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Questions tagged [checksum]

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0
votes
1answer
39 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
26 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
28 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
10 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
43 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
21 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
49 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
2answers
175 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 ...
3
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1answer
42 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
177 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
110 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
59 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: ...
1
vote
2answers
1k 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
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0answers
30 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
266 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
181 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
168 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 ...
2
votes
1answer
405 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
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0answers
84 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
1k 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
851 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
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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
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0answers
317 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
427 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
497 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
703 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), ...
2
votes
2answers
2k 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
300 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
667 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
468 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
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2answers
839 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 ...
15
votes
6answers
4k 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
126 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
776 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
325 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 ...
5
votes
2answers
2k 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
197 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
481 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 ...
8
votes
1answer
531 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
400 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
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2answers
286 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
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2answers
3k 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, ...
3
votes
1answer
403 views

various checksums utilities precede hash with backslash

What is going on here? A backslash in a directory name and/or file name seems to cause various checksum utilities to report the hash preceded with a backslash slash. Note that the coreutil wc does ...
6
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2answers
4k views

Verifying a large directory after copy from one hard drive to another

I have a home file server that I use Ubuntu on. Recently, one of my drives filled up so I got another and threw it in there. I have a very large folder, the directory is about 1.7 T in size and ...
0
votes
1answer
278 views

Way to eliminate external commands from scriptfor generating NMEA 0183 xor checksum using bash [closed]

I recently had the need to generate and verify NMEA 0183 checksums using bash and I couldn't find much written to accomplish exactly what I needed. NMEA 0183 sentences start with a $ and end with a *...
-2
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1answer
215 views

Where is the GNU checksum file format defined?

Where is the GNU checksum file format defined? I don't see any mention of the checksum file format at the GNU documentation website
3
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2answers
478 views

How to create sha1 checksums of files inside a tar archive on busybox without using much disk space

I would like to get the sha1 checksums of all files inside a simple tar archive as a list. This should be done on a busybox machine where only a minimal tar binary is avalable, see http://linux.die....
5
votes
1answer
250 views

Is it possible to explicitly retrieve full file contents with bad checksum on a btrfs filesystem?

Imagine a situation when a file became corrupted on a single device Btrfs. And in this case file contents are needed as is including corrupted bits. As stated in man page for mount: nodatasum ...
1
vote
1answer
332 views

Does data checksumming remain for files with No_COW file attribute on Btrfs filesystem?

Assume that we don't invoke additional mount options like nodatacow and nodatasum. Operate only at file attributes level, which are controlled with lsattr/chattr. Does setting No_COW on a file (...
1
vote
1answer
333 views

Using crc32 to find if files were harmed or damaged

I have a directory with a content. To ensure nothing will get lost with copying I compressed the directory and now I have a dir.tar.gz file. The copying still troubles me and the files are damaged so ...