Questions tagged [compression]

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

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How to verify size of pigz (parallel gzip) archive contents? [duplicate]

I created some pigz (parallel gzip) - home page - compressed archives of my SSD disk drives. (compiled version 2.8) I called one of them 4TB-SATA-disk--Windows10--2024-Jan-21.img.gz which says the ...
Vlastimil Burián's user avatar
9 votes
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What free tool does Nautilus use to extract RAR files?

I have noticed that Nautilus (GNOME Files) can extract some RAR files that cannot be extracted using free packages like unrar-free or file-roller via CLI, nor using GUI tools like Engrampa or ...
tagomago's user avatar
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3 answers
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Is it possible to obtain .tar from .tar.bz2?

I need to extract a specific folder from .tar.bz2 (34G). The issue is that it takes 1 hour. I guess that this is due to the compression. I guess that w/o compression extraction of a specific folder ...
pmor's user avatar
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Accurately monitoring RAM and swap usage while running zswap compression

I'm running zswap on 6.2.0-39-generic (Ubuntu 22.04, HWE). My understanding is that zswap intercepts pages marked for swap, compresses them (if possible) and stores them in a compressed section of the ...
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Failed to run init with error: jffs2: compression type 0x06 not available

I am working on an embedded Linux system (5.10.24), and I am using jffs2 as the rootfs. Now I changed the kernel configuration of jffs2 as follows, # CONFIG_JFFS2_FS_WBUF_VERIFY is not set # ...
wangt13's user avatar
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Can't install zstd on ol6

Is there a way to install the Zstandard compressor on Oracle Linux 6.10, or only since OL7 version? On OL7 version, I've discovered that zstd resides on "Optional Latest" repository. But, on ...
Alan Homobono's user avatar
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compress multiple files at once but don't put them all into one file?

I want to compress multiple files at once (one command) but I don't want to put them into same directory or same file. How'd I do it?
achhainsan's user avatar
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Creating a compressed image of an exFAT USB drive using dd

My system is running Ubuntu 22.04.3 LTS. I plug a USB drive into that system. That USB drive (/dev/sdb) contains an Ubuntu installation, mostly in an ext4 partition (/dev/sdb3). That installation ...
Ray Woodcock's user avatar
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Recursively xv compress each file in multiple subdirectories?

I have multiple directories and subdirectories, with files inside. I would like to recursively compress each file in these (sub)directories with xv (xz -9ze -T0) which are not .xv files yet, without ...
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OCR high res images & combine OCR data later, after image compression?

I have a large number of .tif's coming out of ScanTailor. Is there a way that I might OCR those .tif's with tesseract, holding the OCR data separate from the images; then compress the images, and ...
Diagon's user avatar
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How can I evaluate tars and gzips for validity without expanding them?

LONG ago I wrote a backup script for our site and have updated it ever since. However, occasionally things go wrong and some of the older backups are now broken. In days gone by I had used the utility ...
Richard T's user avatar
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What file compression software/algorithm is best for mixed types of files? [closed]

I am looking to backup a large amount (~400GB) of different types of files (50% images and videos, 30% audio, 20% text). I hesitate to give an amount by which I'd like the size to be reduced, since I ...
Lukas's user avatar
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2 votes
1 answer
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Merge the split file vs Original compressed file

On Ubuntu 22.04, I found these 2 methods will get different sha256 of archive_tgz tar czf /a/archive_tgz . tar czf /dev/stdout . | split -d -b 200M - /a/archive. && cat /a/archive.* > /a/...
Azreal's user avatar
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Download a file and piping to uncompress is not as fast as expected

I need to download and decompress a file as quickly as possible in a very latency sensitive environment with limited resources (A VM with 1 cpu, 2 cores, 128MB RAM) Naturally, I tried to pipe the ...
Richard's user avatar
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btrfs configurations for various subvols

Is there a recommended for how much to compress various subvolumes based on their use purpose? In my case, I have subvols @, @home, .snapshots/@root, .snapshots/@home, @srv, var/@log, var/@cache. This ...
squirrels's user avatar
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How can I have rotated log files without a numbered suffix using Linux logrotate?

I have on my server more file rotate, but when I want to compress it, i Have an extension 1.gz, but I just want .gz These files are automatically rotate by the application: server.log.2023-03-16 ...
sam's user avatar
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1 vote
1 answer
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ZFS - Why do compressed files show disk usage of nearly double the apparent size?

Using FreeBSD 11.1-STABLE, I have a ZFS dataset configured with gzip-9 compression, as well as a recordsize of 8K. (This volume is for archiving of small files, not speed.) zfs get all pool02/...
s.co.tt's user avatar
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10 votes
1 answer
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Issue viewing compressed file with "zless", but not with "zmore" or "gunzip -c"

On my FreeBSD 13.2 system, the zless utility cannot view text files compressed with gzip or compress, warning that they may be binary files and then showing garbage if I say I want to see the contents ...
Kusalananda's user avatar
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Unrar all .rar files in a directory to a folder with the same name

Here is an example of what I am trying to do: I have a folder (called 'dir') that contains the following: dir |_sub1.rar |_sub2.rar |_sub3.rar I will cd ~/ to dir and want to run a command that will ...
linuxuser24569's user avatar
3 votes
1 answer
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How to compress disk swap

I am looking for a way to compress swap on disk. I am not looking for wider discussion of alternative solutions. See discussion at the end. I have tried... Using compressed zfs zvol for swap is NOT ...
linuxlover69's user avatar
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Is possible compress and uncompress a file with a password but considering an expiration date too?

In Linux about compression files can be accomplished with the tar and zip/unzip commands, perhaps more. I know that is possible establish a password protection for security reasons. The question is: ...
Manuel Jordan's user avatar
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What POSIX utility can I use to decompress files with the .xz extension?

Instead of using non-POSIX tools such as unxz, what POSIX utility can I use to decompress files with the .xz extension? Neither xz nor unxz is a POSIX command, so if I want to run only POSIX commands, ...
just_another_human's user avatar
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Symlinking a .desktop files compresses the file

I am trying to install an application needed for my university. Whenever I am trying to symlink the .desktop file from original folder, it somehow compresses it and then puts it in the .local/share/...
0xKnR's user avatar
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Normal gz file not extractable by tar [duplicate]

I have a gz archive but for some reason tar said that the format is incorrect even though I can double click it in mac Finder and extract it normally, and file command shows the same format just like ...
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btrfs mount with compress fails with udisksctl but succeeds with mount?

$ sudo mkfs.btrfs -fL borgbackups /dev/vgxubuntu/borgbackups $ udisksctl mount -o compress=ztsd:15 -b /dev/mapper/vgxubuntu-borgbackups Error mounting /dev/dm-3: GDBus.Error:org.freedesktop.UDisks2....
eugenevd's user avatar
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See the file name and size within a (.Z) compressed file without uncompressing it

I have tons of .Z compressed files scattered across various directores and need to see the size of the file within it. I don't plan on uncompressing all the .Z files. Is there a way to see the content ...
Steve237's user avatar
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Winrar error: Attempting to correct the invalid file or folder name

Posting this since I could not find it using Google and this took weeks. When extracting using Winrar, I am getting ! Attempting to correct the invalid file or folder name ! Renaming C:\Users\noam.s\...
Gulzar's user avatar
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Extract first n bytes from .tar.gz and output as a .tar.gz in a single command

I have a .tar.gz as input and want to extract the first 128 MiB of it and output as a .tar.gz in a single command. I tried: sudo tar xzOf input.tar.gz | sudo dd of=output bs=1M count=128 iflag=...
JohnnyFromBF's user avatar
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How to extract subdirectory from tar into another tar without `sudo`?

Given A tar file with rootfs where all permissions and ownerships are set. Expected A tar file with content of subdirectory, let's say usr/local/lib where permissions and ownerships are retained. ...
Michał F's user avatar
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Are .DAT files the same as compressed files in Unix?

Please confirm if .DAT extension files are the same as compressed format files (.zip ) in Unix. As I try to use gzip filename.DAT then is the original 2 GB file size the same after compression? Is ...
kumar's user avatar
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4 votes
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How do you ssh using zstd dynamic compression?

I want to set up my ssh tunnel to do dynamic compression so that I get maximum throughput for the bandwidth and CPU resources I have available on each end. Since gzip compression is built-in and not ...
ChinnoDog's user avatar
2 votes
2 answers
599 views

Compression, and a disk image of a LUKS container

I have a dd image of disk, which is a LUKS container containing a filesystme, and which I can loop mount and unlock to access the files. The filesystem in the container is only about 1/4 full. What ...
Diagon's user avatar
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1 answer
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Most portable decompression file format, and command

Looking for a file format that is guaranteed to have a decompression command preinstalled on all POSIX Unix/Linux installations. The .Z file can be decompressed by uncompress. But am not sure if ...
codepoet's user avatar
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Common practices for backup compression levels

This question may be a bit "opinion based", but please consider it as looking for authoritative source of information on the use of compression levels. I have a server with few databases ...
Kamil's user avatar
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"gzip: stdin: unexpected end of file" after using tar with split

I have a folder of roughly 600MB of images in a folder output_test. I then create 100MB chunks of tar.gz files using the following command: tar -czf - output_test/ | split --bytes=100MB -d -a 3 - ...
Martin Müller's user avatar
7 votes
4 answers
544 views

Record count and cksum on compressed file

There is a file of 40 GB in gz format. I want to find the record count and cksum of this file in uncompressed format. One approach I have is: Unzip the file using gunzip Use wc, cksum commands on ...
Gopi's user avatar
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1 vote
1 answer
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Compressing an archive of images does not reduce its size significantly

I have lots of pictures to back up from my computer to an external hard drive. I want to make archives of all picture folders I want to back up and compress them to save space on my external drive. I ...
Wapax's user avatar
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3 votes
1 answer
356 views

tar lzma autocompression produces the error "This does not look like a tar archive"

The following script mkdir test && cd test mkdir files touch files/{1,2,3} tar --create --file "test.lzma" files/{1,2,3} --auto-compress mkdir extracted_files tar --extract --file &...
cppbest's user avatar
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0 answers
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How to do a transparent compression of a folder on Debian, Ubuntu and Linux Mint? [duplicate]

Its known, its possible to compress complete file systems by useing p.e. btrfs. Also known it`s possible to compress p.e. Ext4 and some other file systems inside a .qcow2 useing VM. See follow: How to ...
Alfred.37's user avatar
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0 answers
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How can i use ffmpeg to compress a .mp4 ( h264 ) to a smaller size without quality loss? [duplicate]

Hello i am kinda new with ffmpeg and learning everyday, i am now looking for on how i can compress a video in a smaller size. since i have some 1920x1080 mp4 files with a rediculous high size. For ...
Sam van Viegen's user avatar
0 votes
1 answer
3k views

How to run zlib from terminal on Ubuntu?

I've installed zlib1g but still zlib isn't available from the terminal. How can I find the executable to run it? Or is there an easier way I'm overlooking? The reason for this is that I want to ...
Slbox's user avatar
  • 261
2 votes
1 answer
660 views

How do I view contents of initramfs.img in Debian-based distributions?

I often have open questions regarding the booting of a machine with GNU/Linux installed. In such cases, it could be helpful to view which files are present in the initramfs image. I have googled for a ...
Mikke Mus's user avatar
  • 143
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0 answers
24 views

How to mount a compressed file for random reading? [duplicate]

I have a large disk image that I don't need to access now, but I might in the future. I'd like to compress it, but without needing to fully decompress it to read it. If I compress it with an algorithm ...
Danya02's user avatar
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2 answers
339 views

How to use jpegoptim to have files only 20kb in size?

I have tried using jpegoptim and even tried the manpage but am stumped. Here is a file I want to reduce to 50k and even open to reducing quality of the data - Image: Filename: shirish.jpg Format: ...
shirish's user avatar
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-5 votes
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Why are zips still used even when kernels compress files by default?

Why aren't .zips obsolete, now that most, if not all, modern kernels support on-the-fly compression?
outlandish's user avatar
1 vote
1 answer
897 views

How to extract all uncorrupted file from bzip2 compression?

I am trying to uncompresss a bzip2 file (~55 GB) with the command tar -jxvf file.tar.bz2 However I found that the decompression process gets stuck at a certain file and, after waiting a long duration, ...
Raghvender's user avatar
-1 votes
1 answer
2k views

How do I extract a .tar.xz file? [duplicate]

Some software seems to be distributed in a new archive format: $ file node-v18.7.0-linux-x64.tar.xz node-v18.7.0-linux-x64.tar.xz: XZ compressed data How do I extract this, preferably using tar (like ...
mikemaccana's user avatar
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1 vote
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Compressing small files with gzip makes its size smaller than with bzip2, why? [closed]

I have a question, just a little thing couch my eyes it's about compression with gzip and bzip2: If I understood correctly - bzip2 requires more processing power but compresses files smaller and more ...
Karuch's user avatar
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1 vote
2 answers
526 views

Looking for a linux backup tool multithreaded with encryption and good compression algorithm

I am looking for a linux backup tool to upgrade my backup strategy. Today I do full backups everyday on Linux server (Ubuntu 20.04). I prefer to backup data directly inside our VMs and send to another ...
moe69230's user avatar
1 vote
1 answer
352 views

Why GZIP utility cares about extension?

Whenever I need to decompress a file which was compressed with Gzip, I need to rename the file with a .gz extension , I tried other compression utility like zip, bzip2 and they don't seem to care ...
pwnr007's user avatar
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