Improve backup and restore scripts

[sylirre]

Drop piped input and output in favor of maintaining versatile backup options. Breaking change but I don't think that removed pipe feature will be a big deal.

[agnostic-apollo]

Should probably check if home or prefix are under each other, like if rootfs equals prefix .../files and home is at .../files/home.

https://github.com/termux/termux-packages/blob/22641beab1a72fea849590e1b4b514d5720655b5/scripts/properties.sh#L923

[robertkirkman]

Thank you!

It's a good timing, I needed to back up and a restore a really large 42 GB Termux installation. I tested this PR by backing up and restoring from this PR version and everything worked great.

I used this from my Termux home folder:

~ $ termux-backup --home --packages /storage/emulated/0/termux_backup.tar.gz

Something I would like to note is that it was not able to back up my .suroot folder (this is the secret home folder of the system root user in Termux, since while we say Termux is a "single user system", technically reality is more complicated because people who have root do have access to that second user, so Termux is a "single user system except when it isn't").

Any files I might have wanted to save from my root projects are not backed up by that. "projects" is quite general and could include many settings or data, for example the Bash History file of the root user in Termux. I saw errors like this:

tar: ./home/.suroot/.bashrc: Cannot open: Permission denied

I wondered, if I were to use sudo su, cd $HOME and then use the command termux-backup --home /storage/emulated/0/termux_suroot_backup.tar.gz, would that be expected to create another backup, of just my root home folder? I didn't really want to post this without at least trying it on myself to see what would happen, and what happened is actually that my entire home folder was backed up, but this time including .suroot without failing to include it, which is pleasant.

I think there is only a minor difference between what I as a user expected, and what happened, which is that I thought --home would only back up my .suroot folder if run as root, which could save space in my backup if I want to do it this way, by first backing up my termux user home folder, then my root user home folder separately. If trying to infer the desired home folder from the $HOME variable would be bad for some reason, then you don't need to do that, I am just wondering whether it could work like that.

[sylirre]

It back ups only original Termux prefix and home. It won't let override these directories through environment variables.

.suroot will get automatically excluded if can't be read by tar