Questions tagged [checksum]

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4
votes
2answers
221 views

File Corruption between 2 HDD

I have a NAS running Ubuntu 16.04 LTS server i386 (kernel 4.4.211-0404211-generic). I use it with samba to share movies and music through my home network. I've tried to copy ~ 100 Go of data from an ...
2
votes
1answer
119 views

How to verify checksum file of centos 8?

How to verify that the CHECKSUM file for the CentOS 8 ISO is real? Download check sum and key: $ wget https://www.centos.org/keys/RPM-GPG-KEY-CentOS-Official $ wget http://www.gtlib.gatech.edu/pub/...
0
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0answers
30 views

Backups with checksums onto multiple drives

Is there a way to backup files onto multiple drives with checksums, which can be recovered without without manually having to see which files checksums are correct and copying the file from the drive ...
1
vote
2answers
55 views

unmount SD card makes file checksum change

I have an SD card mounted by Lubuntu at /media/$USERNAME/COREELEC/ I need to copy a file from one directory to another and rename it. However if I check the md5sum (or sha512sum) after I unmount it ...
2
votes
2answers
51 views

How to calculate n values in a column and the overall average?

I would really appreciate some help with this as I am relativity new to Linux. I'm using grep but I also want an average of all of my extracted values (irrespective of which column they are in) and ...
6
votes
1answer
129 views

Can files compressed with bzip2 be relied upon to be deterministic (reproducible)?

I am trying to determine if there are any potential issues using bzip2 to compress files that need to be 100% reproducible. Specifically: can metadata (name / inode, lastmod date, etc) or anything ...
4
votes
1answer
152 views

What checksum algorithm is used by Version 5 Unix?

I can't figure out, what algorithm was used in Unix V5 and V6 for the sum command. At first, I thought that it is a simple sum of bytes modulus 2^16. However for a string "1111111111\n" repeated 320 ...
1
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2answers
47 views

Keeping two offline data sets in sync

Suppose that we have two replicas A and B of a large data set in locations that don't have a good Internet connection. As a rule of thumb, let's say it's possible to transfer metadata but not actual ...
0
votes
1answer
489 views

How to disable TCP checksum validation on Linux?

For some reason, I want to disable TCP checksum validation on my Linux host. Is that possible to disable it?
-1
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1answer
106 views

do I use sha256sum or sha256hmac for file checksum

I have a text file with stuff in it I want to checksum it and create a hash for later use to know if the file has changed, when used anywhere else which to use? sha256sum myfile or sha256hmac myfile
0
votes
1answer
122 views

EXT4 CRC32C checksum algorithms are badly documented

So I'm making some kind of research on EXT4 checksums. I found this page and tried to calculate checksum by myself. I've started with Superblock since it is sounds pretty simple: "The entire ...
0
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0answers
53 views

Update an existing SFV file using CFV

I have an existing sfv file generated using cfv -C -tsfv -rr Now how would I update this file when there are new files added to the directory? Re-generating the whole thing will take a long time (an ...
0
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0answers
101 views

How are ext4fs checksums being calculated?

I've been studying ext4 file system contents and stumbled upon this paragraph: https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout#Checksums It says how blocks of data for different structures ...
1
vote
1answer
68 views

Can “parchive” be used for block devices?

As explained on wikipedia and Arch linux wiki "Parchive"s can be used to generate additional data for a file, that can be used in verification and even to some degree for repair/recovery of said file ...
1
vote
1answer
210 views

Use pv with find -exec

I use the following command to verify ~700 GiB of backed-up files: $ find -type f -exec md5sum {} + | sort > ~/checksums This takes many hours, so I would like to integrate pv into the command to ...
0
votes
3answers
1k views

Print SHA sums without “-” at the end?

Is it possible to have SHA sums print without the - appended to the end? $ echo test | sha1sum 4e1243bd22c66e76c2ba9eddc1f91394e57f9f83 - <--- this "-" dash/hyphen I know we can use awk and ...
2
votes
1answer
272 views

Is there a CLI utility to compute the same CRC as used in ZIP files?

# Create random file **$ dd if=/dev/urandom /of=./test.dat bs=1K count=1 # Zip it **$ zip test.zip test.dat # Dump contents for ZIP-computed CRC unzip -v test.zip Archive: test.zip Length ...
1
vote
1answer
581 views

What happened to elfsign and elfverify?

In "Uninformed Research -- informative information for the uninformed." 2003 mentions a tool called elfsign and elfverify. This is a tool to checksum and sign an ELF binary. I can't find that tool in ...
2
votes
1answer
396 views

Why does crc32 say some of my files are 'BAD'?

I used crc32 to compare some files with a backup of them. Out of 3556 files, 11 were reported as 'BAD' as in the following example: 9be46354 ./9836Feeding_the_dog_.mpeg BAD 9be46354 != ...
1
vote
3answers
69 views

Is it possible to search for a file using the checksum instead of the name? [duplicate]

Suppose I want to do a search to find out if I have a file that matches the sha256 generated from the file test1.txtusing the command: sha256sum -b test1.txt I get as output: ...
2
votes
4answers
4k views

How to verify a checksum using one command line?

Suppose I type and run the following command: sha256sum ubuntu-18.04.1-desktop-amd64.iso After a delay, this outputs the following: 5748706937539418ee5707bd538c4f5eabae485d17aa49fb13ce2c9b70532433 ...
1
vote
0answers
39 views

Is there a way to get package checksum using `zypper`?

How to get the checksum of the package when using zypper. I tried even the --xmlout option of zypper as zypper --xmlout --no-refresh install -D -y --no-recommends MozillaFirefox. Is there a way to ...
1
vote
1answer
585 views

Help with script/rsync command to move file with md5 sum comparison before deleting the source file/ [closed]

Referencing this post to find and delete duplicate files based on checksum, I would like to modify the approach to perform a copy operation followed by a file integrity check on the destination file. ...
1
vote
2answers
240 views

Fast way to get checksum for all files within a huge nested directory

We have a requirement to screen user-uploaded content. However, I've noticed that most of our user-uploaded content has actually originated from our own system: for example someone downloads a pdf ...
0
votes
1answer
494 views

md5sum warning about formatted lines

I am trying to validate a file using the following command: $ md5sum myfile_v2.1.ova -c myfile_v2.1.md5 md5sum: myfile_v2.1.ova: no properly formatted MD5 checksum lines found myfile_v2.1.ova: OK ...
3
votes
1answer
748 views

Easy backup solution to protect against bit rot (or verify)

I'm looking for an easy solution to protect against random bit flips (so-called bit rot) of data stored on various drives. They are not disk arrays, just single disks, that I backup once a week. So I'...
0
votes
0answers
213 views

compare checksum of files between two servers

I have to compare checksum of all files in /primary and /secondary folders in machineA with files in this folder /bat/snap/ which is in remote server machineB. The remote server will have lots of file ...
1
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1answer
2k views

compare checksum of files between two remote servers

On my local box "machineA", I have two folders "/primary" and "/secondary". These two folders have some files in it. Now on the remote server "machineB" I have one folder "/bat/snap/" which contains ...
1
vote
2answers
2k views

md5sum failed to open a file, directory issue

I'm having a problem checking certain .md5 files, they are all files that are in directories which have been renamed since the files were downloaded. [User1 Directory X]$ md5sum -c file1.txt.md5 ...
22
votes
2answers
2k views

md5sum prepends '\' to the checksum

Why md5sum is prepending "\" in front of the checksum when finding the checksum of a file with "\" in the name? $ md5sum /tmp/test\\test \d41d8cd98f00b204e9800998ecf8427e /tmp/test\\test The same ...
3
votes
0answers
376 views

Do rsync --checksum and diff usually have different outputs or is my hdd broken?

I set up a NanoPi Neo 2 with OpenMediaVault (Debian Jessie) as its OS and have an hdd attached to it (the OS is on an SD card). When I now copy my data from my external hard drive onto my system with ...
2
votes
2answers
675 views

csum errors on btrfs containing virtual disk

I have a btrfs disk that suffered some damage from hardware failure and spits i/o errors when copying certain files. I ran btrfs scrub, and when it reported csum errors I offlined it and did a btrfs ...
0
votes
1answer
759 views

How to verify file/directory integrity when using SCP over SSH?

I just copied a few directories and files using SCP from a SSH remote server. How can I check if the files were copied exactly and there were no errors or no files were skipped?
1
vote
2answers
1k views

How to separately checksum each “block” of a large file

I am storing some multi-GB files on two hard drives. After several years in offline storage (unfortunately in far from ideal conditions), I often get some files with bit-rot (the two copies differ), ...
3
votes
2answers
3k views

How to checksum a CD/DVD? (to verify integrity of my Debian installation)

So I'd like to checksum my Debian 9.0 installation DVD to be able to compare it to the respective .iso file's hashes and the published hashes to be able to verify my installation's integrity. I ...
1
vote
1answer
529 views

Creating a checksum of a 7zip archive being created from a tar file being created

I want to solve a problem (which you can read about here as I don't feel like this should be part of the question). So this is what I came up with: $ tar -cO Templates | 7z a -si -mx=3 -p /t/out.tar....
0
votes
1answer
932 views

Trouble verifying download of openSUSE Tumbleweed image

When I try using sha256sum to verify the openSUSE Tumbleweed image I just downloaded, I get an error: sha256sum: openSUSE-Tumbleweed-DVD-x86_64-Snapshot20170521-Media.iso: No such file or directory ...
-2
votes
1answer
513 views

apt-fast checksum error detected on kali linux [closed]

I installed apt-fast to fasten the download process of apt-get but when i try to upgrade an application apt-fast don't download the .deb files instead it reports an error saying there is a checksum ...
0
votes
2answers
1k views

Kali Linux upgrade fails on Metasploit with hash checksum error

I have just created a fresh boot of Kali Linux in order to begin learning penetration testing and security vulnerabilities so hopefully I can find a few 0days, then sell information on them to ...
19
votes
7answers
7k views

How can I generate SHA3 if there is no sha3sum command in coreutils?

I have sha1sum or sha512sum on an average Linux distro. But where is the sha3sum command that can generateSHA-3 commands?
1
vote
1answer
157 views

Does the 'genisoimage' command checksum the generated image against the source folder?

When generating an ISO image using the genisoimage command (apparently "a carbon copy of mkisofs"): genisoimage -o image.iso path/to/source/directory Is a checksum or other type of verification ...
0
votes
1answer
1k views

Issues installing CUDA 8.0 on Debian 8 possibly checksum issue

So I was following the answered instructions here, How to install CUDA Toolkit 7.x or 8 on Debian 8 (Jessie) or 9 (Stretch)? and I get the following error when I run the .run file: gzip: stdin: ...
3
votes
1answer
518 views

Why would `cksum` be running slower than `md5sum`?

I've been backing up Windows installer images for my virtual machine, and to verify the data was transferred correctly, I've been using cksum. Out of curiosity, I decided to compare the times it took ...
7
votes
2answers
3k views

Understanding the error reporting of ZFS (on Linux)

I have successfully setup Debian stretch on ZFS, including the root file system. Things are working like expected, and I was thinking that I had understood the basic concepts - until I re-read Sun's ...
1
vote
1answer
436 views

Diffing two directories recursively based on checksums?

I'm trying to find what files don't exist by a checksum of their content. I have two directories /foo and /bar, both of these directories represent arbitrary states on the system, I want to find all ...
6
votes
4answers
680 views

Rename files based on checksum

I have a md5sum list and a lot of file which I wanted to checksum and then rename them according to the md5sum list. Example of the list: d4cd401ade018617629b39efed7b7be4 foo.bar ...
11
votes
2answers
684 views

FreeBSD package repo - how to do manual signature verification?

I'm trying to verify a signature of a package on the FreeBSD package website wget http://pkg.freebsd.org/FreeBSD:11:amd64/latest/digests.txz tar xf digests.txz This gives three files: digests, ...
0
votes
1answer
1k views

Can tar verify integrity of untarred files on destination disk?

Example: I create a.tar.gz from the file "a.txt" (so I used the -z option). Let's say the checksum of the file a.txt before it's added to the archive is "abc123". When I untar and "a.txt" is written ...
1
vote
2answers
339 views

Deduplicate image files

[user@notebook foobar]$ ls *.jpg|wc -l 1959 [user@notebook foobar]$ cksum * | cut -d' ' -f-2 | sort | uniq -di | wc -l 698 [user@notebook foobar]$ There are many jpg files in a directory. Many of ...
3
votes
2answers
5k views

Most practical way to compare md5 checksums

It seems to me that .md5 checksum files provided for verifying downloads mostly contain the checksum for the file to verify, but not the filename. Using md5sum that's seemingly a bit impractical, ...