Using OpenSSL hash to do file compare

Question

Not sure why this is failing..

./testme.sh
Before Loop
SSL1: /root/a.txt SHA256(/root/a.txt)= 92b165232fbd011da355eca0b033db22b934ba9af0145a437a832d27310b89f9
SSL2: /root/b.txt SHA256(/root/b.txt)= f0f9c277cf17429957daf6594714cc5470ac5c474ba5ac50319185477a174799
different


cp a.txt b.txt
./testme.sh
Before Loop
SSL1: /root/a.txt SHA256(/root/a.txt)= 92b165232fbd011da355eca0b033db22b934ba9af0145a437a832d27310b89f9
SSL2: /root/b.txt SHA256(/root/b.txt)= 92b165232fbd011da355eca0b033db22b934ba9af0145a437a832d27310b89f9
different

Checksums, and the same, but reported different :|

#!/bin/bash
#
# OPENSSL=/usr/bin/openssl
OPENSSL=/usr/local/openssl/bin/openssl
HOME=/root
ENCRYPT=sha256

SSL1=$($OPENSSL $ENCRYPT $HOME/a.txt)
SSL2=$($OPENSSL $ENCRYPT $HOME/b.txt)

## DEBUG
echo "SSL1: $HOME/a.txt $SSL1"
echo "SSL2: $HOME/b.txt $SSL2"


if [ "$SSL1" = "$SSL2" ]
 then
  echo "same"
 else
  echo "different"
fi

RK Dev · Accepted Answer · 2017-02-26 16:40:33Z

2

I was literally working on this today. Here's a one-liner tested on OSX

diff  <(openssl sha1 index.css | awk {'print $2'}) <(openssl sha1 original_source/index.css | awk {'print $2'})

No output on success; outputs both hashes on fail.

answered Feb 26, 2017 at 16:40

RK Dev

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Comments

ruakh · Accepted Answer · 2012-03-17 04:51:38Z

0

$SSL1 contains more than just the hash of the file; it also contains the string SHA256(/root/a.txt)=, which includes the filename. And likewise for $SSL2. So naturally they're not equal, since they contain different filenames.

To get just the hash, there are a few approaches you can take. I think the simplest is just to pipe it to grep:

SSL1=$($OPENSSL $ENCRYPT $HOME/a.txt | grep -o '[0-9a-f]*$')
SSL2=$($OPENSSL $ENCRYPT $HOME/b.txt | grep -o '[0-9a-f]*$')

answered Mar 17, 2012 at 4:51

ruakh

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2 Comments

Matt Smith Over a year ago

If I used sha256sum instead, would this need to change?

Matt Smith Over a year ago

Ah got it, sha256sum file | cut -d' ' -f1

Ignacio Vazquez-Abrams · Accepted Answer · 2012-03-17 04:50:16Z

0

Look closer. The result includes the filename.

answered Mar 17, 2012 at 4:50

Ignacio Vazquez-Abrams

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