examples are shown below, a little preparation is required in order to make it easier to start the utility class from the command line. With plain Java, you would have to start the utility class with a command like this:
$ java -jar truezip-7.7.10-jar-with-dependencies.jar %ARGS%
Where %ARGS% is a variable for arbitrary command line arguments - see below. This example uses TrueZIP's all-in-one JAR.
However, on Windows we would like to use something like this instead:
$ nzip.cmd %ARGS%
This can be done by copying the following script file with the name nzip.cmd in some directory on your %PATH%:
@echo off rem set PROPS=-Djava.awt.headless=true rem set PROPS=-Djava.util.logging.config.file=logging.properties set JAR=%USERPROFILE%\.m2\repository\de\schlichtherle\truezip\truezip-samples\7.7.10\truezip-samples-7.7.10-jar-with-dependencies.jar java %PROPS% -jar "%JAR%" %*
On Unix/Linux, this should be a bash script with the name nzip - I leave this as an exercise to you, however.
Examples
Following are some examples using the Nzip command line utility class. If you need help with the available commands and options, just run the Nzip command line utility class without parameters. It will print some help on standard error output then.
| Command | Description |
|---|---|
| nzip.cmd ll truezip-7.7.10-jar-with-dependencies.jar | Prints a detailed listing of the contents of the root directory of the JAR file from which the tool is actually running. |
| nzip.cmd llr truezip-7.7.10-jar-with-dependencies.jar | Prints a recursive long listing of the contents of the root directory of the JAR file from which the tool is actually running. |
| nzip.cmd cp truezip-7.7.10-jar-with-dependencies.jar/de/schlichtherle/truezip/sample/file/app/Nzip.class archive.zip/Nzip.class | Copies the file entry de/schlichtherle/truezip/sample/file/app/Nzip.class from the distribution JAR into the ZIP file archive.zip. |
| nzip.cmd rm archive.zip/de/schlichtherle/truezip/sample/file/app/Nzip.class | Removes the file entry Nzip.class from archive.zip/de/schlichtherle/truezip/sample/file/app. |
| nzip.cmd rmr archive.zip/de | Recursively removes the directory entry de from archive.zip. |
| nzip.cmd mkdir archive.zip/dir.zip | Creates the new ZIP file dir.zip in the existing ZIP file archive.zip. Remember that this API treats archive files like directories, so you can simply create a ZIP file by calling the mkdir() method on a File object. |
| nzip.cmd mkdirs archive.zip/a/b.zip/c/d.zip | Creates the new directory a containing the new ZIP file b.zip, containing the new directory c containing the new ZIP file d.zip within the existing archive.zip. |
| nzip.cmd rm archive.zip/a/b.zip/c/d.zip | Removes the empty ZIP file d.zip. Note that similar to regular directories, this succeeds on empty ZIP files only. |
| nzip.cmd touch archive.zip | Updates the last modification time of the existing ZIP file archive.zip to the current time. Note that if the given file does not exist, it is created as a plain file - you cannot create ZIP files using this method (use mkdir instead). |
| nzip.cmd mv archive.zip/Nzip.class . | Moves the entry Nzip.class from the ZIP file archive.zip to the current directory . . |
Note: Although TrueZIP has been designed to provide optimum performance, the Nzip utility is a feature showcase which cannot serve as a performance benchmark: The utility uses some optional archive drivers which are not normally used but provide extra safety and extra features at the price of performance, such as CRC-32 checking, scanning .exe files for self extracting ZIP files, etc. Furthermore, the start time of a JVM makes Java almost useless for short running command line utilities anyway.
Of course, you can substitute the .zip suffix in the examples above with any other canonical file type suffix recognized by the archive file drivers which are available on the run time class path (.ear, .jar, .war, .tar, .tgz, .tar.gz, .tb2, .tbz, .tar.bz2, .tzp, .zip.rae, .zip.raes).
For example, if you would like to use RAES encrypted ZIP files you would simply name the suffix .tzp in a path. So in order to copy the directory directory to an RAES encrypted ZIP file safe.tzp, you could run:
$ nzip.cmd cp directory safe.tzp
If you want to copy a plain file file instead, then run:
$ nzip.cmd cp file safe.tzp/file
New Options for ZIP Files
In TrueZIP 7.1 and 7.3, new options have been added to the cp command, primarily in order to support new options for ZIP files.
Use the following option in order to create a ZIP entry which is encrypted according to the WinZip AES encryption specification.
$ nzip.cmd cp -encrypt file true.zip/file
Use the following option in order to append a ZIP entry to the end of an existing ZIP file rather than reassembling the ZIP file. This might come in handy if the ZIP file is rather large compared to the single entry to add.
$ nzip.cmd cp -grow file true.zip/file
Sometimes you might want to use the STORED method rather than the DEFLATED method when writing an entry to a ZIP file. There's an option for this, too:
$ nzip.cmd cp -store file true.zip/file
For completeness, there's also an option to use the DEFLATED method. This is the default however, so you don't need to specify it:
$ nzip.cmd cp -compress file true.zip/file