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30
votes
1answer
1k 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 ...
0
votes
1answer
26 views

Syntax for compress utility [on hold]

I've been having some trouble deciphering the syntax from the man page, as well as other sources. I feel a bit stupid, as I've been studying Linux for a while now and this is the first thing I can't ...
6
votes
1answer
89 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 ...
14
votes
4answers
7k 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" ...
0
votes
1answer
1k 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', ...
8
votes
4answers
8k 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 ...
1
vote
1answer
1k 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 ...
5
votes
1answer
37 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
25 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 ...
4
votes
3answers
2k views

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

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 ...
1
vote
2answers
58 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
136 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), ...
1
vote
1answer
41 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
1answer
39 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
135 views

How to extract files from the 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
1answer
56 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 ...
19
votes
5answers
12k 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. ...
2
votes
1answer
1k 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
39 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
51 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
268 views
2
votes
1answer
149 views

Facility on AIX to ZIP a list of files

I'm working with an external company who is using AIX (version unknown) as their platform. They are required to FTP me a ZIP file containing multiple files. Does the UNIX utility zip exist on a ...
0
votes
1answer
890 views

Uncompress txt.gz files [closed]

Trying to uncompress txt.gz files on Linux. gzip, gunzip, unzip are not recognizing the file format. The archive is guaranteed to be not corrupted.
0
votes
2answers
83 views

File compression - how to implement in Linux

I would like to be able to compress certain files (that I need to keep, but use rarely) on disk. I noticed that chattr +c flags a file for compression, but it doesn't seem to actually compress files. ...
4
votes
1answer
2k views

What's the difference between gunzip and unzip?

What is the difference between gunzip and unzip? Tried to search but couldn't find anything relevant with this.
3
votes
3answers
335 views

Different count for compressed file listing vs directory listing

I was taking a backup of a folder, where I used the following command : sudo tar -zcvf www.tar.gz /var/www/ It successfully compressed, just for verifying the number of files in the compressed ...
1
vote
2answers
187 views

Having trouble uncompressing a few files [duplicate]

So I have to uncompress 4 different files. When I do file file1 file file2 file file3 file file4 for example, different messages are displayed. For example one starts like "gzip compressed data, ...
2
votes
1answer
114 views

Syslog TLS Compression and Message Buffering

Where I work, we have a site-to-site VPN tunnel set up between our main data center and a third party data center that does some Oracle PaaS for us. Since they charge per-VM, we're monitoring the ...
0
votes
1answer
121 views

How to compress wmv files on the linux console

I have some badly made WMV-files on my server that are huge (some GB) with just some picture slide-shows in it. Is it possible to compress them on the console there on the debian server so I can ...
1
vote
3answers
426 views

gzip, bzip2 and zip: very low compression ratio

I need to transfer (via ftp) some movie files (.MPG) on to remote machine. I thought to 1st compress it and then send. But all the compression utilities (gzip, bzip2 and zip) are having very less ...
3
votes
3answers
852 views

speed up gzip compression

Is it possible to speed up the gzip process? I'm using mysqldump "$database_name" | gzip > $BACKUP_DIR/$database_name.sql.gz to backup a database into a directory, $BACKUP_DIR. the manpage ...
4
votes
2answers
411 views

Best compression of similar files?

I've got a few full old backups of things like binary database dumps. Obviously, they don't differ much so doing full backups is not the smartest idea here. For now, I'm looking for a compression ...
2
votes
3answers
205 views

zcat a file line by line? [closed]

I have written a C++ application that reads files line by line. It reads one line, does processing, then reads the next line. I would like to add support for gzipped files, and am looking to an ...
2
votes
4answers
2k views

How to read a .war file?

I am trying to view the content of a .war file. I first did set its permissions with chmod 777 then when I try to accces it using: cd /usr/local/standalone/deployments/Sample.war/WEB-INF/classes/ ...
-1
votes
2answers
126 views

How to compress with bzip2 and gzip using xar?

In the "Why Xar" page of the Xar Google Code page it says: Additionally, this means xar can use different compression methods for each file in the archive. For instance, it might not be a good ...
13
votes
3answers
11k 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 ...
1
vote
0answers
44 views

problem with /compress

I have script that was provided with some SW. The script output is something like that (in debug mode). + changeDirectory + '[' -d /cdr/work/proc_raw/proc ']' + cd /cdr/work/proc_raw/proc + echo ...
-2
votes
1answer
105 views

file type determine [closed]

As part of the product, there were several scripts which was provided. In one of the scripts, I've found the following line which seems not to work properly find . -name *.old -type f -mtime +7 | ...
9
votes
3answers
681 views

Universal extractors

With an increasing number of archive/compression file formats, is there a single free/open-source command line tool to rule them all? Perhaps something with a consistent / unified set of flags? (note ...
3
votes
8answers
2k views

Triple compression and I only save 1% in space?

I've been trying to save space on my linux server, and I had a folder containting, in subfolders, 22GB of images. So I decided to compress them. First I used tar: tar -zcf folder.tar folder Then ...
1
vote
1answer
545 views

Difference between --xz and --lzma in GNU tar?

As far as I can tell, XZ is a container that uses the LZMA2 algorithm (i.e. extended LZMA); but e.g. $ xz foo/ complains about foo/ being a directory. So presumably the correct way to preserve ...
9
votes
2answers
2k views

How can I view gzipped files in less without having to type zless?

I am using Ubuntu, and I would like to be able to type less compressed_text_file.gz and page the contents of the text file in uncompressed form. Is there a way to do this?
2
votes
1answer
278 views

Will using a compressed filesystem over an encrypted volume improve performance?

Encryption/decryption is often the main bottleneck when accessing an encrypted volume. Would using a filesystem with a fast transparent compression (such as BTRFS + LZO) help? The idea is that there ...
0
votes
2answers
111 views

Can tar archiver zerofill a file?

I have received a tar archive from a co-worker and after decompresing I found that some text files are corrupted. More precisely they are filled with zeros. They have correct size but all bytes are ...
-1
votes
3answers
2k views

Determine whether a particular file is compressed

How to know in Linux whether a particular file is compressed or not using a command?
0
votes
2answers
277 views

Can I compress a compressed file more?

I have access to a server via SSH, I download files from it over SFTP or HTTP. I want to pull down a 4.4GB .mkv file but I have limited bandwidth. I have used zip, gzip and p7zip, but the file is ...
5
votes
1answer
814 views

On the Fly Compression for a Directory

I have a directory that is always going to be storing text files that are rarely (think weekly) used. Naturally this is a great place to use compression. However, rather than having to use tar ever ...
1
vote
0answers
46 views

Is it possible to get specific information about how a file is compressed?

File compression works on the basic idea of assigning commonly recurring chains of strings to a common index of a table where the full string is stored. For example: Input file: foo bar bash baz foo ...
0
votes
0answers
28 views

How to decompress content of various archive types with one command [duplicate]

Possible Duplicate: Is there any program to provide a consistent interface across multiple archive types? I have to handle files that come as uncompressed text files or in various archive ...
2
votes
1answer
63 views

Changing compression in memory

I have some large files that I need to change the compression type of for input to a program--I need to unrar them and then gzip (or bzip2) them. However, they're highly compressed files and I don't ...