Compression decreases the size of data.

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Merging many .rar files in one .rar file

I have about 200GB of rar part files (all .rar) that I would like to merge into 1 single .rar file. I'm trying to perform this in Windows. How would one go about merging many a rar file without ...
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1answer
179 views

Force all files in a NTFS compressed folder to automatically compress [Windows]

Is it possible to keep all the files within a NTFS-compressed folder compressed? For example, if I have a compressed a folder using NTFS compression, it will compress all the files inside the folder ...
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4answers
2k views

Can Double Zipping Cause Problems?

I have a directory that I have been storing a ton of files in. Among the 10ish types of files there are also .zips of other directories. In my personal experience I vaguely remember issues when ...
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5answers
2k views

Why is a 7zipped file larger than the raw file? [duplicate]

Possible Duplicate: Why doesn't ZIP Compression compress anything? I tried 7zipping an .exe file but it actually became larger. Is this the expected result?
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1answer
19 views

Compress / Zip a folder periodically but use minimal CPU?

Similar to this question except, I need it to run with minimal CPU on the background? Also, if there's a 7zip solution that will be nice.
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2answers
11k views

Is zip's encryption really bad? [closed]

The standard advice for many years regarding compression and encryption has been that the encryption strength of zip is bad. Is this really the case in this day and age? I read this article about ...
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0answers
30 views

Compressed file with a header containing all files within it, at the beginning of the file

I have noticed that most files resulting from a compression / archive process do not have a list of the files contained at the beginning of the resulting file, but rather at the end of it. For ...
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0answers
27 views

Store disc images on a hard drive

I'm cleaning up around my computer (A Win7 ultimate machine), and part of my plan is to rip all my program CDs and store them on a dedicated 1TB hard drive. My initial plan was to simply dump the ...
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4answers
77k views

How to decompress a .bz2 file

I have a file as: filename.bz2, but I can't figure out how to decompress it. I tried several methods, none of them seems work. I have tried the command: tar xvjf filename.tar.bz2, but it didn't work ...
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0answers
170 views

How to unpack a compressed executable without knowing the compression algorithm

I'm not sure if this question was asked. I searched for it and could not find it. How can I unpack a compressed executable without knowing what compression algorithm was used to compress it? For ...
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1answer
1k 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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4answers
8k views

How to obtain maximum compression with .tar.gz?

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 ...
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2answers
1k views

zip: Argument list too long (80.000 files in overall)

I need to compress 80.000 files into multiple zip files. This is the command I use: zip -s 200M photos_test/* However I get the following error: -bash: /usr/bin/zip: Argument list too long What ...
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0answers
11 views

Improve seeking precision for wma encoded in ffmpeg

Compressed audio formats (like compressed video) have trouble doing precise seeking. Is there something in the ffmpeg encode settings that I can change to make the resulting audio file allow more ...
3
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1answer
1k views

tar/bz2 compress a file removing uncompressed original

Is there any way to turn a directory called dir1 into dir1.tar.bz2 without keeping the original? I need to save space and want to compress some large files but don't have enough room to keep a ...
3
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1answer
33 views

Is there any solution/utilities to compress and upload a large file simultenously?

Upload a large file via broadband connection takes time. Compress the file using max. compression ratio before upload also consume time. Is there any solution that may compress and upload file to ...
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1answer
84 views

When putting two identical files in a .zip, they take 2x space, can this be avoided

Say that you have a file you want to put in a .zip archive: zip a1.zip foo.dll My test .dll file is ~10MB, and the archive turns out to be 3.5MB Then you create a file with the exact same ...
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0answers
9 views

Compressing with BarCat?

I'm having an issue using Barcat to show a dialog while compressing? Wondering what the exact syntax is? here's a link to Barcat things I've tried are bar -n apache24.tar.xz |tar -Jcf - bar -n ...
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2answers
107 views

How can I search for files that are either compressed or uncompressed in Windows Explorer?

I know that Windows explorer can colorize the NTFS compression state of a file, in both the regular and search views. How can I specifically filter/search for files that are compressed or ...
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0answers
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Compress whole internet session on all apps [duplicate]

As my main internet connection, I am currently using the USB tethering feature of my Android phone. My question is this: Can I compress my whole internet session in all apps (not only in Opera using ...
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0answers
41 views

Compress 1 TB file collection into standalone archives each size no more than 2GB

I have about 1TB data stored in two drives and I need to compress and encrypt them into independent archives each size must be smaller than 2GB. Exception may be files that are larger than 2GB. Is ...
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2answers
50 views

How can I achieve the maximum zip compression? [closed]

I would like to make a "standard" zip file which contain .jpg images. Which software and switches / options should I use to achieve the maximum compression ratio? I mean maybe I can make a solid ...
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0answers
33 views

Improve slow NAS Ethernet transfer speeds: On-The-Fly Ethernet Compression with SAMBA?

Hardware: Pogoplug E02 (ARMv5te, Marvell Kirkwood 1.2GHz, 256m RAM) Software: ArchLinux, MDADM RAID 5 array, Ext4, SAMBA server This setup delivers file transfers to my Windows clients at ~21MB/s ...
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2answers
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NTFS compressed folders: is it possible to tweak compression ratio?

As it seems, Windows compresses the NTFS compressed folders with the lowest compression ratio possible. While this maybe good for increasing speed and decreasing CPU load, for the files that are ...
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4answers
14k views

How to highly compress files

I want to learn how to highly compress a file. I have downloaded files whose compressed size was 4 GB, and after extracting they became 10 GB. Which software do I need to use for such high ...
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5answers
3k views

Whatever happened to compressed read/write filesystems?

Back in the 90s, my home computer was an Acorn Archimedes. It had on it a piece of software called ArcFS, which allowed you to create compressed archives, a bit like zip files. Unlike zip files, they ...
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229 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 ...
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4answers
16k views

Can I compress a RAR file again to reduce its size?

I had a 326 MB iso file that I compressed using WinRAR, with the best compression method. It got compressed to 144 MB. I want to compress more and want it to be limited to something around 22 MB. ...
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2answers
5k views

Untar a given linux tarball on MAC OS X

I have a Linux tarball that can't be unpacked. It gives me an unexpected error. I am told this is due to case insensitive on MAC OS X. How can I untar this file? tar -zxvf file.tar.gz ... x ...
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1answer
22 views

How do I back up images with limited disk space?

I'm in a scenario where I have one 500GB hard drive and about 400GB of images I want to tar. I obviously won't have enough disk space, but I don't mind getting rid of the images as they are added to ...
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0answers
30 views

Tape backup with compression

I would like to backup a NAS to a series of LT02 tapes, (200 gigs uncompressed, 400gigs compressed.) There are about 700 gigs of data to back up. I initially tried cpio, first trying to set hardware ...
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1answer
47 views

What is the difference between rar and RAR5 compression?

What is the difference between rar and RAR5 compression ? Which is better for which purpose vs the compression time.
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1answer
45 views

Recursively process zip archives to extract files while discarding specific format of files

On my Windows 7 machine, I have a directory full of downloaded dumps in ZIP archives. Each archive contains few text files, PDFs and rarely XML files. I want to extract all the contents of each ZIP ...
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4answers
4k views

How do I know the gzip compression level?

Given a gzip compressed file, how do I know what compression level (1-9) was used for it?
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0answers
12 views

How to have zpaq extract files to stdout

I have some log files compressed with ZPAQ that I do not want to extract to disk every time I need to go grep-ing for events. Would like to extact to stdout so I can handle the output the same way as ...
0
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2answers
30 views

I cannot open folders in .tar file

I've downloaded factory image for my Nexus4 mobile, the Image folder is compressed in .tar file but it tells me that its unknown file Type: File ,, how can i open it? here take some photo of my ...
2
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2answers
958 views

Creating .xz with 7-Zip, claims insufficient memory (not true)

In WinXP 32bit with a Core i5 (dual core) and 4GB RAM, I'm trying to create an .xz archive from a 266MB log file using 7-Zip (GUI) on the "ultra" compression level (method: LZMA2, dictionary size: ...
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3answers
43 views

Zero sized tar.gz file found inside a tar.gz file

My current directory contains a single file like this- $ls -l -rw-r--r-- 1 root staff 8 May 28 09:10 pavan Now, I want to tar and gzip this file like $tar -cvf - * ...
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1answer
23 views

How can I compress a series of integers?

BARF2 (Better Archiver with Recursive Functionality) generates a huge barf2.count file, which is a number-only file. What's the best way to compress that?
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2answers
224 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 ...
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0answers
23 views

Cannot complete the compressed folder extraction wizard

Recently my friend archived a folder in linux (Redhat) and uploaded in Google Drive. I have downloaded the .zip file and trying in it to unzip in windows 7. I am receiving following error: Cannot ...
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0answers
24 views

Why would my zipped file be the same size as the uncompressed files? [duplicate]

I am trying to zip 13 mp4s. The uncompressed versions of those files are 2.69GB. But when I zip them with 7zip, using Ultra compression level and any of the compression methods - including LZMA, the ...
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0answers
18 views

image drive with safecopy and compress the output

I am trying to image a drive with SafeCopy and compress the output file on the fly so that it won't take up way too much space. (aka 500GB > 50GB) Will this command work? sudo safecopy --stage1 ...
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3answers
100 views

How big is an 800x600 image file in PNG? [closed]

How big is an 800x600 image file supposed to be in PNG ? Actually what I would really like is a table that shows resolutions on the y-axis and formats/compression type on the x-axis. I ask this ...
2
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4answers
7k 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
35 views

Should I extract before running?

Is it not wise to run an executable from a zipped file without extracting first? Someone explained to me that there is no need to extract first. He explained that zipped files are nothing more than ...
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1answer
105 views

How to compress 14 GB of csv files with 7zip (minimizing space)?

I have to compress 14 GB of csv files with 7zip. What options should I use to achieve the highest compression? I have tried Ultra Level with both LZMA and PPMd compression method, obtaining results ...
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0answers
38 views

Fast way to forward an Outlook email as a zip

I need to find a quick way to select an email in Outlook 2010 and forward the email as a zip attachment. The recipient will always be the same. The subject and body of the email will always be the ...
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0answers
99 views

Difference between downscaling 1080p to 720p in real time and downscaling during encoding?

Suppose a high quality, uncompressed video is re-encoded twice, with almost identical encoding settings at a relatively low bitrate of 4mbps, but at different resolutions, first at 1080p, and then at ...
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Webm video flashes compression artefacts

Doing som testing on capturing video from VirtualBox for a screencasting project. VirtualBox uses webm for video and it works sort of OK. However, it has "flashes" of heavy compression artefacts. ...