Shrinking (compressing) and restoring (decompressing) of data.

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37 views

linux unbuffered compression options

I'm working on a embedded system and due to persistent memory restrictions, I need to compress a log file "on the fly". My objective is to have a one liner inside a script, which would look like ...
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2answers
28 views

Squashfs minimal compression?

I'd like to create a squashfs image of a directory, but it's a huge one and even minimal compression would be a big win. Is there a way to do something like mksquashfs -1?
2
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1answer
21 views

Is there a compression method that supports solid compression and also adding data to the compressed file?

I have a large compressed .tar.xz file containing log files. The compression ratio is very good - but it takes a long time to compress, and if I want to add additional log files to it, I have to ...
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0answers
19 views

On-the-fly decompression

I have 44 TB worth of gzipped files that are 1.5 GB each when compressed or 2.0 GB when uncompressed. I have a tool that can read only uncompressed files. I would like to avoid the overhead of ...
1
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1answer
42 views

log compression using logrotate

I was trying to set compression for jboss log files. The log files I want to compress are console.log and server.log. Compression for console.log is working fine, but server.log I am seeing issues. I ...
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2answers
63 views

Tar big files in different directories

I have ~20 files, each about 10 GB in size, in different folders that I need to compress into a single tar. It is not practical to copy them all to one location. More precisely, the files are ...
0
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1answer
44 views

Compressing files using p7zip from the command-line

I would like to compress four ISO files using 7z into a new archive called ISOs.7z from the command-line on my Sabayon machine. These are the commands I have tried so far (I know none of these specify ...
0
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1answer
29 views

Verify files AFTER extracting gzip

I gzip a folder, transfer it to a remote location and then extract it to a folder. The problem is that this machine is a little unreliable and sometimes writes don't succeed and there can be zero-byte ...
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2answers
102 views

Extract compressed file by it's header as it is piped from stdout (locally or from remote location)?

I am sending compressed file with piping either local or from a network location. And on the receiving end, I would like to detect the type of compression and use the appropriate decompression utility ...
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1answer
68 views

How to convert tar.bz2 to .bz2?

I have a file with compression tar.bz2 , I would like to convert it to .bz2 . Is there a command that does this in one shot? I tried the below but no joy ! tar -xvjf US.tar.bz2 US bzip2: ...
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3answers
67 views

How can I keep rsync from using encryption and compression for the file transfers after the connection is authorized?

I understand that a secure connection (i.e. ssh) is needed to authorize a connection to the remote server. But after that is authorized can the data be transmitted without encryption and compression ...
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1answer
122 views

Get compressed size of piped output with gzip?

To get uncompressed size of already compressed file, I can use -l option in gzip utility: gzip -l compressedfile.gz However is there a way to get size of compressed file if I am piping the output? ...
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4answers
2k views

How to know how much space an uncompressed zip will take

Given a (really long) list of zip files, how can you tell the size of them once uncompressed?
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1answer
52 views

Browser (HTTP client) with support of bzip2 or lzma2 compression?

What browsers (HTTP clients) support HTTP compression using bzip2 or lzma2? (HTTP compression for page requests) I have only heard of Firefox patch, but I am not sure if it actually supports ...
0
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1answer
22 views

Generating files of varying variability?

I have used /dev/zero and /dev/random to generate files of certain size. However, is there a way to control variability of generated files? I would like to create few files that would have same ...
4
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3answers
146 views

How can I change the first line of a big gzip file without decompressing all of it?

I currently have a compressed file, A.gz which contains lots of tabulated data, including a header in the first line. I want to create another file, B.gz, which has the same data as the previous file, ...
0
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1answer
106 views

What is the highest compression ratio compressor for pdf, djvu, and images

Comments so far have not been specific with the type of files they needed to compress and didn't reach a definitive answer I have a 1 TB hard drive full of pdf,djvu mostly and the rest are images and ...
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0answers
31 views

How do I create a deflate file suitable for HTTP?

Say I have index.html. How do I obtain index.html.deflate appropriate for serving through HTTP with the "deflate" encoding? I am coding a simple web server and I don't want to implement streaming ...
4
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3answers
331 views

Compression / archiving that keeps permissions and file owner?

I know that similar questions have been asked about permissions, but which form of compression or archiving keeps the permissions and file owners of each file and directory? I was considering the ...
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3answers
671 views

What does the `-C` flag exactly do in `scp`?

I always use either rsync or scp in order to copy file from/to a remote machine. Recently, I discovered in the manual of scp (man scp) the flag -C -C Compression enable. Passes the -C flag to ...
0
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0answers
191 views

where to compress=lzo, btrfs with virtual disk images, with their vm's internally using btrfs

I've been using compress=lzo on my btrfs volumes, because I read this fast compression method actually increases drive performance. (Haven't tested myself.) I'm starting to use ...
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4answers
1k views

Is it possible to make a .tar.gz file directly from stdin? Or, I need to tar together already gzipped files

I'm going to tell you exactly what I need in order to clarify the cryptic question in the title. I'm currently making scheduled MySQL backups of all my databases with something like: mysqldump ... | ...
2
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1answer
179 views

How to reduce size of a FLAC file without damaging its quality?

I got collection of vinyls which I paid for them to be digitized in FLAC. However my Hard Drive is getting full (91% full as of today) and the smallest of these vinyls is 2.3 GB in size! I would ...
0
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1answer
97 views

Can I use lzma compression, without using “tar”, on OSX 10.10.3?

I kind of think of OSX as Unix by another name. But, if I need to move this to the Apple forum, please tell me! I can create tar files compressed using lzma as such: $ ls ./DbDumps alpha.dmp ...
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3answers
395 views

Does gz compression ratio improve over time?

I have some process that creates a stream of millions of highly similar lines. I'm piping this to gz. Does the compression ratio improve over time in such a setup? I.e. is the compression ratio better ...
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2answers
38 views

How to open compressed file in less mode [duplicate]

How do I open a compressed file in less mode. I am able to grep using zgrep and using zcatI can open, but the file is big I want to open in less mode.
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3answers
477 views

Can tarring files improve compression?

Can tarring a bunch of files together improve compression with the standard tools, e.g. gzip, bzip2, xz? I've long thought this to be the case but never tested it out. If we have 2 copies of the same ...
0
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1answer
390 views

Compress multiple files and keep their name?

I have hundreds of .csv files that I need to compress into one file each. It should look like this originalname.csv.gz
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0answers
21 views

Pipe gzip output to Bluetooth transfer?

How do I pipe gzip output to Bluetooth transfer? I am able to send send file over Bluetooth using this command: bluetooth-sendto --device=12:23:35:96:45:45 file.tar However, piping gzip didn't ...
13
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9answers
3k views

Memory problems when compressing and transferring a large number of small files (1TB in total)

I have 5 million files which take up about 1TB of storage space. I need to transfer these files to a third party. What's the best way to do this? I have tried reducing the size using .tar.gz, but ...
2
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1answer
53 views

lrzip compression does not shrink random data

I'm trying to shrink down some big files around 3.0 GB each and I decided to use lrzip after seeing a few benchmarks and such however is it something I'm doing wrong or something as whenever I run ...
8
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2answers
519 views

Create a gzip file of a predetermined size

I want to test an upload of files of content type application/x-gzip of various sizes ranging from 100 MB to 999 MB. How can go I about creating .gz files of these predetermined sizes? If I do dd ...
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3answers
5k views

How do I compress files in-place?

I have a machine with 90% hard-disk usage. I want to compress its 500+ log files into a smaller new file. However, the hard disk is too small to keep both the original files and the compressed ones. ...
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1answer
540 views

unpigz (and untar) to a specific directory

I know how to gunzip a file to a selected location. But when it comes to utilizing all CPU power, many consider pigz instead of gzip. So, the question is how do I unpigz (and untar) a *.tar.gz file ...
7
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2answers
724 views

How to store a large folder in a single file without compression

Sorry if this is a stupid question, but I want to take a 78gb folder and store it in a single file (for upload into a cloud service), as if I am compressing it in an archive, but I don't want any ...
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1answer
70 views

Erratic behavior with gzip on unix

I am compressing log files daily and very recently I have been seeing some crazy results on the file type of the file after compression. Normally you would expect file filename.gz returning gzip ...
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7answers
36k views

How do I grep recursively through .gz files?

I am using a script to regularly download my gmail messages that compresses the raw .eml into .gz files. The script creates a folder for each day, and then compresses every message into its own file. ...
0
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2answers
389 views

Gzip file but excluding some directories|files and also append current date

I'm looking for a way to create a .tar.gz file from a directory but I have some doubts. I'm know that the command for create the file is: tar -zcvf /path/to/compressed/file.tar.gz /path/to/compress ...
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1answer
213 views

Handle compress command error messages on AIX

I am working on production issue and unable to reproduce error message for compress command. Current Solution We have case-esac block in shell wrapper that handles messages as follows; case "$MSG" ...
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3answers
720 views

How to compress the directory and its contents

How do I compress a directory and its contents in ksh on AIX for a file I do compress filename
5
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2answers
140 views

How do I layer compression on top of encryption on top of BtrFS, per-file?

BtrFS should support this really, but it doesn't. So ECryptFS looks like it will fill the gap. The only thing is, how would I layer compression on top of this? Reasons for compression on top of ...
7
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3answers
3k views

Unpack file compressed in .txz and .tar with one command

I have a file compressed in *.txz. After unpacking it I received a *.tar file. Is there any way to unpack it twice with one command? I mean unpack file (*.tar).txz with one command? For know I'm do ...
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0answers
116 views

Errors when installing Maldet on an Fedora 20 system, have had these before

I just installed maldetect-1.4.2 on a system(Fedora 20) and it gives this error when installing: gzip: stdin: unexpected end of file tar: Child returned status 1 tar: Error is not ...
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2answers
2k views

Fastest way of working out uncompressed size of large GZIPPED file

Once a file is gzipped, is there a way of quickly querying it to say what the uncompressed file size is (without decompressing it), especially in cases where the uncompressed file is > 4GB in size. ...
1
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1answer
125 views

Is there a difference between gunzip -c and gunzip in terms of system utilization?

Is there a difference between zcat/gunzip -c and gunzip apart from the obvious one that one outputs it to the terminal and the other decompresses it to a file? I'm looking from a CPU utilization ...
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2answers
724 views

How strong is the encryption of a zip file in Linux Mint

Zip encryption has had often a bad reputation of being weak, but some would argue that a zip file encrypted using certain algorithms (such as by using AES), together with strong password, is really ...
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2answers
401 views

Tell gzip/bzip2/7z/etc not to compress already-compressed files?

I'm tarring up /home, and piping it through bzip2. However, I've got lots of already-compressed files out there (.jpg, .mp4, .mkv, .webm, etc) which bzip2 shouldn't try to compress. Are there any ...
2
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1answer
201 views

Is there any size limit for the compress command?

Is there any particular size limit after which the compress command works? As I know for 0 byte file, the compress command does not work. But today I tried to compress a file of byte size 27 bytes ...
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1answer
653 views

How to compress a single huge file (e.g. 200GB) file from command-line [closed]

I'd like to compress one huge file (~200GB) from the command line. no need for archiving its directory along with it, swift operation and high compression ratio preferred. What may be some good ways? ...
0
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2answers
280 views

How to zip folder content on Ubuntu without keep the folder structure(path)

How can I compress a directory content without compress the full path folder structure too. I am using this command to zip a folder content under var/www/ directory, but when I unzip the ...