cannot use growisofs to write iso image

Hi,

this looks as if the '=' in /dev/sr0=ubuntu-16.04.6-desktop-amd64.iso
is interpreted by the shell parser as whitespace.

I get the message about genisoimage only if i do

  growisofs -speed=1 -dvd-compat -Z /dev/sr0 ubuntu-16.04.6-desktop-i386.iso

Then it says

  About to execute 'genisoimage ubuntu-16.04.6-desktop-i386.iso | builtin_dd of=/dev/sr4 obs=32k seek=0'

and lets genisoimage pack up the .iso file as only data file of a new ISO
filesystem which it then burns to DVD.
Without option -R or -J this yields the dull short file name.

If i run

  growisofs -speed=1 -dvd-compat -Z /dev/sr0=ubuntu-16.04.6-desktop-i386.iso

i get to see

  About to execute 'builtin_dd if=ubuntu-16.04.6-desktop-i386.iso of=/dev/sr4 obs=32k seek=0'

and the desired plain burn without genisoimage gets performed.

If i run with both, '=' and ' '

  growisofs -speed=1 -dvd-compat -use-the-force-luke=notray -Z /dev/sr0= ubuntu-16.04.6-desktop-i386.iso

i get

  :-( unable to open64("",O_RDONLY): No such file or directory

-----------------------------------------------------------------------

So somehow your shell parser and/or growisofs manage to neatly separate
/dev/sr0 from ubuntu-16.04.6-desktop-amd64.iso before they get used as
parameters for genisoimage and "buildin_dd".

To test the shell parser you could do:

  for i in /dev/sr0=ubuntu-16.04.6-desktop-amd64.iso ; do echo $i ; done

It should put out a single line

  /dev/sr0=ubuntu-16.04.6-desktop-amd64.iso

If you see two lines
  /dev/sr0
  ubuntu-16.04.6-desktop-amd64.iso
then the '=' was interpreted as white space.

growisofs itself is fewly maintained. If you get fed up with your smart
cat trick, be invited to try my programs cdrskin and xorrecord for image
burning.

Have a nice day :)

Thomas

Hi,

i made experiments with shell variable IFS which can declare '=' to
be white space.
When i do

  echo -n x"$IFS"x | od -c

i get

  0000000 x \t \n x
  0000005

(The 'x' are for better recognizing the gaps of blank characters.)

Contrary to my expectation, the shell loop "for" does not react on IFS:

  IFS="$IFS"=
  echo -n x"$IFS"x | od -c
  for i in /dev/sr0=ubuntu-16.04.6-desktop-amd64.iso ; do echo "$i" ; done )

yields

  0000000 x \t \n = x
  0000006
  /dev/sr0=ubuntu-16.04.6-desktop-amd64.iso

But with functions, built-in commands, and programs IFS would be a possible
explanation for growisofs' behavior:

  show_args() { for i in $@ ; do echo $i ; done; }
  show_args /dev/sr0=ubuntu-16.04.6-desktop-amd64.iso

yields

  /dev/sr0
  ubuntu-16.04.6-desktop-amd64.iso

Without seeing the '=', growisofs will employ genisoimage.

-----------------------------------------------------------------------

So what do you get from

  echo -n x"$IFS"x | od -c

Have a nice day :)

Thomas

For 'echo -n x"$IFS"x | od -c' I get:
0000000 x \t \n x
0000005

But based on your comments it seems quite likely I actually invoked it as '/dev/sr0 image.iso'. It is common to treat such things the same whether it's a single '='-separated argument to two separate arguments, and my cursory reading of the code suggested it intended to treat them the same. If the '=' is mandatory it is at certainly worth emphasising that in the docs.

I'm reluctant to do stand-alone experiments for this since I have only a few blank disks, but I'll aim to check this again when I have another image to write.

Hugo