1
vote
1answer
57 views

7-Zip: Unsupported Compression Method while trying to extract a zipx file that consists of JPEGs

A zipx file I received consists of .csv files and .jpeg files. I used 7-zip to extract them. While the .csv files were sucessfully extracted, the JPEG files didn't. The error was something like this ...
6
votes
2answers
138 views

What does combining compression methods in 7z actually do?

The 7z command-line tool lets you specify multiple compression methods, e.g.: # 7-zip archive type, strongest (9) compression, methods PPMd, BCJ2, LZMA2 $ 7z a -t7z -mx=9 -m0=PPMd -m1=BCJ2 -m2=LZMA2 ...
-1
votes
1answer
46 views

What 7zip settings to compress very large partition image?

I have 77 GB big partition backup image in single file and I'd like to compress it quickly. It should compress very well even on worst settings, but choosing GZIP with "Fastest" setting takes about ~1 ...
1
vote
1answer
31 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.
0
votes
2answers
73 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 ...
0
votes
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 ...
0
votes
1answer
199 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 ...
0
votes
0answers
33 views

Sequential Compression of [Text] Files (7zip and Windows)

This is with Windows 7. I have an iterative process, and on each iteration it produces a text file. What I want to do is compress this text file on each iteration to an archive. I'm using vb.net and ...
0
votes
1answer
36 views

Move data with compression

I'm using win 7.I have disk ~2Tb which one I want to format so I need to move data from it to other disk, but the problem is that I have not another 2Tb disk and I think I can compress data(on the ...
1
vote
3answers
181 views

Does 7zip compression level affect decompression speed?

I have a directory that I would like to password protect and encrypt. I am using PeaZip to do this using 7zip compression. I'd like to use the 7z like a directory and hard drive space is not a ...
4
votes
2answers
108 views

How can I specify the order files should be compressed in 7zip?

I have a set of files I would like to compress that I know to be repetitive and compressible, but 7zip chooses a non-optimal order to compress the files and fails to take advantage of their ...
3
votes
1answer
98 views

Is there a way to compress files at different compression levels inside a single 7zip file? [duplicate]

Some files are compressed using their own compression scheme and some aren't. If I try Max compression on an already compressed file, I'll get 1%-2% better compression at most. The amount of time ...
5
votes
1answer
181 views

How to exclude a folder in 7zip?

I want to compress the folder C:\Temp but without a specific subfolder (e.g. C:\Temp\test). How can I do that with 7zip? I've come up with the following command: c:\Temp>7zip a -t7z test.7z ...
0
votes
1answer
68 views

Extracting one file from archive: 7-zip requires decompressing entire archive?

I've noticed that when browsing an archive containing multiple files with 7-zip 9.20 Windows GUI, extracting one file for previewing takes significantly longer with .7z than .rar archives. With .7zips ...
2
votes
2answers
394 views

What does the number after 7-zip's -m switch mean?

7-zip has a command line switch to set the compression method, -m followed by a number, e.g. -m0=LZMA. What does the number (0 in the example) mean? Different numbers produce slightly different ...
0
votes
1answer
222 views

zip sub folders individually

can anyone help me make a batch file for my problem. i have multiple folders that i want to compress individually. root folder 1 file 1 file 2 ...
2
votes
2answers
101 views

What other archive formats save Date Created and Date Accessed?

7-Zip on Windows will save the Date Created and Date Accessed when compressing a .zip file, however it does not do this for its native .7z format. Any Unix-based formats are ineligible. Are there any ...
1
vote
0answers
1k views

7-zip command line -p switch not working according to help page [Solution Found]

I want to be able to automate the encryption of the file type .pcapng in a windows batch script. My current problem is that I get an error when extracting the encrypted file saying something along the ...
0
votes
1answer
231 views

How to create ZIPs with the content of every folder [duplicate]

I have several folders and I need to compress the content of each folder in a separate ZIP file. However, every ZIP should only contain the content of each folder and not the folder itself. The ...
1
vote
1answer
738 views

7zip - compress the contents of each folder in a directory

I basically want to compress each file in each folder, delete the original file and leave the folder uncompressed. I don't want to compress the whole folder, only the contents in it. That, with 7zip ...
4
votes
3answers
3k views

Recursively unzip files where they reside, then delete the archives

I goofed up a setting on the backup software I use. Normally I would have the files from a network share get loaded into a spare drive, compressed into zip folders, then sent off to the offsite hub. ...
0
votes
1answer
370 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 ...
2
votes
0answers
143 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 ...
2
votes
2answers
2k 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 ...
1
vote
0answers
62 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 ...
0
votes
5answers
4k 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 don't compress nothing and sends me this output: System error: ...
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 ...
1
vote
2answers
1k 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
2answers
471 views

How to extract and erase the original compressed file on Windows 7?

I wonder whether there is an extractor tool that as well as extract the file contents, erase the original compressed file. Thank you.
0
votes
0answers
219 views

Is it possible to recover partial compressed files?

Of the most popular compression methods (7z, RAR, Zip, GZip) is there any of them that allows to retrieve the uncompressed data from a partial file? Imagine there is only one compressed file, and it ...
2
votes
3answers
2k views

Why does a zip file appear larger than the source file especially when it is text?

I have a text file that is 19 bytes in size and having compressed the file using zip and 7zip, it appears to be larger. I had a read of the question on Why is a 7zipped file larger than the raw file? ...
34
votes
5answers
3k 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?
1
vote
2answers
560 views

Is there a way to determine the original size or file count of a 7-zip archive?

I know that when I compress an archive with the 7za utility, it gives me stats like the number of files processed and the amount of bytes processed (the original size of the data). Is it possible, ...
7
votes
2answers
4k views

Multithreaded support in 7za

(I posted this first on serverfault, but then I realized it probably belongs here.) I'm trying compress a very large text file using 7za (p7zip) 9.20. The -mmt option doesn't seem to have any effect. ...
1
vote
3answers
9k views

How to compress a JPG image File

I am trying to send an email with an image attachment. But the image size is 40MB and the attachment size can only be 25MB. How can I compress the size of the image so that I can send it via Email?. I ...
14
votes
2answers
35k views

Different compression methods in 7zip: Which is best suited for what task?

So there are different compression methods in 7zip. Which method is best suited for what task? For example: One difference between LZMA and LZMA2 is I can choose all my cpu cores, whereas in LZMA 2 ...
1
vote
1answer
51 views

Extract files to a different folder

On a Windows XP machine, I have a zip file located on "c:\temp\mydata\okidata.zip". Using 7-Zip application, I would like to write a batch script and extract the file silently to the following ...
6
votes
2answers
4k views

How do I use 7-Zip for Windows to create .tar.gz archives?

How can I use the 7-Zip CLI (7za.exe) on Windows to create .tgz archives, as I use tar zcvf archive.tgz source_files on Linux?
2
votes
1answer
366 views

How can I compress multiple files into three files per archive with 7-Zip?

I have 100 files that look like this: 001.txt 002.txt 003.txt 004.txt ..... 100.txt I want to compress them like this: 001.txt 002.txt ----> archive01.7z 003.txt --------- 004.txt 005.txt ...
1
vote
3answers
521 views

Hash of a 7-Zip archive of a SVN export changes even when the files don't change. Is this by design?

I'm writing a PowerShell script that does the following. Does an SVN export of a Subversion repository to a temporary folder Zips the contents of the temp folder into a 7-Zip archive Compares the ...
8
votes
3answers
10k views

How to do “Files to store without compression” in 7-zip?

Is there any way to selectively prevent certain file types from compression in 7-zip, like in WinRAR? I'm trying to compress a huge folder (many gigabytes), and I don't want the already-compressed ...
0
votes
2answers
1k views

Compress big files with 7-zip, and uncompress with WIndows XP WITHOUT 7-zip

I'm using the very latest release of 7-zip to compress some files from the command line on my Windows XP machine. All the small archives work fine... but the bigger ones... always give "invalid or ...
22
votes
6answers
3k views

How can I evaluate the best choice of archive format for compressing files?

In general, I've observed the following: Linux-y files or tools use bzip2 or gzip for distributing archives Windows-y files or tools use ZIP for distributing archives Many people use 7-Zip for ...
9
votes
6answers
17k views

How do I uncompress vmlinuz to vmlinux?

I have already tried uncompress, gzip, and all other solutions that come up as google results and these have not worked for me. To get just the image search for the GZ signature - 1f 8b 08 00. ...
1
vote
1answer
835 views

How can I updated an encrypted 7zip archive without losing encryption?

I created a 7zip archive with AES encryption. I included the option to encrypt the filenames. When I updated the file however I am no longer prompted for a password to open the file and can view the ...
9
votes
4answers
31k views

What are the best options to use when compressing files using 7 Zip?

I often have to gather log files and upload them to a central server (Owned by another company). The central server has a size limit of the file, so I am trying to create the smallest file possible ...
2
votes
2answers
983 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: ...
5
votes
3answers
4k views

Do encrypted compression containers like ZIP and 7-Zip compress or encrypt first?

The discussion of "compress and then encrypt, or vice-versa" led me to ponder the following question: many compression containers, like ZIP, 7z, and rar support encrypting these containers. For ...
0
votes
3answers
3k views

How do I extract .7z files?

Or what do I do with them if not extract them?
2
votes
4answers
867 views

How to get 100% identical compressed files, for source files that only differ in creation date?

I want to be able to compress a file losslessly, and if the original file is identical to another user's file, I want both of our compressed files to match, even if the original file dates are ...