How do I check the SHA1 hash of a file?

sha1sum

Print or check SHA1 (160-bit) checksums. With no FILE, or when FILE is -, read standard input.

sha1sum {file}

If you want to send the file together with its sha1sum output redirect the output to a file:

sha1sum {file} > {file}.sha1

Send both files and the other party can do a...

sha1sum -c {file}.sha1

It should show OK if the sha1 is correct.

Without creating local file:

$ sha1sum filename

8dd10000eb1b768800000e1d2fe1c3100005d2dc *filename

For checking, go to the directory that contains filename and run this command:

echo "8dd10000eb1b768800000e1d2fe1c3100005d2dc *filename" | sha1sum -c -

Its very simple.

Navigate to the terminal and key in:

sha1sum  filename

to check a sha1 hash use:

sha1sum -c filename.sha1

The check argument generates the sha1 hash of filename and compares it with the value stored in filename.sha1. If it matches OK is displayed and the exit code for the command is 0

For those who are on mac and don't have coreutils/sha1sum installed.

openssl sha1 <file>

Example:

$ openssl sha1 `mktemp`
SHA1(/tmp/tmp.jkyfOWma3t)= da39a3ee5e6b4b0d3255bfef95601890afd80709

What are you people talking about? Yes, I get the concept behind sha1sum, but the info above is confusing to say the best. First, Ubuntu does not seem to have sha1sum files - just strings on a web page such as this for Mate 16.04 Beta 1:

bfba577970d573e0ba5095fbb72787de97f88b4b *ubuntu-mate-16.04-beta1-desktop-amd64.iso
efcbbc70b10173cea203df30396d0848ba8fa0d8 *ubuntu-mate-16.04-beta1-desktop-i386.iso
8563fec4d66bce851b0800f5ac746f38e4041a6a *ubuntu-mate-16.04-beta1-desktop-powerpc.iso

To check the integrity of a downloaded .iso, one opens the terminal program, does "cd Downloads", then sha1sum <ubuntu-mate-16.04-beta1-desktop-i386.iso>. After a bit, the terminal will produce a hash such as

efcbbc70b10173cea203df30396d0848ba8fa0d8  ubuntu-mate-16.04-beta1-desktop-i386.iso

Next, we have to go to the web page and compare the strings to verify that the verification works. Not nearly as easy as it could be.

Python

Python has excellent hashlib library, that allows calculating multiple hashsums, including sha1. Here's a simple script that can do the job:

#!/usr/bin/env python3
import sys
import hashlib
import os
from collections import OrderedDict as od

def get_hashsums(file_path):
    hash_sums = od()
    hash_sums['md5sum'] = hashlib.md5()
    hash_sums['sha1sum'] = hashlib.sha1()
    hash_sums['sha224sum'] = hashlib.sha224()
    hash_sums['sha256sum'] = hashlib.sha256()
    hash_sums['sha384sum'] = hashlib.sha384()
    hash_sums['sha512sum'] = hashlib.sha512()

    with open(file_path, 'rb') as fd:
        data_chunk = fd.read(1024)
        while data_chunk:
              for hashsum in hash_sums.keys():
                  hash_sums[hashsum].update(data_chunk)
              data_chunk = fd.read(1024)

    results = od()
    for key,value in hash_sums.items():
         results[key] = value.hexdigest()         
    return results



def main():
    for path in sys.argv[1:]:
        print(">>> ",path)
        for key,value in get_hashsums(path).items():
            print(key,value)

if __name__ == '__main__': main()

Test run:

With a single file:

$ ./hash_sums.py /etc/passwd                                                                                                                         
>>>  /etc/passwd
md5sum ce5f247e016ba2bb92049fc86158376a
sha1sum b8abadf4618b09bd3eebb6064fc2df5b90e5ae03
sha224sum 044579d46e0d969a860602216ea4764465e5618ed714109cf782ff50
sha256sum 53f2ff8997625c958f77aef034f9c96d9fcfc8bcb4bb8a96fd8ac89a5ed5adf6
sha384sum b84b6cafa178147614e6b7903e1b7a342e09d95e3101e55c6a3b5b093a22190f2d367c69b1ee12b1ec59726337a40e9c
sha512sum edacca8237d3be5095f392c9d347dce3a5249c79d09f9b99a055b796edd74541b4529c499ff0e4f25e817b702c206073bfe5b0fccae6773680c79ea1e0efa9e2

With glob:

$ ./hash_sums.py *                                                                                                                                   
>>>  3-4-placement.py
md5sum a81dd2a6eb122176204cacd92d76d08c
sha1sum 4972f8cf08701cdfc6308def05d3ec2eedfcdd9a
sha224sum 32c4dad60f59584ba39ce73c1a1c96d4da36ee6fe3fd291145692b2b
sha256sum 7460ebf8736b0d6e7be8a1025743d0498871c7013cf5ad4463366fd95fe7576a
sha384sum 77de28b4b185d9a5d7d49aef0aad432d37145b914557dc6ecf3e6cdcbd6cd4a1999d717c027489ac99751f066050199b
sha512sum 7bf6a8059601c72e1278e321f225fef82f12a7bad73e1e8c5c43c1fcbdc2243934bf7d1ad07534bdbf10e2dd9ea9265e1debcbdf6603bec24ede665d2f651cf5
>>>  SHA256SUMS
md5sum 3c37318d45676c1db2598aa817b37679
sha1sum 8338b8ae5f749551d131dc28aebb80a2b125d651
sha224sum e89ad392f10a77b0940792a03470f3a23df2f2df9c8b6a91a1c496e0
sha256sum dd4a53f7da270f3b6ab691841ca911a231e20af53d7fabc5a39059b9dbdb036d
sha384sum aadfb55856730eb5b7e4192111bfb8fc4c022396a5809cb37fdd8e8b6ac8dbb3b7e462266cde2b34f90d7015fb42fe2b
sha512sum baba0ed86ad781daffb5905512459e353b7ca7da7b04cf67a26cfb320906041da2d4bc73673926aab7c98869f25bc2fd6ea0116c21c40c07188e6dcbbba3dbcf
>>>  answer.md
md5sum b6111facdba5978e6cf3a200706ba6fd
sha1sum 5c2eb00c4c0c4799d4457d3a84eea283a3a0d249
sha224sum 7172f877ab579e1ee845c723e0d42ff3acb96859cc43a56aebc39f59
sha256sum dc6ac7365f680e98b9f1279d2e22ed21b9b82c988b99b0facd5e8a98ff50ddd6
sha384sum 5082b3b62d677c5b1b8938f871da16c595be16a540bd76bc9c25ea6572dc9020f236237ec310cfa78fdaa1d0c0a51b0f
sha512sum 81f21316ab6c5a4038cdcde528766e620988a0ccf53bf2e9932399f4534c070468949a5a43ea68629c07e622404574e46bb20cf60c51da4e2a7a44a1df71d920