Update README.md

README.md

@@ -1,26 +1,128 @@
 # fedora-immutable-cheatsheet
+
 A cheatsheet for immutable fedora variants, usually about ostree and rpm-ostree
-## system files health checking
+
+## System files health checking
+
 Finding all damaged objects. `--delete` flag will delete corrupted files and mark commits with damaged files as "partial", which then allow to redownload it.
 ```bash
 ostree fsck -a
 ```
 
-current deployment status
+Current deployment status
 ```bash
 rpm-ostree status
 ```
 
-## todo
+## Emergency fallback
+
+### falling back to any previous commit of the system branch
+
+1. Download last 5 commits
+   
+```bash
+ostree pull --depth 5 fedora fedora/38/x86_64/kinoite
+```
+
+2. (Optionally) pin current deployment if there is chance of need to return to it. 0 is index of current deployment. to list deploymends run `rpm-ostree status` or `ostree admin status`
+
+```bash
+ostree admin pin 0
+```
+
+3. List downloaded commits to choose the best one, basing on the timestamp or anything elese
+
 ```bash
 ostree log fedora/38/x86_64/kinoite
-ostree pull --depth 2 fedora fedora/38/x86_64/kinoite
+```
-ostree pull fedora fedora/38/x86_64/kinoite
+
-ostree admin pin 0
+4. Deploy selected commit using its hash
-ostree admin pin -u 1
+
-rpm-ostree rebase fedora/38/x86_64/kinoite
+```bash
-rpm-ostree cleanup -p -b -r -m
-rpm-ostree usroverlay
 rpm-ostree deploy 520e744c643b85fd14817a3eb948f200e7dec902cad4157e411dfeda2c6d7aab
+```
+
+5. Reboot into the new deoloyment (to see it before reboot, run `rpm-ostree status`)
+
+6. (Optionally) unpin previously pinned deployment (id will be 1 if it is listed as the one before currently booted one)
+
+```bash
+ostree admin pin -u 1
+```
+
+### Rebase into different tree (also for switching flavors of the distro)
+
+1. List trees of the ostree repository (fedora example)
+
+```bash
+ostree remote summary fedora
+```
+
+2. Rebase the system into the selected tree
+
+```bash
+rpm-ostree rebase fedora/39/x86_64/kinoite
+```
+
+3. reboot into the new deployment
+
+## cleaning
+
+Main tool for cleanup is `rpm-ostree cleanup` command. To see all options run:
+
+```bash
+rpm-ostree cleanup --help
+```
+
+Full cleanup (including all deployments other than currently deployed)
+```bash
+rpm-ostree cleanup -p -b -r -m
+```
+
+ostree also have cleaning tool
+
+```bash
 ostree prune
 ```
+
+## Managing packages deployed with system
+
+Adding package fzf to the (new) deployment
+
+```bash
+rpm-ostree install fzf
+```
+
+Removing packgage that was additionally installed
+
+```bash
+rpm-ostree remove fzf
+```
+
+Removing package that is in the system by default
+
+```bash
+rpm-ostree override remove firefox
+```
+
+Restore default package that was removed with override
+
+```bash
+rpm-ostree override reset firefox
+```
+
+## Other
+
+### Allow system modification
+
+Temporarily
+
+```bash
+rpm-ostree usroverlay --transient
+````
+
+Make the changes to `/usr` persist reboots
+
+```bash
+rpm-ostree usroverlay --hotfix
+```