how do I verify that the the checksum is correct?

[Alex Miua]

Hi there!

When I do : -

sha1sum <iso file>

this will output the checksum , do I have to verify by
looking at the huge number that it is correct or is
there a simple utilty which can compare the 2
checksums  ?

Thank you,
Alex.


 
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[Frank Cox]

On Fri, 02 Feb 2007 08:27:45 -0800 (PST)
Alex Miua <amateur_radio_2007(a)yahoo.com&gt; wrote:

>  When I do : sha1sum <iso file>  this will output the checksum ,
> do I have to verify by
>  looking at the huge number that it is correct or is  there a simple utilty which can
> compare the 2
>  checksums  ? 
sha1sum -c sha1sumfile.txt

-- 
MELVILLE THEATRE ~ Melville Sask ~ http://www.melvilletheatre.com

[Alex Miua]

Thank you for your reply. so this needs to be done 
after all iso's are downloaded ? 


--- Frank Cox <theatre(a)sasktel.net&gt; wrote:

>  On Fri, 02 Feb 2007 08:27:45 -0800 (PST)
>  Alex Miua <amateur_radio_2007(a)yahoo.com&gt; wrote:
>  
>  > When I do : sha1sum <iso file>  this will output
>  the checksum , do I have to verify by
>  > looking at the huge number that it is correct or
>  is  there a simple utilty which can compare the 2
>  > checksums  ?
>  
>  sha1sum -c sha1sumfile.txt
>  
>  -- 
>  MELVILLE THEATRE ~ Melville Sask ~
>  http://www.melvilletheatre.com
>   



 
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[Rick Stevens]

On Fri, 2007-02-02 at 08:27 -0800, Alex Miua wrote:
>  Hi there!
>  
>  When I do : -
>  
>  sha1sum <iso file>
>  
>  this will output the checksum , do I have to verify by
>  looking at the huge number that it is correct or is
>  there a simple utilty which can compare the 2
>  checksums  ? 
Grab the SHA1SUM file from the repository you're downloading from, then
"cd" to the directory with the SHA1SUM file and the ISOs and run
"sha1sum -c SHA1SUM".

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[Howard Howell]

On Fri, 2007-02-02 at 08:27 -0800, Alex Miua wrote:
>  Hi there!
>  
>  When I do : -
>  
>  sha1sum <iso file>
>  
>  this will output the checksum , do I have to verify by
>  looking at the huge number that it is correct or is
>  there a simple utilty which can compare the 2
>  checksums  ?
>  
>  Thank you,
>  Alex. 
My trick is to copy the checksums into a text file, highlight one of
them and use find to see if it finds the next one.

Regards,
Les H

[Paul Smith]

On 2/2/07, Les <hlhowell(a)pacbell.net&gt; wrote:
>  > When I do : -
>  >
>  > sha1sum <iso file>
>  >
>  > this will output the checksum , do I have to verify by
>  > looking at the huge number that it is correct or is
>  > there a simple utilty which can compare the 2
>  > checksums  ?
>  >
>  > Thank you,
>  > Alex.
>  My trick is to copy the checksums into a text file, highlight one of
>  them and use find to see if it finds the next one. 
I have written a tiny script to do that. Basically, it compares two
strings. I will post it to you later on, as I have not it with me now.

Paul

[Paul Smith]

On 2/2/07, Paul Smith <phhs80(a)gmail.com&gt; wrote:
>  > > When I do : -
>  > >
>  > > sha1sum <iso file>
>  > >
>  > > this will output the checksum , do I have to verify by
>  > > looking at the huge number that it is correct or is
>  > > there a simple utilty which can compare the 2
>  > > checksums  ?
>  > >
>  > > Thank you,
>  > > Alex.
>  > My trick is to copy the checksums into a text file, highlight one of
>  > them and use find to see if it finds the next one.
>
>  I have written a tiny script to do that. Basically, it compares two
>  strings. I will post it to you later on, as I have not it with me now. 
My simple script has the following code:

#!/bin/sh

if [ "$1" = "$2" ] ; then echo "same" ; else echo
"different" ; fi

Paul

[Alex Miua]

Ahh I thought along similar lines. In fact DOS has a
file comparing utility ? filecompare ? I guess that
can be used if one has windows and is installing FC.

Anyone remembers the exact name of that DOS utility?

Thank you.

--- Paul Smith <phhs80(a)gmail.com&gt; wrote:

>  On 2/2/07, Paul Smith <phhs80(a)gmail.com&gt; wrote:
>  > > > When I do : -
>  > > >
>  > > > sha1sum <iso file>
>  > > >
>  > > > this will output the checksum , do I have to
>  verify by
>  > > > looking at the huge number that it is correct
>  or is
>  > > > there a simple utilty which can compare the 2
>  > > > checksums  ?
>  > > >
>  > > > Thank you,
>  > > > Alex.
>  > > My trick is to copy the checksums into a text
>  file, highlight one of
>  > > them and use find to see if it finds the next
>  one.
>  >
>  > I have written a tiny script to do that.
>  Basically, it compares two
>  > strings. I will post it to you later on, as I have
>  not it with me now.
>  
>  My simple script has the following code:
>  
>  #!/bin/sh
>  
>  if [ "$1" = "$2" ] ; then echo "same" ; else echo
>  "different" ; fi
>  
>  Paul
>  
>  -- 
>  fedora-list mailing list
>  fedora-list(a)redhat.com
>  To unsubscribe:
>  https://www.redhat.com/mailman/listinfo/fedora-list
>   


 
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[Jacques B.]

The -c option is the easiest in my opinion as it uses the features of
the checksum application.

If you want to do it otherwise, you could do something like:

test [ "`sha1sum cd.iso`" = "`cat checksumfile.txt`" ] &&
echo
"matches" || "echo "no match"
where checksumfile.txt is the one provided by the web site.

I'm not in my Linux partition right now so I can't check the syntax to
be exactly certain that is right.  If it's off I'm sure someone can
correct it.  But ultimately why do that when you can simply use the -c
option?

Alternatively you could do
sha1sum cd.iso >> checksumfile.txt
where "checksumfile.txt" is the one provided by the web site.
Then you can cat the file and easily compare the two because they will
be one under the other so at a glance easy to see if they match or
not.

Jacques B.

[Alex Miua]

Thank you for your reply. Will do.

Alex.
--- "Jacques B." <jjrboucher(a)gmail.com&gt; wrote:

>  The -c option is the easiest in my opinion as it
>  uses the features of
>  the checksum application.
>  
>  If you want to do it otherwise, you could do
>  something like:
>  
>  test [ "`sha1sum cd.iso`" = "`cat checksumfile.txt`"
>  ] && echo
>  "matches" || "echo "no match"
>  where checksumfile.txt is the one provided by the
>  web site.
>  
>  I'm not in my Linux partition right now so I can't
>  check the syntax to
>  be exactly certain that is right.  If it's off I'm
>  sure someone can
>  correct it.  But ultimately why do that when you can
>  simply use the -c
>  option?
>  
>  Alternatively you could do
>  sha1sum cd.iso >> checksumfile.txt
>  where "checksumfile.txt" is the one provided by the
>  web site.
>  Then you can cat the file and easily compare the two
>  because they will
>  be one under the other so at a glance easy to see if
>  they match or
>  not.
>  
>  Jacques B.
>  
>  -- 
>  fedora-list mailing list
>  fedora-list(a)redhat.com
>  To unsubscribe:
>  https://www.redhat.com/mailman/listinfo/fedora-list
>   


 
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[Jacques B.]

>  test [ "`sha1sum cd.iso`" = "`cat
> checksumfile.txt`" ] && echo
>  "matches" || "echo "no match"
>  where checksumfile.txt is the one provided by the web site. 
Minor correction to the above.  I booted to my FC partition and tested
it outside and within a script.  The proper syntax is:

test "$(sha1sum cd.iso)" = "$(cat checksumfile.txt)" && echo
"Matches"
|| echo "No match"
or
test "`sha1sum cd.iso`" = "`cat checksumfile.txt`" && echo
"Matches"
|| echo "No match"

The difference being no square brackets [].  Of the two syntaxes
above, I've been typically using the back ticks ` (above the tidle ~).
 But in a BASH scripting book that I have the author uses $() instead
of ``.

If you have several iso files that youve downloaded along with their
checksum files, simply cat all the files into one
cat cd1chksum.txt cd2chksum.txt cd3chksum.txt etc... > checkthese.txt
and then run the command
sha1sum -c checkthese.txt

A quick and efficient way to check several checksum files.

Jacques B.