Compression decreases the size of data.

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201 views

Untar multiple files at once?

I'm on Windows 7 and have a number of .tar files with the following names: .tar-aa .tar-bb .tar-cc ... The tar files contain a large backup directory which is broken up into chunks of 250MBs each. ...
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2answers
154 views

Compress a remote folder in Linux

I'm a Linux newbie and I'm trying to zip a folder which exists on a remote host and export it to another remote host. A quick Google search lead me to tar/gzip and rsync options but I'm not sure how ...
0
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2answers
301 views

Good way to reduce number of colors in a PDF file?

I have pages of handwritten notes that I decided to scan to a PDF. Somehow, 153 pages of notes turned into a 156.4 MB PDF file. The notes are scanned in color because I used four different colors: ...
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1answer
447 views

Is it possible to recursively list zip file contents with 7 zip without extracting

Similar to this question I have a very large zip file which contains other zip files, folders, and files. I want to use 7-zip to extract a list of file names from it, recursing into subfolders and zip ...
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2answers
221 views

Is there a client impact to server side NTFS compression?

One of a our file servers at work is being compressed with NTFS compression. I've read about it being generally inadvisable on servers. But I've not found anything the states where the ...
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3answers
922 views

powershell create zip from log files

How can I move log files to zip archives with System.IO.Compression.FileSystem in PowerShell? I have more folders with log files per application: app1logfolder |-app1_20130507.log ...
0
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1answer
63 views

mod_deflate - possible to compress 1k or higher only? cache?

Is there a way to tell mod_deflate in .htaccess to only compress files if they are at least 1kb? Also, can it cache compression results? Once it compresses a file, I want it to use that again instead ...
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2answers
272 views

When compressing a file on command prompt with RAR command, how to stop the process without cancelling it?

I used the following command: rar a -m2 file.rar *.xml \\myroute\ I want to stop the process on the file that have already been processed i.e. using Ctrl + C will cancel the process but not finish ...
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0answers
166 views

Difference between lzip, 7z and zipx [closed]

I would like to know what is the difference between the algorithms used in these three compression schemes. I found that all three of them are based on LZMA. But I would like to know what makes them ...
0
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1answer
1k views

Can't view files from within WinRar (Win7 x64)

I have an issue with WinRar (64 bit version) on Windows 7 (x64) that is similar to the one described in another open question on this website Link to the same issue on this site (unanswered) However, ...
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2answers
555 views

What is the difference in various commands for compressing files in linux?

What are the commands for compressing files in linux and what are the difference between them? (for example: tar, gzip, rar). I'm working on Linux Mint 11 and doing a script for compressing files. I ...
0
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1answer
939 views

What compression algorithms are used by rar? [closed]

I am reading about many compression and archiving techniques.. I am not able to find the compression algorithms that are used by rar. Also I would like to know if rar compresses each file separately ...
0
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1answer
919 views

How do I compress a 200MB MOD video file?

My grandpa sends me this huge 200MB video file and asks me to compress it. I bet that there are many ways I can do this. For instance, just guessing some ideas: Use an online conversion tool ...
2
votes
2answers
225 views

Does OS X Preview support saving PDF with JBIG2 compression?

I have a PDF file containing hundreds of BW scannings, that I created on Windows using lossy JBIG2 compression, resulting in a nice 8MB file. I can open that file on OSX with Preview, but if I add ...
1
vote
1answer
232 views

Copying all the files of one extension into a folder

I have been trying to write a .bat program which will find all the files with a given extension, for example *.doc, and will put them into a rar archive. I want all the files to be copied even if ...
1
vote
1answer
331 views

Can we save and resume winrar jobs?

I'm trying to zip a 87 GB folder into multiple volumes, 1 GB each. WinRar is able to do that, however the entire job takes about 20 hours. Is there anyway to save and resume the state of the WinRar ...
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0answers
2k views

“extra bytes at beginning or within zipfile,” won't open file

I have an 8.3 gig zip containing tons of telescope observation data, but I can't extract no matter what I try. I've tried Archive Manager, unzip, and tried this guy's fix: ...
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3answers
3k views

Between xz, gzip, and bzip2, which compression algorithim is the most efficient?

Between xz, gzip, and bzip2, which compression algorithm gives the smallest file size and fastest speed when compressing fairly large tarballs?
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votes
1answer
2k views

Does OS X support disk compression?

I am new to the Mac world. As you may know, NTFS has options to "Compress this drive to save disk space" or "Compress contents to save disk space". I want to know whether OS X supports this feature ...
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2answers
2k views

gzip several files in different directories and copy to new directory

I'm working with several files that are located in different directories that I need to compress into individual .gz files. I also need to move the compressed files to a single directory while leaving ...
1
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3answers
546 views

What is the equivalent unix command to a Mac OSX “Compress” menu action?

When I right-click a file in Mac OSX and select "Compress 'File Name'", what is the equivalent bash or terminal command to get the same result? Is it just gzip -9 /path/to/filename?
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votes
5answers
16k views

What if I checked the box “Compress this drive to save disk space” on an SSD?

I was wondering how it would effect an SSD if this was checked: I was just curious whether it would save my SSD disk space?
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2answers
256 views

Compress Similar Files Efficiently

I frequently have the need to compress files that are very similar to each other. Currently I use 7Zip, which compresses a 16GB file down to 1.2GB in about 35 minutes using 8 cores with Ultra ...
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1answer
1k views

Split a folder of files into multiple zip files based on size or # of files

My problem is that the file uploader I'm working with will only allow a zip file with a size of 10mb or less. Unfortunately, I have thousands of files that need to be processed and I do this by ...
2
votes
1answer
649 views

Why is ZFS gzip-9 compression so much worse than actually using zip files?

I am working with some very large packet capture files (~150GB across 30 files) but because of how highly redundant packet captures are, these compress to ~7% (14.29x) of their originally file size ...
2
votes
2answers
255 views

Compress an attachment in my mailclient inside my INBOX?

I got a lot of emails with uncompressed formats (like bmp, txt, ...) that I want to keep inside my IMAP-inbox, so I can access them from all my devices (Windows, Linux, ios, Android). Those emails ...
2
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2answers
3k views

How to zip multiple folders in 7zip?

I have a folder, lets say, MAIN. Inside this folder, there are many folders(say f1,f2,f2...) which has subfolders and files in them. Now I need to zip these folders(f1,f2,f3...) and their contents ...
4
votes
2answers
810 views

Create a .png with zopfli

I wanted to give zopfli a try since I have some static .png's that I am using on a website. I see how I can create .gz and .deflate-files. But how can I create a png that can be displayed in FF, ...
2
votes
2answers
364 views

Deduplicate Files inside multiple .tar.gz archives

I take a nightly backup from my Webhosting service as .tar.gz. The Data changed is very little each night (<10MB). I would like to archive these files and deduplicate (solid compression) files ...
2
votes
1answer
3k views

Shell Script to GZIP files without overwrite .gz files

I'm trying to create a shell script which receive as first parameter of a path to a folder which I would like to compress all files using gzip without overwrite the .gz files that already exist in ...
2
votes
1answer
325 views

How would Apache or Compressed HTTP react to a zip bomb?

inspired by Compress a 1GB file into 200_MB? and the related comments: Many webservers today use a zipped HTTP Version (Gzip afaik). How would Apache or any other server react to a zip bomb? Since ...
2
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4answers
12k views

Compress a 1GB file into 200_MB?

So I just downloaded MySQL for Windows 64bit which 211.9MB but when I extracted it it is now 1.05GB. How did they do it? They archive wasn't damaged at all nor corrupted. Before (Compressed): ...
0
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1answer
496 views

Windows 7 extract and compress zip has been compromised by NCH's Express Zip program. How to fix?

I installed NCH's Express Zip, and now I can no longer use Windows 7's way of extracting and compressing. I would like to get rid of the NCH program and get back the original functionality of windows ...
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2answers
163 views

Are there any libraries that determine if a file is worth compressing before being transferred?

I've read that sometimes files like .mp3's or compressed images aren't worth compressing (with zlib for example) because they are already compressed and they'd waste more CPU resources than save ...
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0answers
1k views

How to verify 7zip'd files integrity

For some files I have compressed, I have been looking for a MD5 add-on to 7zip (As I have the MD5's by way of an Explorer Column Handler, in xplorer2); or a CRC Explorer Column Handler (Because 7Zip ...
1
vote
1answer
2k views

How do I compress multiple files into one archive using lzma?

Looking at the options of xz and lzma, I can't for the life of me figure out how to compress multiple files into one archive. I know it is possible because I've uncompressed a .lzma file and it opened ...
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0answers
63 views

7zip - How to overwrite a existing file? [duplicate]

Possible Duplicate: How can I overwrite an existing file in 7zip? I'm trying this: 7za.exe a "C:\Disc.7z" "C:\test" -v20000000b -m0=BCJ -bd But if I already have created the file ...
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5answers
5k views

How can I overwrite an existing file in 7zip?

I'm trying this: 7za.exe a "C:\Disc.7z" "C:\test" -v20000000b -m0=BCJ -bd But if I already have created the file C:\Disc.7z then 7zip doesn't compress anything and sends me this output: System ...
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0answers
75 views

LZMA Based Archiving on Linux

I am trying to build an archiving system. I have tested out LZMA compression algorithm, and it provides very good results. However, I need the ability to add and retrieve(will remain in the archive) ...
0
votes
1answer
2k views

Unpack NSIS executable

I am trying to decompress a NSIS executable. With the GUI version of 7zip I am able to do this and the exe is listed as: Type = Nsis Method = LZMA:25 Solid = + With the command line version 7za I ...
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2answers
2k views

Synchronizing files using 7zip and the CLI

In the command line, 7zip has the command 'a' to "Add files to archive". But I want to sync the files instead. This is one of the main options in the GUI, but the CLI has disregarded it for some ...
0
votes
1answer
210 views

Poor compression of compact flash image, even after 0 fill

Problem: I am attempting to create an exact image of a compact flash and then compress the compact flash image for easier storage. The compact flash is not full (~1.5GB used, 32GB size). The problem ...
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vote
2answers
344 views

Compressing multiple files into multiple archives?

I have a folder full of pdfs and I'm tired of Winraring each file separately. I don't want to put them all in one archive. Isn't there a command line I can use to make Winrar compress a file with ...
-1
votes
1answer
109 views

How to achieve the compression level of a PDF scanner

I have one paper scanned into a PDF, which has a size of about 700KB and 300dpi. But if I take a snapshot of the PDF file using DPI settings of 300 as well, the image file (in PNG, JPG, or TIFF) is ...
0
votes
1answer
286 views

I am trying to zip files individually, but the file type is unknown

I am trying to zip some files with an unknown file type individually. I am using the following code in a batch script to do that: @ECHO OFF FOR %%A IN (bestbuy*nat*component.cpi*) DO "C:\Program ...
2
votes
1answer
67 views

Find out who compressed the files

I received a message that contains a compressed RAR file. How can find out who compressed the files and created RAR file? (the user account or computer name)
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1answer
74 views

Is there any file compression program that supports saving session and resuming when files become inaccessible?

I intend to make one-time backup of ca. 100GB files from NAS. Unfortunately, due to poor design, the backup machine is limited to wireless access with the NAS. I expect the connection to break ...
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0answers
45 views

Archive / compression formats or tools which support multiple file forks or streams?

Lately I've become interested in the ability of several filesystems including Apple's HFS+ and Microsoft's NTFS which support two or more data streams. In Mac terminology these were most widely ...
9
votes
4answers
16k views

How to obtain maximum compression with .tar.gz? [duplicate]

The way i understand the use of tar + gzip is that tar is normally used to consolidate a grouping of files into a single file, then gzip is used to compress that file. I recently learned that tar can ...
6
votes
3answers
8k views

How do I reduce the file size of videos?

I need to reduce the file size of some of my HD videos, since I am running out of storage space. A lower resolution is acceptable, and other methods are welcome. I would prefer a GUI solution, as I am ...