- Zip Expert 1 0 – Extract Create Archive Files Smaller
- Zip Expert 1 0 – Extract Create Archive Files File
- Zip Expert 1 0 – Extract Create Archive Files Free
Archive::Zip::FAQ - Answers to a few frequently asked questions about Archive::Zip
(Required) Specify the compression scheme used. To create foo.jar, for example, choose zip for the compression, and specify foo.jar as the archive file to create. For all tar files (including compressed ones), choose tar. Zip - default, zip format, choose this for all zip compatible types, (.zip,.jar,.war,.ear) 7z - 7-Zip format, (.7z). Description of 7-Zip archive packer and extractor. Open, browse, view and extract ZIP archive files. Encrypt files with password. Create self-extract archives.; Unpack and decrypt 128-bit and 256-bit key AES-encrypted files (Rijndael cryptographic algorithm, Advanced Encryption Standard). To create a ZIP file as before and also include the archive sub-directory, use this command. Zip -r -q sourcecode archive/.c.h. To be considerate to the person who will be extracting the files from the ZIP file you're creating, it is often polite to create ZIP files with the files inside it contained in a directory. Recover Data for Zip archive repair software has been developed by Recover Data expert engineers with advanced file repair & data recovery algorithm to restore data from damaged zip files & get zip data back to its original state. Winzip recovery software makes a quick or deep scan of all the selected zip files for saving user precious time.
It seems that I keep answering the same questions over and over again. I assume that this is because my documentation is deficient, rather than that people don't read the documentation.
So this FAQ is an attempt to cut down on the number of personal answers I have to give. At least I can now say 'You did read the FAQ, right?'.
The questions are not in any particular order. The answers assume the current version of Archive::Zip; some of the answers depend on newly added/fixed functionality.
Q: Archive::Zip won't install on my RedHat 9 system! It's broke!
A: This has become something of a FAQ. Basically, RedHat broke some versions of Perl by setting LANG to UTF8. They apparently have a fixed version out as an update.
You might try running CPAN or creating your Makefile after exporting the LANG environment variable as
LANG=C
Q: My zip file is actually bigger than what I stored in it! Why?
A: Some things to make sure of:
$member->desiredCompressionMethod( COMPRESSION_DEFLATED );
Since zip computes the compression tables for each member, small members without much entropy won't compress well. Instead, if you've got lots of repeated strings in your data, try to combine them into one big member.
Zip Expert 1 0 – Extract Create Archive Files Smaller
If you're storing a .zip, .jpg, .mp3, or other compressed file in a zip, then don't compress them again. They'll get bigger.
Q: Can you send me code to do (whatever)?
A: Have you looked in the examples/ directory yet? It contains:
- examples/calcSizes.pl -- How to find out how big a Zip file will be before writing it
- examples/copy.pl -- Copies one Zip file to another
- examples/extract.pl -- extract file(s) from a Zip
- examples/mailZip.pl -- make and mail a zip file
- examples/mfh.pl -- demo for use of MockFileHandle
- examples/readScalar.pl -- shows how to use IO::Scalar as the source of a Zip read
- examples/selfex.pl -- a brief example of a self-extracting Zip
- examples/unzipAll.pl -- uses Archive::Zip::Tree to unzip an entire Zip
- examples/updateZip.pl -- shows how to read/modify/write a Zip
- examples/updateTree.pl -- shows how to update a Zip in place
- examples/writeScalar.pl -- shows how to use IO::Scalar as the destination of a Zip write
- examples/writeScalar2.pl -- shows how to use IO::String as the destination of a Zip write
- examples/zip.pl -- Constructs a Zip file
- examples/zipcheck.pl -- One way to check a Zip file for validity
- examples/zipinfo.pl -- Prints out information about a Zip archive file
- examples/zipGrep.pl -- Searches for text in Zip files
- examples/ziptest.pl -- Lists a Zip file and checks member CRCs
- examples/ziprecent.pl -- Puts recent files into a zipfile
- examples/ziptest.pl -- Another way to check a Zip file for validity
Q: Why can't I open a Zip file, add a member, and write it back? I get an error message when I try.
A: Because Archive::Zip doesn't (and can't, generally) read file contents into memory, the original Zip file is required to stay around until the writing of the new file is completed.
The best way to do this is to write the Zip to a temporary file and then rename the temporary file to have the old name (possibly after deleting the old one).
Archive::Zip v1.02 added the archive methods overwrite() and overwriteAs() to do this simply and carefully.
See examples/updateZip.pl for an example of this technique.
Q: Upon extracting files, I see that their modification (and access) times are set to the time in the Zip archive. However, their creation time is not set to the same time. Why?
A: Mostly because Perl doesn't give cross-platform access to creation time. Indeed, many systems (like Unix) don't support such a concept. However, if yours does, you can easily set it. Get the modification time from the member using lastModTime().
Q: Can I use Archive::Zip to extract Unix gzip files?
A: No.
There is a distinction between Unix gzip files, and Zip archives that also can use the gzip compression.
Depending on the format of the gzip file, you can use Compress::Raw::Zlib, or Archive::Tar to decompress it (and de-archive it in the case of Tar files).
You can unzip PKZIP/WinZip/etc/ archives using Archive::Zip (that's what it's for) as long as any compressed members are compressed using Deflate compression.
Q: How can I add a directory (or tree) full of files to a Zip?
A: You can use the Archive::Zip::addTree*() methods:
Zip Expert 1 0 – Extract Create Archive Files File
Q: How can I extract some (or all) files from a Zip into a different directory?
A: You can use the Archive::Zip::extractTree() method: ??? ||
Q: How can I update a Zip from a directory tree, adding or replacing only the newer files?
A: You can use the Archive::Zip::updateTree() method that was added in version 1.09.
Q: It bothers me greatly that my file times are wrong by one second about half the time. Why don't you do something about it?
A: Get over it. This is a result of the Zip format storing times in DOS format, which has a resolution of only two seconds.
Q: My file times don't respect time zones. What gives?
A: If this is important to you, please submit patches to read the various Extra Fields that encode times with time zones. I'm just using the DOS Date/Time, which doesn't have a time zone.
Q: I want to make a self-extracting Zip file. Can I do this?
A: Yes. You can write a self-extracting archive stub (that is, a version of unzip) to the output filehandle that you pass to writeToFileHandle(). See examples/selfex.pl for how to write a self-extracting archive.
However, you should understand that this will only work on one kind of platform (the one for which the stub was compiled). Gopanel 1 9 4 – manage web servers unavailable.
Q: How can I tell if a Zip has been damaged by adding garbage to the beginning or inside the file?
A: I added code for this for the Amavis virus scanner. You can query archives for their 'eocdOffset' property, which should be 0:
When members are extracted, this offset will be used to adjust the start of the member if necessary.
Q: I'm trying to extract a file out of a Zip produced by PKZIP, and keep getting this error message:
A: You can't uncompress this archive member. Archive::Zip only supports uncompressed members, and compressed members that are compressed using the compression supported by Compress::Raw::Zlib. That means only Deflated and Stored members.
Your file is compressed using the Shrink format, which is not supported by Compress::Raw::Zlib.
You could, perhaps, use a command-line UnZip program (like the Info-Zip one) to extract this.
Q: How do I decrypt encrypted Zip members?
A: With some other program or library. Archive::Zip doesn't support decryption, and probably never will (unless you Protectworks antivirus 2 0 6. write it).
Q: How can Archive::Zip can test the validity of a Zip file?
A: If you try to decompress the file, the gzip streams will report errors if you have garbage. Most of the time.
Appdelete 4 2 4. If you try to open the file and a central directory structure can't be found, an error will be reported.
When a file is being read, if we can't find a proper PK. signature in the right places we report a format error.
If there is added garbage at the beginning of a Zip file (as inserted by some viruses), you can find out about it, but Archive::Zip will ignore it, and you can still use the archive. When it gets written back out the added stuff will be gone.
There are two ready-to-use utilities in the examples directory that can be used to test file integrity, or that you can use as examples for your own code:
- examples/zipcheck.pl shows how to use an attempted extraction to test a file.
- examples/ziptest.pl shows how to test CRCs in a file.
Q: Archive::Zip let me put the same file in my Zip twice! Why don't you prevent this?
A: As far as I can tell, this is not disallowed by the Zip spec. If you think it's a bad idea, check for it yourself:
I can even imagine cases where this might be useful (for instance, multiple versions of files).
Q: Why doesn't Archive::Zip deal with file ownership, ACLs, etc.?
A: There is no standard way to represent these in the Zip file format. If you want to send me code to properly handle the various extra fields that have been used to represent these through the years, I'll look at it.
Q: I've only installed modules using ActiveState's PPM program and repository. But they have a much older version of Archive::Zip than is in CPAN. Will you send me a newer PPM?
A: Probably not, unless I get lots of extra time. But there's no reason you can't install the version from CPAN. Archive::Zip is pure Perl, so all you need is NMAKE, which you can get for free from Microsoft (see the FAQ in the ActiveState documentation for details on how to install CPAN modules).
Q: How come my JPEGs and MP3's don't compress much when I put them into Zips?
A: Because they're already compressed.
Q: I'm using Windows. When I try to use Archive::Zip, my machine locks up/makes funny sounds/displays a BSOD/corrupts data. How can I fix this?
A: First, try the newest version of Compress::Raw::Zlib. I know of Windows-related problems prior to v1.14 of that library.
Zip Expert 1 0 – Extract Create Archive Files Free
Q: I want to read a Zip file from (or write one to) a scalar variable instead of a file. How can I do this?
A: Use IO::String and the readFromFileHandle() and writeToFileHandle() methods. See examples/readScalar.pl and examples/writeScalar.pl.
Q: How do I read from a stream (like for the Info-Zip funzip program)?
A: This is not currently supported, though writing to a stream is.
To install Archive::Zip::FAQ, copy and paste the appropriate command in to your terminal.
For more information on module installation, please visit the detailed CPAN module installation guide.
Many people struggle when faced with a zip file and don't understand what to do with it. I'll try to explain and look at options for different devices.
Why use zip and what is it?
When you want to download large or small files to your Windows or Mac PC or tablet computer, the standard format is a compressed file such as zip. There are other compressed file formats such as rar, gzip, 7-zip and many others, but they are all effectively a ‘container' for the files that you ultimately want to download.
We use zip to reduce the overall file size and make the transfer over the internet much quicker. The files can then be extracted from their container (the zip file) by ‘unzipping'. This is also known as extracting or decompressing. To do this, we use a utility program such as 7Zip. There is also built-in unzipping in Windows XP, Vista, Windows 7 and Windows 8, although it is not as competent as the 7zip program. 7zip is completely free, it's stable and reliable and it can be installed on any Windows computer. Download it here:
https://www.7-zip.org/ (opens in a new window for you).
Make sure you get the correct version for your computer, there are 2 versions – 32 and 64 bit. If in doubt, get the 32 bit.
Using 7Zip to compress and extract files
Look at this video that explains both in detail:
How do I unpack zipped or compressed files on my Android device?
The Android operating system does not come with an unzipping program but you can download them from Google Play. Look at WinZip, AndroZip File Manager or WinRAR. As usual, note that some applications on Google Play are free but many carry advertising or a hidden price.
To download and install them, visit Play Store from your Android device's home screen. Check user reviews if you are unsure which to go for.
Personally, I like to unzip the files on my desktop PC and send them to the tablet using a file sharing and syncing utility such as Dropbox (free) or the excellent Livedrive (Free trial). This type of seamless file sharing is such an aid to moving files around devices you own and also backs up these files in ‘the cloud'.
Using WinZip to create a zip archive
WinZip is proprietary software that has an evaluation period. This allows you to use the program for free for a limited time, after which you should purchase a licence.
For Windows 7, Windows 8 or Vista
Tip – hold down Ctrl and left click to select multiple files at once.
- Open WinZip and select Add files
- Choose the first file you want to add and click Zip
- Choose a name and where to save your zip archive then click Create
- Click Add files to choose another file Zip to add it to the archive
- Repeat until all of your files have been added
For Windows XP
- Open WinZip and select New
- Choose a name and where to save your zip archive then click Ok
- Choose the first file you want to add and click Add
- To add more files, click the Add button in WinZip and choose another file
Using 7-Zip to create an archive
7-Zip is free software that allows you to create and view many types of archive formats including zip.
Tip – hold down Ctrl and click to select multiple files at once.
- Select the files on your computer
- Right click on the highlighted files and choose 7-Zip then Add to archive
- Under Archive choose a name for your file and where you want to save it
- Change the archive format to zip, everything else can be left as the default values
- Click Ok
Hope this helps you to understand and use zip files.
