#######
#
# E-scripts on using the loop devices.
#
# Note 1: use the eev command (defined in eev.el) and the
# ee alias (in my .zshrc) to execute parts of this file.
# Executing this file as a whole makes no sense.
# An introduction to eev can be found here:
#
#   (find-eev-quick-intro)
#   http://angg.twu.net/eev-intros/find-eev-quick-intro.html
#
# Note 2: be VERY careful and make sure you understand what
# you're doing.
#
# Note 3: If you use a shell other than zsh things like |&
# and the for loops may not work.
#
# Note 4: I always run as root.
#
# Note 5: some parts are too old and don't work anymore. Some
# never worked.
#
# Note 6: the definitions for the find-xxxfile commands are on my
# .emacs.
#
# Note 7: if you see a strange command check my .zshrc -- it may
# be defined there as a function or an alias.
#
# Note 8: the sections without dates are always older than the
# sections with dates.
#
# This file is at <http://angg.twu.net/e/loop.e>
#           or at <http://angg.twu.net/e/loop.e.html>.
#        See also <http://angg.twu.net/emacs.html>,
#                 <http://angg.twu.net/.emacs[.html]>,
#                 <http://angg.twu.net/.zshrc[.html]>,
#                 <http://angg.twu.net/escripts.html>,
#             and <http://angg.twu.net/>.
#
#######




# «.blkid»		(to "blkid")
# «.losetup»		(to "losetup")
# «.partx»		(to "partx")
# «.two-partitions»	(to "two-partitions")



* (eepitch-shell)
* (eepitch-kill)
* (eepitch-shell)
# This takes 20 seconds or more...
time cp -v $S/http/mirror.fsf.org/trisquel-images/trisquel-mini_8.0_amd64.iso /tmp/trisquel.iso


# https://en.wikipedia.org/wiki/Loop_device
# (find-esgrep "grep -nH -e loop *.e")
# (find-esgrep "grep -nH -e loop *.e | grep -v loops")
# (find-esgrep "grep -nH -e losetup *.e")
# (find-man "1 man" "man -k printf")
# (find-sh "man -k printf")
# (find-sh "man -k loop")

# (find-es "trisquel" "pen-drive-2018")
# (find-es "qemu" "qemu-2018")





partitions


/tmp/trisquel.iso



#####
#
# blkid
# 2018mai08
#
#####

# «blkid» (to ".blkid")
# (find-man "8 blkid")
# (find-sh "blkid -h")
# (find-sh "blkid -k")
# (find-fline "/etc/blkid.conf")
# (find-fline "/etc/" "blkid.tab")
blkid
sudo blkid -p /dev/sda
sudo blkid -p /dev/sda1
sudo blkid -p /dev/sda1 | tr ' ' '\n'
sudo blkid -p /dev/sda2 | tr ' ' '\n'
sudo blkid -p /dev/sda3 | tr ' ' '\n'
sudo blkid -p /dev/sda4 | tr ' ' '\n'
sudo blkid -p /dev/sda5 | tr ' ' '\n'
sudo blkid -p /dev/sda6 | tr ' ' '\n'
sudo blkid -p /dev/sda7 | tr ' ' '\n'
sudo blkid -p /dev/sda8 | tr ' ' '\n'





#####
#
# losetup
# 2018mai08
#
#####

# «losetup» (to ".losetup")
# (find-man "8 losetup")
# (find-man "8 losetup" "-a, --all")
# (find-man "8 losetup" "-f, --find")
# (find-man "8 losetup" "-o, --offset offset")
# (find-man "8 losetup" "-j, --associated file")
# (find-man "8 mount")
# (find-man "8 mount" "THE LOOP DEVICE")
# (find-man "8 mount" "THE LOOP DEVICE" "offset")

# (find-fline "/dev/" "loop")

laf /dev/loop*
sudo losetup --show /dev/loop0
sudo losetup -f /tmp/trisquel.iso

sudo losetup --find       /tmp/trisquel.iso
sudo losetup --find       /tmp/trisquel.iso
sudo losetup --associated /tmp/trisquel.iso
sudo losetup --show       /dev/loop0
sudo losetup              /dev/loop0
sudo losetup              /dev/loop1
sudo losetup --detach     /dev/loop0
sudo losetup --detach     /dev/loop1
sudo losetup --associated /tmp/trisquel.iso

sudo losetup   /dev/loop4 /tmp/trisquel.iso
sudo losetup --associated /tmp/trisquel.iso
sudo losetup              /dev/loop4
sudo losetup --detach     /dev/loop4
sudo losetup --associated /tmp/trisquel.iso





#####
#
# partx
# 2018mai08
#
#####

# «partx» (to ".partx")
# https://dustymabe.com/2012/12/15/mounting-a-partition-within-a-disk-image/
# https://www.suse.com/c/accessing-file-systems-disk-block-image-files/
# (find-man "8 partx")
# (find-man "8 partx" "-a, --add")
# (find-man "8 partx" "-d, --delete")
# (find-man "8 partx" "-s, --show")
# (find-fline "/dev/" "loop")

# This works:
#
partx --show -            /tmp/trisquel.iso
#
sudo losetup   /dev/loop4 /tmp/trisquel.iso
sudo partx --show -       /dev/loop4
sudo partx --add          /dev/loop4
laf /dev/loop*
#
mkdir /tmp/tris1
sudo mount -o ro /dev/loop4p1 /tmp/tris1
  # (find-fline              "/tmp/tris1/")
sudo umount                   /tmp/tris1
sudo partx --delete   /dev/loop4
#
sudo losetup          /dev/loop4
sudo losetup --detach /dev/loop4
sudo losetup          /dev/loop4



# This works:
#
sudo losetup   /dev/loop4 /tmp/trisquel.iso
sudo partx --show -       /dev/loop4
sudo partx --add          /dev/loop4
sudo partx --delete       /dev/loop4
sudo losetup --detach     /dev/loop4


# This works:
#
sudo losetup /dev/loop4       /tmp/trisquel.iso
sudo partx --show -           /dev/loop4
sudo partx --add              /dev/loop4
mkdir /tmp/tris1
sudo mount -o ro /dev/loop4p1 /tmp/tris1
sudo umount                   /tmp/tris1
sudo partx --delete           /dev/loop4
sudo losetup --detach         /dev/loop4
sudo losetup                  /dev/loop4


# This works:
#
sudo losetup /dev/loop4       /tmp/trisquel.iso
sudo partx --show -           /dev/loop4
sudo partx --add              /dev/loop4
mkdir -p /tmp/tris1
sudo mount -o ro /dev/loop4p1 /tmp/tris1
laf                           /tmp/tris1/casper/filesystem.squashfs
sudo losetup /dev/loop5       /tmp/tris1/casper/filesystem.squashfs
mkdir -p /tmp/tris1s
sudo mount -o ro /dev/loop5   /tmp/tris1s
# (find-fline                "/tmp/tris1s/")
sudo umount                   /tmp/tris1s
sudo losetup --detach         /dev/loop5
sudo umount                   /tmp/tris1
sudo losetup --detach         /dev/loop4
sudo partx --delete           /dev/loop4






#####
#
# Creating two partitions in a loop device
# 2018mai21
#
#####

# «two-partitions» (to ".two-partitions")
# (find-es "grub" "grub-pen-drive-2018")
# (find-es "grub" "ext2-embedding-not-possible")

* (eepitch-shell)
* (eepitch-kill)
* (eepitch-shell)
# (find-man "dd")
mount


# Clean up from a previous run
#
sudo umount /tmp/pengrub1
sudo umount /tmp/pengrub2
sudo losetup --detach /dev/loop4
rm -v /tmp/pengrub1/
rm -v /tmp/pengrub2/
rm -v /tmp/pengrub.img


# Create /tmp/pengrub.img and point /dev/loop4 to it
#
dd bs=1M count=100 if=/dev/zero of=/tmp/pengrub.img
ls -lAFh /tmp/pengrub.img
sudo losetup /dev/loop4 /tmp/pengrub.img


# Create two partitions in /dev/loop4
# (find-man "8 fdisk")
#
sudo fdisk /dev/loop4
n
p
1

+50M
p
n
p
2


p
m
w

sudo fdisk -l /dev/loop4


# Format the partitions
# (find-man "8 partprobe")
# (find-man "8 partx" "are in 512-byte sectors")
#
sudo partx --show /dev/loop4
sudo partprobe    /dev/loop4
sudo mke2fs       /dev/loop4p1
sudo mke2fs       /dev/loop4p2

# sudo losetup --detach /dev/loop4


# Mount the partitions
#
mkdir /tmp/pengrub1/
mkdir /tmp/pengrub2/
sudo losetup /dev/loop4 /tmp/pengrub.img
sudo mount -o loop /dev/loop4p1 /tmp/pengrub1
sudo mount -o loop /dev/loop4p2 /tmp/pengrub2

# (find-fline "/tmp/pengrub1/")
# (find-fline "/tmp/pengrub2/")


# Umount the partitions
#
sudo umount /tmp/pengrub1
sudo umount /tmp/pengrub2
sudo losetup --detach /dev/loop4





# (find-grubnode "Invoking grub-install")
# sudo grub-install /dev/loop4
# sudo grub-install /dev/pengrub1









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#  coding:               utf-8-unix
#  End: