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Chapter 1C. Manual Download and Verification of Debian on Ubuntu.

1. First, open up a terminal shell.  Click on the Ubuntu Dash button in the top left corner of your 

dock bar.  Then, type “terminal” and click on the Terminal icon.

Chapter 1C. Manual Download and Verification of Debian on Ubuntu.
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2. When the terminal opens, import the Debian CD signing key.  Type “gpg --keyserver 

hkp://hkps.pool.sks-keyservers.net --recv-keys 
DF9B9C49EAA9298432589D76DA87E80D6294BE9B
”.

If the key import was successful, your output will look like the output pictured below.

3. Next, verify the fingerprint of the Debian CD signing key. Type “gpg --fingerprint 

DF9B9C49EAA9298432589D76DA87E80D6294BE9B”

Your output should mirror what is pictured below.  If it does not, start over from step 2.

Chapter 1C. Manual Download and Verification of Debian on Ubuntu.
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4. Next, download the Debian Installation ISO image.

If you have a 32 bit processor, or 4 gigs of RAM or less, type  “wget -c 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/i386/iso-cd/debian-8.7.0-i386-
netinst.iso
” press enter. 

If you have a 64 bit processor, type “wget -c 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/amd64/iso-cd/debian-8.7.0-
amd64-netinst.iso
” and press “enter.”

5. Now, download the has checksum file for verifying that the Debian Installation ISO image you 

downloaded has not been tampered with or corrupted. 

If you have downloaded the version for a 32 bit processor, type “wget 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/i386/iso-cd/SHA512SUMS
” and 
press “enter.”

If you downloaded the version for a 64 bit processor, type “wget 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/amd64/iso-cd/SHA512SUMS
” 
and press “enter.”

Chapter 1C. Manual Download and Verification of Debian on Ubuntu.
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6. Next, download the GPG signature to verify that the Debian checksums haven't been tampered 

with.  

If you selected the 32 bit processor related checksums file in the last step, type “wget 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/i386/iso-cd/SHA512SUMS.sign
” 
and press “enter.”

If you selected the 64 bit related checksums file in the last step, type “wget 
https://cdimage.debian.org/mirror/cdimage/archive/8.7.0/amd64/iso-
cd/SHA512SUMS.sign
” and press “enter.”

7. Next, verify the hash checksum file that will be used to verify the Debian ISO image. Type 

gpg -v SHA512SUMS.sign” and press “enter.”

The output from the command above should look like the screenshot below with a “good 
signature.” However, if the output states “bad signature,” your download or keyfiles have been 
corrupted or tampered with.  If you get a “bad” result, restart from step 5. 

NOTE: You can ignore the “warning” that the “key is not certified.” This is not relevant in the 
context.

Chapter 1C. Manual Download and Verification of Debian on Ubuntu.
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8. Next, verify that the Debian ISO image is not corrupt and has not been tampered with. Type 

cat SHA512SUMS |grep netinst |sha512sum -c -”.

Note: The symbol in the line to type above that looks like a vertical line is the “pipe” character. 
On your keyboard, it often looks like a vertical line and is is accessed by holding the “shift” key
and pressing the “\” key often located above the “enter” key. 

You should get a result saying the file is “OK” like the screen shot below.  If it says otherwise, 
your Debian ISO image has either been tampered with or is corrupt. If your Debian ISO image 
does not pass this check, download Debian again as described in Step 4. 

NOTE: If you plan on burning the Debian Installation ISO image to a CD/DVD, do so now and
continue from Chapter 1D.  The remaining steps are only applicable if you wish to use a 
bootable USB drive for the Debian Installation ISO.

9. Next, type “df -h” and press “enter.” Note the output of your screen. It will look similar to the 

screen shot below.

Chapter 1C. Manual Download and Verification of Debian on Ubuntu.
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10. Now, plug in the USB drive you wish to use as your installation disk and click on the new disk 

icon that appears in your application launcher if the disk does not automatically open.  Then, to 
determine the device name of your USB drive, type “df -h” in the terminal and press “enter” 
again.  Your USB drive will now display as the one you did not see in the step before. It will 
likely appear as “/dev/sdb1.”  However, this may differ based on your system configuration. 
Make a note of this information.

11. Next, unmount your USB drive. Type “sudo umount /dev/sdX1” and press “enter.” You will 

likely be prompted for your password. 

NOTE: “/dev/sdX1” represents the name of the device you took note of in the previous step.  In
the image below, “/dev/sdb1” represents the USB disk.  Thus, replace '/dev/sdX1” with the 
name of the device you noted in the previous step.

Chapter 1C. Manual Download and Verification of Debian on Ubuntu.
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12. Now, install the Debian install disk on your USB drive. NOTE: THIS STEP WILL ERASE 

ALL CONTENTS ON THE TARGET DRIVE SPECIFIED! IF YOU HAVE 
IMPORTANT DATA ON YOUR USB DRIVE, BACK IT UP BEFORE CONTINUING. 
ADDITIONALLY, MAKE SURE YOU SELECT YOUR USB DRIVE!

If you downloaded the 32 bit version of Debian, type “for f in debian-*-netinst.iso; do sudo 
dd if=$f of=/dev/sdX bs=4M; sync; done
” and press enter.  

NOTE: “/dev/sdX” represents the name of the device you took note of in the previous step.  In 
the image below, “/dev/sdb” represents the USB disk.  Thus, replace '/dev/sdX” with the name 
of the device you noted in the previous step. Do not include the number after the device name in
this step. In should be “/dev/sdX” and not “/dev/sdX1.”

13. When the process above finishes, you will be returned to a command prompt. Restart your 

computer and 

continue from Chapter 1D.