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65
votes
10answers
70k views

How do I get the MD5 sum of a directory's contents as one sum?

The md5sum program does not provide checksums for directories. I want to get a single MD5 checksum for the entire contents of a directory, including files in sub-directories. That is, one combined ...
20
votes
1answer
7k views

`mount -o loop` changes mounted ISO image file

It looks like mount -o loop changes the mounted image file. I downloaded the ISO image file and checked its SHA-1 checksum. Then I mounted that ISO file and the checksum changed. Here are the exact ...
19
votes
7answers
2k views

Why compute checksums of downloaded files?

I often see a checksum given next to a file available for download. The purpose of this practice eludes me. It is obviously to detect corrupt files, but what could be the cause of this corruption and ...
14
votes
1answer
6k views

Why does verifying SHA256 checksum with `sha256sum` fail on Debian and work on Ubuntu?

On Ubuntu 14.04, sha256sum from coreutils works as I expected: echo 879dd0d7637876be4796f7e6f194a111d21088be85cfe717fc97e2e7f05e79d2 /tmp/myfile | sha256sum -c /tmp/myfile: OK However, the exact ...
9
votes
5answers
521 views

find | xargs shasum creates checksum of checksum file itself (prematurely) and fails when checking

My problem (in a script with #!/bin/sh) is as follows: I try to checksum all files in a directory for archival purposes. The checksum (in my case sha1) file with all filenames should reside in the ...
9
votes
4answers
5k views

Is there MD5 (or similar) to a folder? How to verify if two folders are equal?

I'd like to find an md5sum (or similar calculation) of a folder without compressing it into an archive. For example, if in the folder MyFolder we have the files 1.txt, 2.txt and 3.txt, containing: ...
8
votes
5answers
3k views

Does gzip add integrity/crc check to a .tar?

I run commands: tar -cf myArchive.tar myDirectory/ gzip myArchive.tar then I copy the file over a lot of unreliable mediums, and later I unpack it using: tar -xzf myArchive.tar.gz The fact that ...
7
votes
1answer
6k views

Obtaining md5 during wget

I'm wget'ing huge files (over 100GB) and then comparing my md5sum to the sum posted in the repository. Believe it or not, md5sum takes a nontrivial amount of time to run on a file of this size, so ...
6
votes
3answers
26k views

How to check if a file is corrupt or not?

Are there any general solutions to check if a file is corrupt or not? For example, whether a video file is bad, or a compressed file is corrupt, etc.
6
votes
4answers
2k views

Ext4 - How to enable extra sanity, checksums, validations, tests of any kind?

I'm running Ext4 on a harddrive, and to be perfectly honest, I don't really trust the drive because it's old and has a few badblocks. I have nonessential data on the drive, so if it died tomorrow, ...
5
votes
5answers
3k views

How to check if the ISO was written to my USB stick without errors?

I followed these DebianEeePC HowTo InstallUsingStandardInstaller instructions at the Debian Wiki, to write a Debian ISO to my USB. dd if=debian-*-netinst.iso of=/dev/sdX Using sha1sum, I can check ...
5
votes
2answers
2k views

How to take sha-1, sha-256 or MD5 of CDs / DVDs?

I just tried burning both a Debian CD and a Debian DVD from their .iso files and I've got a weird behavior: the checksum of the CD is correct but the one of the DVD ain't. Here's what working: ...
5
votes
1answer
3k views

How unique are checksums?

I have a lot of files I need sorting; and sadly there are many files with the same name but different content, and there are the same content with different filenames. I'm thinking about using md5sum ...
5
votes
1answer
1k views

Appending checksum information to file

I'd like to embed checksum information into file, that I transfer. It's tar.gz or tar.xz file and I can only transfer one file to remote side. How do you recommend I embed checksum information? I ...
4
votes
2answers
2k views

How to verify Debian ISO integrity?

I recently downloaded Debian 7.5.0 Wheezy and managed to use the Release.sig signature to verify the integrity of the Release checksum file using GPG4Win. Unfortunately, I couldn't find any advice on ...
4
votes
1answer
72 views

Does rsync over any type of checksum? [duplicate]

I need to transfer files from several servers to a single remote host using Rsync over SSH. However, I need to be sure that before the file is deleted on the source using the --remove-from-source ...
3
votes
3answers
3k views

how to do checksum on a folder in Solaris

On my Solaris machine, I sometimes use the sum command to verify that a file has not changed. I now want to check whether a directory's contents have changed but sum only runs on files. Is there a ...
3
votes
2answers
4k views

How to create a md5-file for every folder in a drive recursivley?

I'm searching for a script which creates a md5 chechsum file for every single folder inside drive recursivley? I do have a copy of md5deep on my machine but I'm not that good in scripting bash.
3
votes
1answer
413 views

Generating/validating checksums in a single line?

When I generate checksums for my files, I have to do a bit of extra work to get them formatted properly: CHECKSUM="$(shasum "$file" | cut -b 1-40)" echo -n "$CHECKSUM" > "$file.sha" This is to ...
3
votes
1answer
907 views

FLAC correctness using MD5 placed in STREAMINFO

I know from [Sources], that FLAC computes CRC and MD5. What I am afraid that flac --test only does CRC test - as stated in man flac : same as -d except no decoded file is written . How to check flac ...
2
votes
3answers
295 views

Sanity checking MD5 sums

Do MD5 checksums contain a checkbit? I have to copy some MD5 checksums by hand (there's no other way) and was wondering whether there is any code out there that can validate a checksum as being valid ...
2
votes
3answers
70 views

Suppress filename from output of sha512sum

Maybe it is a trivial question, but in the man page I didn't find something useful. I am using Ubuntu and bash. The normal output for sha512sum testfile is <hash_code> testfile How to ...
2
votes
2answers
129 views

Diffference between Sha1sum, Sha256sum and Md5sum

What is the difference between Sha1sum, Sha256sum and Md5sum ? and how to check all these for some iso file? and how to create md5sum.txt file in ubuntu ?
2
votes
2answers
105 views

HDD cloning and non-matching checksums

I've been trying to clone a 1Tb HDD to a 1Tb SSD following the instructions here. I tried cloning it several times with both dd (painfully slow) and cat (far quicker) but when I came to do checksums ...
2
votes
1answer
76 views

What is a “checksum” and how do I use it from the shell?

I've seen on a lot of sites "checksum" hashes to verify the integrity of downloaded files. What are them and how do I use them? Ex: I have a downloaded-file.tar on the current working directory and ...
2
votes
1answer
850 views

alternative for digest -a sha256 command from solaris in linux

I have file from solaris which have digest -a sha256. But this command is not working in linux. I want the alternative for this command.
2
votes
1answer
1k views

Running sha1sum into several directories

I have several directories that share a common parent directory. In each directory there are regular files, but no other subdirectories. Something like this: top/dir-1 top/dir-1/file-11 ...
2
votes
3answers
45 views

Any good way to detect a misnamed config file?

I just solved an issue where my application was working on one computer, but I couldn't get it to work on a different computer. I spent several hours scratching my head, and finally figured out that I ...
2
votes
1answer
75 views

How to verify one file of a package, not the RPM itself

For instance, can I somehow use rpm to verify that /etc/pam.d/system-auth is unchanged since it was installed on the system? I know I can do this with an entire RPM, but I want to know if I can do ...
2
votes
1answer
269 views

Verifying Debian/Ubuntu packages integrity when booting from a read-only DVD?

Is there an easy way to boot a Debian-based Linux system from a read-only medium (say a Live Linux read-only DVD) and then use Debian's .deb checksums / signatures (?) to verify that the files ...
2
votes
1answer
2k views

Tar ignore or fix checksum

I have a archive backup.tar that was created with a nonstandard program a long time ago. I no longer have access to the original program. The archive is Not compressed (gzip). When trying to extract ...
2
votes
1answer
79 views

Generate SFV file, optimizing hard links

I'm currently running cfv -C -rr to generate a SFV file that contains the CRC32 checksums of all files in all subdirectories. The issue is that because there are so many hardlinks, this process is ...
2
votes
3answers
181 views

Repeatedly ziping a file that is newly created, but identical, however the shasum of the zip keeps changing

This is a followup to I am repeatedly zipping the same folder of files, but the shasum keeps changing essentially.. I am trying to add a file containing the git sha of the current commit when I zip a ...
2
votes
0answers
490 views

Software raid checksumming slow

On my new 24 disk array I get 900 MB/s of raw read or write using dd to all the disks. When I set the disks up as a 24 disk RAID6 I get 400 MB/s write and 600 MB/s read. It seems to be due to ...
1
vote
2answers
651 views

Is there file format for checksums?

I want to store SHA512 checksum of the file for my application. How to do it in common (popular) way? So this checksum can be used but by third party application too.
1
vote
3answers
37 views

Does it make sudo more secure when indexing all commands by their SHA-2 checksums?

I'm asking myself whether system security substantially increases when I generate a security policy, i.e. sudoers file which contains one or more Cmnd_Alias definitions that enumerate all executable ...
1
vote
3answers
738 views

Smarter filetransfers than rsync? [closed]

I have a large file (2-3 GB, binary, undocumented format) that I use on two different computers (normally I use it on a desktop system but when I travel I put it on my laptop). I use rsync to transfer ...
1
vote
1answer
325 views

Range of possible value returned by cksum

I am looking for the range of possible values that could be returned by cksum. E.g. echo -n '/my/path/filename' | cksum | cut -d' ' -f1 returns 2379496500. What is the range (min and max) of the ...
1
vote
3answers
184 views

Tool to remove all non-package files on a system

If you want to keep for example a build or server system clean, it is very useful to be able to check that all files are present and accounted for by the package metadata. At work we have a very nice ...
1
vote
1answer
107 views

Command to verify CRC (CRC32) hashes recursively

With the commands md5sum, sha1sum, sha256sum I can take a text file having an hash and a path per line and verify the entire list of files in a single command, like sha1sum -c mydir.txt. (Said text ...
1
vote
2answers
199 views

Difficulty using 'md5sum -c'

I'm having some difficulty using md5sum to verify some copied files. I have two directories: dir1 and dir2. In dir1 there are five files: file1, file2, file3, file4 and file5. dir2 is empty. If I ...
1
vote
1answer
65 views

I am repeatedly zipping the same folder of files, but the shasum keeps changing

I am zipping a folder and fingerprinting it with its shasum however this keeps changing on every zipping. Same with md5 any idea why? Is it working based on access time or something? Is there a way to ...
1
vote
1answer
41 views

Limiting readers on a pipe

I want to use a pipe to pass some security credential information from "process1" to another script. I only want authorized reader processes to be permitted to read the pipe. I am thinking I will ...
1
vote
1answer
53 views

validate all packages to be correct

I have two machines. One of which started to act strange lately (aptitude segfaulting, apt requiring a library named lkbm.qo.6). As the broken machine is not vital to me, I don't want to squash and ...
1
vote
1answer
80 views

checksum of corrupt file

A backup system ought to be able to handle several scenarios including file deletion, theft, natural disaster and file corruption. [http://en.wikipedia.org/wiki/Data_loss] In terms of file ...
1
vote
0answers
169 views

How to monitor the integrity of a script that is running?

I want to make sure a running python script was not modified accidentally by some other process (or cosmic ray, or unexpected developer update). I've heard of comparing a checksum of the script (e.g. ...
1
vote
2answers
1k views

md5 or sha1 while copying a file

Is there a way in any linux distro to perform a md5sum or sha1 check while the file is being transferred from a local partition to an NFS one? Example: I have a NFS mounted drive and a very big file ...
0
votes
2answers
1k views

different checksum of original file and copied file

I am running a script that copy a file from one location to other. In script I am calculating MD5sum using below command of original file and copied file and they are different: echo -n "file" | ...
0
votes
1answer
88 views

What changes my boot partition and how to prevent it?

As an another countermeasure against security threats I wrote a little script that computes MBR and boot checksum and then compare it to the old one. As long as the computer is running this is OK, but ...
0
votes
1answer
621 views

How do I put a checksum in a script?

I was (am) having trouble installing Eagle on my Linux (debian 8 jessie) computer. I was reading the installer script, when i noticed there is a checksum for the install script in the install script? ...