Compression decreases the size of data.

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0answers
9 views

General-purpose program for RLE compression

We have to deal with very large columnar files with fixed-size data and lots of padding bytes coming from mainframe. I would like to evaluate different compression techniques and their impact on ...
4
votes
5answers
14k 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?
0
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0answers
13 views

Gzip Mutliple files using single command [migrated]

Want to Gzip my all the .csv files into a gzip file. I am using this command. gzip *.csv; Problem File contains '//' in its name that's why command is giving error. Error : - '//File.csv' is not ...
114
votes
6answers
14k views

How is PNG lossless given that it has a compression parameter?

PNG files are said to use lossless compression. However, whenever I am in an image editor, such as GIMP and try to save an image as a PNG file, it asks for the compression parameter, which ranges ...
0
votes
2answers
26 views

Best format for compression of large amount of small files

I tried to use .rar and I get a great rate of compression. However it take a lot of time to show the folder structure when I open the .rar file (tried different programs), it looks it is needed to ...
1
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3answers
158 views

Do more compressed PNG images take longer to load?

When I create PNG files with very small disk size, I tend to wonder if the file size becomes less important than the time viewers would need to decompress the image. Technically that would be trivial ...
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0answers
6 views

SASS e images not loaded

I have used webasset and cssmin on a python static site generator to merge 4 css files into a one compressed file. The individual CSS files when referenced individually does contribute to a fully ...
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votes
1answer
28 views

7Zip Zipping up directories

I want to use 7 zip to compress and archive folders but I want it to exclude existing .7z files if they exist and not duplicate them with a .7z.7z ext I found this but it duplicates the already zipped ...
4
votes
1answer
2k 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 ...
1
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4answers
206 views

How to batch compress images with Imagemagick or similar command or program in Linux

I recently learned about the convert command from imagemagick which I have used to compress many pictures that I have for personal use, and for a blog that I have. In my experience, Imagemagick is the ...
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4answers
91 views

Is it faster to compress files before copying? [duplicate]

I have around 80 GB of data I need copy to an external hard drive. Would it be faster to compress all the files first and then copy over? Or would the time it takes to compress and decompress take ...
3
votes
1answer
25 views

How to dump and compress MySQL database in Windows only using command line

Is it possible to backup and compress just like in Linux: mysqldump --all-databases | lzma > all.sql.gz I only have smb:// and cmd.exe access via winexe, so no GUI (remote desktop is not enabled, ...
2
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4answers
3k views

How to hardcode subtitles into an AVI without loss of quality

I am using a program to hardcode subs into an AVI file. The problem is that is recompresses the video using a codec. I don't see why this is necessary and causes a noticeable loss of quality. Is there ...
0
votes
3answers
92 views

How to reduce the size of windows OS Iso file?

I have an Iso file of windows 8.1 pro with December '14 updates. The problem is the file is too big to be burned on a normal 4.7GB DVD , its around 4.8. Now is it possible to remove a few updates so ...
1
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0answers
33 views

Pacmd dynamic range compression Ubuntu 14.04

I used the answer at the link below to successfully set Dynamic Range Compression on my Ubuntu media box running Ubuntu 14.04 (SteamOS session, so no Ubuntu desktop session available). Realtime sound ...
41
votes
8answers
46k views

What’s a good way to extract .rar files on the Mac? [closed]

Anything built-in? (E.g. command line tools.) Any well-regarded software? Update: I like The Unarchiver, but vote up your favourite, or add it as an answer if it isn’t there.
0
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0answers
16 views

LZA Compressor Directory

I am trying to use LZA to compress my directories (No sub folders) Whenever I use it however it automatically creates the archive within an additional folder! Example: I am using a folder called ...
0
votes
0answers
18 views

How to modify files within mszip (cab) executable?

I can list and extract certain executable contents using 7z. It seems to be using standard compression methods. Path = test.exe Type = Cab Method = MSZip How can I modify files inside that ...
4
votes
4answers
4k 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. ...
10
votes
4answers
13k 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 ...
1
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2answers
349 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 ...
1
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1answer
59 views

Extracting a tar.gz file returns, “This does not look like a tar archive.”

I have a tar.gz file and I want to extract it using terminal. I used following commands: tar tvzf ldtp_3.5.0.orig.tar.gz and tar -xvzf ldtp_3.5.0.orig.tar.gz. However, I get the same result for both ...
0
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2answers
468 views

How to update a TAR/Gzip archive

I have compressed a folder using tar like this: tar cvfz folder.tar.gz folder/ Now, say I have changed some of the files in that folder, added some and removed some. And now I want to update my ...
0
votes
1answer
24 views

Is it possible to perform Deduplication recursively?

If anybody is familiar with the concept of Deduplication (If not,read link on wikipedia) http://en.wikipedia.org/wiki/Data_deduplication Is it possible to perform Deduplication recursively i.e. ...
1
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2answers
2k views

How to extract multipart rar with missing parts?

I have a multipart .rar archive containing a single .tar.gz file inside it (don't ask why, that is just how it was made). I am missing a few of the parts, but do have the first part. I would like to ...
0
votes
0answers
54 views

How do I access gzip-compressed data from a PowerShell Invoke-WebRequest command, when the “Accept-Encoding: gzip” header is set?

I'm learning about response compression in IIS and I'm testing my configuration with various tools. It appears that several of these tools either auto-decompress the response, or always send the ...
0
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0answers
33 views

Linux equivalent settings for 7zip

I'd like to use the same settings as below (Win7) on Linux to compress files, but I fail to get equal compression results, for which I blame myself not correctly using 7za. So far, I have 7za a ...
12
votes
4answers
2k views

Why is a FLAC encoded from a decoded MP3 bigger than the MP3?

To be more precise than in the title, suppose I have a MP3 file that is 320 kbps. If I decompress it, then logically, all the data except for roughly 320 kilobits out of each second of audio should be ...
6
votes
6answers
17k views

Reduce .wav file size

I am required by a distance education language course to record some audio and submit it. However, they are being absolutely unreasonable. I am only allowed to attach a file that is 5mb while my ...
-3
votes
1answer
49 views

How is this RAR archive able to achieve such a good compression ratio?

The RAR archive found here (direct download) contains a single AVI video file which is 42MB in size. The RAR archive is only 500KB. How can the archive achieve such a high compression ratio?
0
votes
0answers
30 views

Changes in level of compression between different versions?

I used the save function with xz compression as in save(a, b, file = "c.RData", compress="xz") This produced a file of different size on my disk (11589212 vs. 1162284 bytes) switching from R.3.1.1 ...
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4answers
656 views

Finding out what a file is

I have a compressed file but I don't know what it's compressed with. The extension doesn't give any clue. How can I find out what it is?
1
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1answer
39 views

tar reverse of '--to-command', or: compressing tar entries individually, or: tar with plenty of large files

I would like to create tar gzip archive, but do it the reverse manner of what is most commonly done -- have the files in the archive be compressed individually rather than compress the entire archive: ...
67
votes
4answers
132k 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 ...
1
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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?
2
votes
4answers
143 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 (referring to 7-Zip) native .7z format. Any Unix-based formats are ...
1
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2answers
3k 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.
3
votes
4answers
1k views

Browsable compressed filesystem archive with full attributes?

Maybe a variation of the whole question would be: Are there any other archiving tools than tar that preserve Linux file permissions and user/group flags? I want to create archives of a directory tree ...
1
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0answers
54 views

Why do IPSec VPN Compression and Windows Remote Desktop not work together?

I just discovered a strange problem. I connect to a remote network via VPN. Within this VPN is a separate Microsoft Small Business Server (which does not provide the VPN, another device does this). So ...
1
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1answer
23 views

Deleting unpacked tar.gz files after unpacking incorrectly

I recently unpacked a set of backup files in RHEL3 - 2.4kernel with tar via: tar -xvf backupfile It started to error out a bunch and I aborted thinking that maybe it was a gzip instead. Unpacking ...
2
votes
1answer
37 views

How to open multiple TGA files then save them compressed as 24 bits in Photoshop?

I have a huge amount of TGA files from the game Counter-Strike (environment files such as sky, grass, water etc) and they are pretty big. There were some other TGA files that I manually opened and ...
3
votes
2answers
983 views

20GB+ worth of emails in my /home what is a better solution for that?

My email storage requirements are outgrowing anything reasonable with respect to local mail storage. As we speak 99% of my home partition is filled with personal mail in Thunderbirds mail dirs. ...
3
votes
3answers
2k 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 ...
3
votes
1answer
189 views

Not sure gzip has decompressed the whole file

I am decompressing a list of files using gzip: At any time it skips from one file to the next, I read (I am using the verbose option): star_60out.txt.gz: 91.0% -- replaced with star_60out.txt or ...
0
votes
0answers
24 views

Is there an alternative to httpfs2 to mount web urls in Linux?

Currently I use httpfs2 to mount direct web urls in the filesystem. For example a rar archive which has to be decompressed, but I don't have enough space on my VPS to download AND then decompress the ...
0
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1answer
60 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 ...
1
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0answers
34 views

Which are good compression formats for an eternal version of a logfile? [closed]

I'm experimenting with logrotate and trying to set up an eternal version of a high volume logfile, e.g. /var/log/syslog, i.e. all entries should be preserved from the second the OS (Ubuntu 14.04) ...
2
votes
2answers
411 views

7 zip archiving directory recursively

I zipped my old windows dir with 7 zip. It zipped the "Application Data" many time (hundreds) as shown here : C:\Windows.old\Application Data\Application Data\Application Data\Application ...
12
votes
5answers
11k views

.tar files without directory structure

I'm .taring some files with the path example/super_user/Output.*. The resulting .tar looks like this: + example + super_user - Output.zip - Output.xml - Output.txt ...
0
votes
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 ...