Need help with bash (Beginner)

suicidaleggroll · 03-02-2016, 04:15 PM

Quote:

Originally Posted by Pandapoke

Now i get the error message "dd: failed to open ‘~/Downloads/OS/Linux/Dists/mint173c.iso’: No such file or directory
0B 0:00:00 [ 0B/s] [<=> " but it is the right location.

That's because you're running sudo. Sudo switches to root, and once you're running as root, "~" points to /root/ instead of /home/user/. If you use $HOME instead, it will be expanded when calling the script and should work.

brokenleg · 03-02-2016, 04:34 PM

Make sure the endline format is unix and not windows.

pan64 · 03-03-2016, 12:42 AM

you can try to use dcfldd instead of dd, that will make your script better (pv is built-in)

Pandapoke · 03-03-2016, 03:33 AM

Were i the code should i put

Quote:

echo "Going to format $device, are you sure (y/N)?"
read ans
if [[ "$ans" != "y" && "$ans" != "Y" ]]; then
echo "Exiting on user cancel"
exit 3
fi

size=$(fdisk -l $device | grep bytes | head -n 1 | awk '{print $5}')
sizeGB=$(echo "$size / 1073741824" | bc -l | xargs printf "%7.2f\n")
echo "Detected a $sizeGB GB device at $device, is this correct (y/N)?"
read ans
if [[ "$ans" != "y" && "$ans" != "Y" ]]; then
echo "Exiting on user cancel"
exit 3
fi

And dont i need bs in the dd command?

Quote:

4) sudo dd if=$iso of=/dev/$device
echo "Burn done"
exit ;;

mvh

pan64 · 03-03-2016, 03:36 AM

$sizeGB is incorrect, you do not have variable named sizeGB defined. Use ${size}GB instead
Otherwise I do not really understand what is your current problem

Pandapoke · 03-03-2016, 03:48 AM

Thanks for all the help

where should i put this code in mine?

Code:

echo "Going to format $device, are you sure (y/N)?"
read ans
if [[ "$ans" != "y" && "$ans" != "Y" ]]; then
   echo "Exiting on user cancel"
   exit 3
fi

size=$(fdisk -l $device | grep bytes | head -n 1 | awk '{print $5}')
sizeGB=$(echo "$size / 1073741824" | bc -l | xargs printf "%7.2f\n")
echo "Detected a $sizeGB GB device at $device, is this correct (y/N)?"
read ans
if [[ "$ans" != "y" && "$ans" != "Y" ]]; then
   echo "Exiting on user cancel"
   exit 3
fi

And does not dd need bs command?

Quote:

Originally Posted by michaelk

Code:

sudo "dd if=$iso | pv | of=/dev/$device bs=$speed"

Your mixing commands.

Go back to your original code then add the fancy stuff. Try this:

Code:

4) sudo dd if=$iso of=/dev/$device 
   echo "Burn done" 
   exit ;;

thanks
mvh

pan64 · 03-03-2016, 03:52 AM

"dd if=$iso | pv | of=/dev/$device bs=$speed" is syntactically incorrect. It looks like 3 commands:

Code:

dd if=$iso
pv
of=/dev/$device bs=$speed

chained together with pipes, but of=/dev/$device bs=$speed is not a valid command but the second half of the first one (dd).
You need to understand it is simply wrong, useless.

michaelk · 03-03-2016, 06:33 AM

Code:

4) echo "Going to format $device, are you sure (y/N)?"
read ans
if [[ "$ans" != "y" && "$ans" != "Y" ]]; then
   echo "Exiting on user cancel"
   exit 3
fi
...

The default block size is 512 bytes which is typically the default for flash drives. So bs isn't absolutely necessary. You also want to make sure to unmount the device if mounted.

suicidaleggroll · 03-03-2016, 08:02 AM

Quote:

Originally Posted by Pandapoke

Thanks for all the help

where should i put this code in mine?

Code:

echo "Going to format $device, are you sure (y/N)?"
read ans
if [[ "$ans" != "y" && "$ans" != "Y" ]]; then
   echo "Exiting on user cancel"
   exit 3
fi

size=$(fdisk -l $device | grep bytes | head -n 1 | awk '{print $5}')
sizeGB=$(echo "$size / 1073741824" | bc -l | xargs printf "%7.2f\n")
echo "Detected a $sizeGB GB device at $device, is this correct (y/N)?"
read ans
if [[ "$ans" != "y" && "$ans" != "Y" ]]; then
   echo "Exiting on user cancel"
   exit 3
fi

And does not dd need bs command?

thanks
mvh

No, the bs flag just changes the default from 512 bytes.

As for where to put the confirmation questions, that should be obvious...somewhere between when the user enters the device name and where you blow it away with dd.

Honestly, this thread has done nothing but made it ABUNDANTLY clear you are not ready to dd inside a script. Put this on the back burner until you gain more scripting experience, I'm serious. You're not ready to automate any command that requires sudo, most certainly not dd. It's not meant as an insult, I'm just trying to keep you from destroying your system. dd doesn't have the nickname "disk destroyer" for nothing.

Pandapoke · 03-03-2016, 02:56 PM

I have most of the code figured out execpt the dd command itself

Code:

#!/bin/bash
#set -vx
speed=512K
while true
do

    clear
    echo "============================="
    echo "    Burning menu using dd    "
    echo "============================="
    echo "Enter 1 for full path to iso."
    echo "Enter 2 for media"
    echo "Enter 3 to set bs speed 512K default"
    echo "Enter 4 to execite dd command "
    echo "Enter q to exit q:"
    echo -e "\n"
    echo -e "Enter your choice \c"
    read -r choice
    case "$choice" in
        q) exit ;;
        1) echo -e "Enter path to iso \c"
           read -r iso ;;
        2) echo -e "Enter device"
           read -r device ;;
        3) echo -e "Enter bs speed \c"
           read -r speed ;;
        4) echo "Going to format $device, are you sure (y/N)?"
           read ans
        if [[ "&ans" != "y" && "&ans" != "Y" ]]; then
            echo "Clearing screen"
            sleep 3
            clear
            "dd if=$iso of=/dev/$device bs=$speed"
            echo "Burning please wait"
            sleep 30
        fi
    esac
done

but when i execture "4" to use dd command i get this output

Quote:

./burn2.sh: line 33: dd if=~/Downloads/OS/Linux/Dists/m.img of=/dev/sdb1 bs=512K: No such file or directory

There is such a file and i have tried with other iso:s and img:s

can anyone help a beginner?
mvh

Thanks in advance.

rtmistler · 03-03-2016, 03:10 PM

Quote:

Originally Posted by Pandapoke

I have most of the code figured out execpt the dd command itself

Code:

#!/bin/bash
#set -vx
speed=512K
while true
do

    clear
    echo "============================="
    echo "    Burning menu using dd    "
    echo "============================="
    echo "Enter 1 for full path to iso."
    echo "Enter 2 for media"
    echo "Enter 3 to set bs speed 512K default"
    echo "Enter 4 to execite dd command "
    echo "Enter q to exit q:"
    echo -e "\n"
    echo -e "Enter your choice \c"
    read -r choice
    case "$choice" in
        q) exit ;;
        1) echo -e "Enter path to iso \c"
           read -r iso ;;
        2) echo -e "Enter device"
           read -r device ;;
        3) echo -e "Enter bs speed \c"
           read -r speed ;;
        4) echo "Going to format $device, are you sure (y/N)?"
           read ans
        if [[ "&ans" != "y" && "&ans" != "Y" ]]; then
            echo "Clearing screen"
            sleep 3
            clear
            "dd if=$iso of=/dev/$device bs=$speed"
            echo "Burning please wait"
            sleep 30
        fi
    esac
done

but when i execture "4" to use dd command i get this output

There is such a file and i have tried with other iso:s and img:s

can anyone help a beginner?
mvh

Thanks in advance.

I think you've been told a few times that you need to use sudo for the dd command. Or be root. In addition to that, you also should not use $HOME or the ~ notation because it will point to /home/root, instead you should save the full path into another variable, such as START_DIR=/home/wherever/Downloads/etc/etc and then use that variable $START_DIR.

suicidaleggroll · 03-03-2016, 04:08 PM

Quote:

Originally Posted by rtmistler

I think you've been told a few times that you need to use sudo for the dd command. Or be root. In addition to that, you also should not use $HOME or the ~ notation because it will point to /home/root, instead you should save the full path into another variable, such as START_DIR=/home/wherever/Downloads/etc/etc and then use that variable $START_DIR.

$HOME should be fine, because the variable substitution will occur before sudo gets a hold of the argument.

rtmistler · 03-03-2016, 04:19 PM

Quote:

Originally Posted by suicidaleggroll

$HOME should be fine, because the variable substitution will occur before sudo gets a hold of the argument.

I concede that point. I personally prefer to be exact. Then again I also suggested not "firing away" with a command like dd and instead outputting a summary and allow the operator to be cautious in the event that they may be heading for destruction of their boot drive of something.

pan64 · 03-04-2016, 12:33 AM

was already: http://www.linuxquestions.org/questi...7/#post5508971

and you will see how your input/variables were handled by the script

chrism01 · 03-04-2016, 02:33 AM

Use '$ans', not '&ans'