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2
votes
1answer
28 views

cpio VS tar - what the best archive solution in order to compress hundred of directories to one file

I have hundreds of directories under /var/Recording, and each directory there will have subdirectories, including files, hard links and soft links. I want to compress all directories under ...
0
votes
0answers
22 views

What does “GLib-CRITICAL” error mean? [duplicate]

I'm trying to working with complearn, I installed complearn- toolkits , gui etc. from terminal window. Now I'm trying ncd (normalized compression distance) code samples to find similarity distance ...
1
vote
1answer
2k views

Trying to compress avi file using ffmpeg

I used the command below to compress an avi file(using ubuntu) ffmpeg -i input.avi -vcodec msmpeg4v2 output.avi but I am getting these errors Incompatible sample format 's16' for codec 'ac3', ...
1
vote
2answers
20 views

Unzip error, is recovery possible?

I compressed 4 separate folders with some wedding videos (!!) a few months ago. Today I tried to unzip them, and had no problem with the last 2, but the first 2 of them show an error: ...
9
votes
5answers
7k views

Which file compression software for linux offers the highest size reduction? [closed]

I do a ton of file compression. Most of the stuff I am compressing is just code, so I need to use loss less compression. I was wondering if there was anything that offers a better size reduction ...
2
votes
1answer
2k views

Clear unused space with zeros (btrfs)

How to clear unused space with zeros ? (I am asking for tool for btrfs filesystem) I'm looking for something smarter than cat /dev/zero > /mnt/X/big_zero ; sync; rm /mnt/X/big_zero Like ...
7
votes
3answers
666 views

How to recompress 2 million gzip files without storing them twice?

I have about 2 million (60GiB) of gzipped small files and I would like to create a compressed archive containing all of them in an uncompressed version. Unfortunately, I cannot just uncompress them ...
0
votes
1answer
30 views

Why scp with compression takes longer than without compression

I was playing around and noticed that secure-copying with compression takes longer than without compression time scp -C ./test.sql user@vmware:/home/user real 0m42.758s user 0m40.455s sys ...
2
votes
1answer
20 views

Is it possible and how to merge identical files between different snapshots in a btrfs file system?

I regularly use btrfs's snapshot to backup the whole system, but it's redundant to have identical files between different snapshots. Commonly, for example, I took a snapshot of @ as ...
1
vote
1answer
41 views

How to check if SSH compression is enabled?

I am experiencing severe slowdown in Git checkouts from VM. I've been told that one of the reasons may be SSH compression (either enabled or disabled). How to check that is the state of compression ...
2
votes
1answer
39 views

Compress a tar file without extracting the content

Is it possible to compress a tar file such that I don't end up with an archive file in an other archive file but just an archive file containing my content fx. a tar.gz file? I don't want to extract ...
2
votes
2answers
86 views

Estimate compressibility of file

Is there a quick and dirty way of estimating gzip-compressibility of a file without having to fully compress it with gzip? I could, in bash, do bc <<<"scale=2;$(gzip -c file | wc -c)/$(wc ...
0
votes
0answers
93 views

Private VPN compression for faster internet

I've posted this same question on StackOverflow as well, but figured out I may get more Debian-specific answers here Background: I'm a student, and currently the WiFi connection at my school is very ...
2
votes
1answer
216 views

Zip does not compress files when zipping

I have zipped a file recursively in a directory. But what I notice with these last few zips is that the files do not get compressed. adding: ...
7
votes
3answers
11k views

Is it possible to compress a very large file (~30 GB) using gzip?

Is it possible to compress a very large file (~30 GB) using gzip? If so, what commands, switches, and options should I use? Or is there another program (preferably one commonly available on Ubuntu ...
3
votes
2answers
67 views

In what situation would a tarball (.tgz) be almost the same size as the original

I just tarballed a dump of some websites (configs, image directory, css directory, and site content (html files etc)) using tar czf sitedump.tgz backup_folder/. The original "backup_folder" was about ...
0
votes
2answers
52 views

Why don't the servers use 7z?

By default on a UNIX machine install, I can see the logs are rotated with gzip. Question: Why doesn't the UNIX world use by default 7z? It would be much more efficient than gzip.. I just compressed ...
6
votes
1answer
65 views

How should I combine many compressed files into one archive?

I have a few hundred .tar.xz files which are almost identical (they are daily database dumps, and the database changes slowly). I believe that due to the similarities in the uncompressed files, they ...
2
votes
1answer
152 views

How to compress a TMPFS folder?

I'm looking for a way to compress a tmpfs folder on the fly. I would like to use it for a local cache folder with a lot of data. I know there is a way to use Redis with eg LZF compression, but I ...
2
votes
1answer
35 views

Disk usage inside archives, like ncdu

I am a fond user of the ncdu utility to figure out how space is used within a directory. However, I have a use case where I am trying to choose which folders to backup and which folders not to ...
5
votes
1answer
195 views

Command-line incremental backup tools

Which command line backup tool(s) has the best compression ratio? I want to backup my entire system, including media files, text files etc. I found this list on the Arch wiki site but I don't know ...
23
votes
5answers
17k views

Is it possible to mount a gzip compressed dd image on the fly?

I like create an image backup for the first time I'm backing up a system. After this first time I use rsync to do incremental backups. My usual image backup is as follows: Mount and zero out the ...
2
votes
1answer
54 views

How can I tell when a file was compressed?

I want to find out when my log files were compressed by logrotate because when I received them from cron in my email, the logs came in as text in the main body of the email instead. I did: ls -1la ...
3
votes
1answer
104 views

zfs-fuse: enabling compression has no effect

I installed on Debian Wheezy zfs-fuse file system and enabled compression gzip-9 on one dataset ("storage/backup"). When I check if the compression is enabled on this dataset, it shows YES: $: zfs ...
2
votes
1answer
27 views

appendable and greppable archive on CentOS to hold many log files (logrotate on steroids)

I have a bunch of applications on a CentOS 6.3 box, which generate daily logs (text files with a very similar content) in this vein: /data/logs/app/my-2014-06-29.log ...
3
votes
1answer
2k views

How to extract files from uImage?

Buildroot is generating Images for an embedded device where they should run on. This is working very well. In those Images the rootfs is included. Due to some research I'd like to look into that ...
0
votes
2answers
138 views

Mount compressed tar file and update it

How do I mount a .tar.gz file, update it (add new files, edit files), and then unmount it such that changes are reflected in the original compressed file? I'm open to other compression formats if no ...
1
vote
1answer
59 views

Compress memory on low Ram VM

Is there a way to get out more out of your limited Ram on a VM? I have a VM running on a cloud hoster and try to optimize a quite low on RAM mashine. I heard, there is a way to compress parts in the ...
0
votes
2answers
156 views

How to install Uglify on Debian Sid

I have a question about how to install Uglify or Uglify2 on Debian. I'm also wondering whether I have to install Node.js as well. My main goal of asking this question is to minify all my CSS and .js ...
1
vote
1answer
90 views

Using `tac` on zipped files

tac unzipped.log | grep -m1 pattern works perfectly fine but I am not able to use the tac command on zipped files. tac zipped.gz | zgrep -m1 pattern returns nothing. Is there anyway to use tac ...
2
votes
0answers
38 views

Image set compression

Is there a good open source (not exclusive to Linux) for compression of a set of similar images? I have thousands of documents scanned but I do not access them often. The documents are forms, with ...
2
votes
2answers
134 views

Compress zip files with higher compression

I have a large number of zip files that were compressed using the zip command. I would like to recompress them with the -9 flag to improve the compression ratio. Does anyone know if that can be done ...
2
votes
2answers
323 views

Making tar split archives as it compresses?

I want to compress a file with tar but I'd like to know if its possible to do it while splitting the files. I know that in windows is possible to do this with winrar, I also know I can use split but ...
2
votes
1answer
75 views

Can p7zip create smaller zip files than winzip?

7-Zip for Windows creates smaller zip archives than WinZip, so presumably P7zip can create smaller zip archives than Zip in Linux. So how do I create zip files using P7zip in Linux?
17
votes
3answers
2k views

Does tar actually compress files, or just group them together?

I usually assumed that tar was a compression utility, but I am unsure, does it actually compress files, or is it just like an ISO file, a file to hold files?
37
votes
1answer
2k views

What happened to bzip1?

bzip2 had been a de facto standard for quite strong compression throughout many years already. I myself had typed the bzip2 command thousands of times already, which makes me wonder - what happened to ...
6
votes
1answer
156 views

How to specify additional parameters for GNU sort's --compress-program option?

sort --compress-program=/bin/gzip works fine, but how can I pass options down to the compression programm (e.g. --best or --fast)? sort --compress-program=/bin/gzip\ --best failes with the error ...
18
votes
4answers
13k views

Clear unused space with zeros (ext3,ext4)

How to clear unused space with zeros ? (ext3,ext4) I'm looking for something smarter than cat /dev/zero > /mnt/X/big_zero ; sync; rm /mnt/X/big_zero Like FSArchiver is looking for "used space" ...
8
votes
4answers
13k views

How to uncompress zlib data in UNIX?

I have created zlib-compressed data in Python, like this: import zlib s = '...' z = zlib.compress(s) with open('/tmp/data', 'w') as f: f.write(z) (or one-liner in shell: echo -n '...' | python2 ...
5
votes
1answer
150 views

Is there any way in BTRFS to set compression permanently?

I have a USB HDD. I want to mount it with compression enabled. I can do in the fstab of my system or even using udev rules. The problem is that I won't mount my USB HDD on my computer only. Up to ...
1
vote
2answers
34 views

bzip2 -c versus -z

Wanted to check for understanding; while revisiting the topic of using dd over netcat I experimented with compressing the data with bzip2. In the man page, there's -c (compress or decompress to ...
2
votes
2answers
721 views

How can I tell if PPP compression is enabled for modem?

I'm using Debian Linux on an embedded system, we use ppp to connect to the WAN via a CDMA modem. I want to find out if compression is being used by ppp. In my /var/log/messages I see the line: ...
1
vote
1answer
1k views

Error with a .gz file decompression in Mint, but works perfectly in Windows, so the file is not corrupt

I've downloaded some .csv files from the OECD Stats website, since I need them to plot some graphs with gnuplot. When I open them with File Roller 3.4.1 (the default program to handle archive files), ...
2
votes
1answer
153 views

Compressing all files that contain a particular string

How can you compress all files in a directory that contain the word “compress” anywhere within its contents?
2
votes
1answer
435 views

I want to understand Buildroot - the 3 compression config options (kernel, initramfs & rootfs)

I'm using buildroot to generate my images and for sure there is the option of compression with the help of different methods (LZO, LZMA, gzip, ...). So far i found these 3 compression options in ...
30
votes
4answers
19k views

How to XZ a directory with TAR using maximum compression?

So I need to compress a directory with max compression. How can I do it with xz? I mean I will need tar too because I can't compress a directory with only xz. Is there a oneliner to produce e.g. ...
3
votes
1answer
3k views

How to make nemo support compressing files by context menu?

I use Cinnamon on ArchLinux and Nemo is it's default file manager. I've tried 3 GUI file archivers (p7zip with WxGTK, peazip & file-roller), but none of them add a "compress option" in the context ...
1
vote
2answers
102 views

Debian: Create compressed Harddrive for copy

On my Debian system I have a box with certain configuration settings that I like but I've had to change them continuously. There have been times that I've gotten into a some-what irreversible ...
3
votes
1answer
93 views

What do you do to scan with 600 dpi while maintaing a small output file?

I just installed xsane which I already successfully tested with my Epson Perfection V30. When scanning with these settings the output file is remarkably large. Is there a way to decrease the size, ...
3
votes
1answer
339 views