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I have a Clonezilla installation on a USB stick and I'd like to make some modifications to the operating system. Specifically, I'd like to insert a runnable script into /usr/sbin to make it easy to run my own backup command to make backups less painful.
The main filesystem lives under /live/filesystem.squashfs on the USB FAT-32 partition.
How can I mount this read/write on my Linux machine in order to be able to add/remove/change files? I'm running an Ubuntu 12.04 derivative.
As root, copy filesystem.squashfs to some empty dir, e.g.:
cp /mnt/clonezilla/live/filesystem.squashfs /path/to/workdir
cd /path/to/workdir
Unpack the file then move it somewhere else (so you still have it as a backup):
unsquashfs filesystem.squashfs
mv filesystem.squashfs /path/to/backup/
Go in squashfs-root, add/modify as per your taste then recreate filesystem.squashfs:
cd /path/to/workdir
mksquashfs squashfs-root filesystem.squashfs -b 1024k -comp xz -Xbcj x86 -e boot
copy the newly created filesystem.squashfs over the existing one on your USB drive, e.g.:
cp filesystem.squashfs /mnt/clonezilla/live/
then reboot and use your LIVE USB.
Note: the above commands are part of squashfs-tools.
Source directory entry bin already used! - trying bin_1. Sure enough, in my output filesystem, I have a /bin and a /bin_1, rather than merging the folder. Any ideas? If I run with -noappend, the filesystem simply doesn't work.
– Naftuli Kay
Jun 23 '13 at 19:25
/usr/bin and repacking with mksquashfs. USB drive boots fine and I can use my script from the live session. Make sure you no longer have the old filesystem.squashfs in the same directory with your modified squashfs-root before running mksquashfs.
– don_crissti
Jun 23 '13 at 19:53
create_inode: could not create character device squashfs-root/dev/audio, because you're not superuser!
– Wilf
Aug 8 '18 at 9:43
squashfs-root/dev/*) as regular user, you need root privileges.
– don_crissti
Aug 8 '18 at 10:26
If your system supports some uion-filesystem, such as aufs or overlayfs, you don't have to extract your original squashfs file.
For example the overlayfs is used( a kernel option to enable it): You can mount your squashfs.file to /fm or somewhere else first. Prepare a writable filesystem with 2 directories in it, say /to and /temp. prepare another writable directory /fin for the merged results. Mount them together as an overlayfs to your system ---
mount -t overlay -o lowerdir=/fm,upperdir=/to,workdir=/temp overlay /fin
Now you can add/modify files in /fin. Once everything done, you can mksquashfs /fin to a new squashfs file,
mksquashfs /fin newfile; umount /fin
, then clear/unmount all the other used directories as you will.
The squashfs and some unionfs are commonly used for a live-cd.
Here, I found an other answer:
bash# mount dir.sqsh /mnt/dir -t squashfs -o loop
Using overlayfs as shown is the best way to have pseudo "squashfs rw" ; It requires however to run on > 4.x kernel (or ubuntu >14.x trusty ).
An alternative solution when one is sitting on older live cd without any overlayfs/aufs/unionfs is to make use of squashfs'own capabilities
Important: Without unsquashfs, so this can be done on low storage system
Example:
Modify squashfs's "usr" directory
mount squashfs_file /mnt # 1
cp -a /mnt/usr $HOME # 2 Modify whatever $HOME/usr as needed
mksquashfs /mnt new_squashfs_file -wildcards -e usr # 3
mksquashfs $HOME/usr new_squashfs_file -keep-as-directory # 4
umount /mnt # 5 Cleanup
Line 3 builds temporarily squashfsfile excluding olddir_usr
Line 4 appends modified-usr-dir into new_squashfsfile
See here append squashfs
