diff --git a/content/en/2.general/5.linux/1.cli-basics.md b/content/en/2.general/5.linux/1.cli-basics.md index 17da8fc..9978154 100644 --- a/content/en/2.general/5.linux/1.cli-basics.md +++ b/content/en/2.general/5.linux/1.cli-basics.md @@ -153,8 +153,8 @@ Three silent commands, and `ls` showing the result: the copy sits next to the or Deletes. There is no recycle bin, no undo, no confirmation dialog. `-r` deletes a folder and its contents, `-f` forces without asking. -::warning -`rm -rf` is the command that wipes homelabs. It doesn't check, doesn't warn, and doesn't stop. Read the path twice before pressing :kbd{value="Enter"}, especially when the line starts with `sudo` and contains a `/` or a `*`. +::warning{to="/nonsense/bash/rm-confirmation"} +`rm -rf` is the command that wipes homelabs. It doesn't check, doesn't warn, and doesn't stop. Read the path twice before pressing :kbd{value="Enter"}, especially when the line starts with `sudo` and contains a `/` or a `*`. You can also prevent this by wrapping `sudo` in a small Bash function that asks **"are you sure?"** before it lets an `rm` through, covered in **rm confirmation guard**. :: ### cat and nano, read and edit diff --git a/content/en/2.general/5.linux/3.handy-tools.md b/content/en/2.general/5.linux/3.handy-tools.md index 11f9f75..2dc6f6b 100644 --- a/content/en/2.general/5.linux/3.handy-tools.md +++ b/content/en/2.general/5.linux/3.handy-tools.md @@ -198,3 +198,63 @@ Being outside `apt` also means it won't be updated by `apt full-upgrade`. Repeat #### Done ! :: + +## ufw, a firewall you can actually read + +Debian's firewall (`iptables`/`nftables` under the hood) is powerful and unreadable directly. `ufw`, *uncomplicated firewall*, is a thin layer on top that turns it into short, plain-English rules, block everything by default and open only what you actually expose. + +::steps{level="4"} +#### Install it + +```bash [Terminal] +sudo apt install ufw +``` + +#### Set the default policy + +```bash [Terminal] +sudo ufw default deny incoming +sudo ufw default allow outgoing +``` + +Nothing gets in unless a rule says so, everything the server itself initiates still goes out normally. + +#### Allow what you actually need + +```bash [Terminal] +sudo ufw allow OpenSSH +sudo ufw allow 443/tcp +``` + +`OpenSSH` is a built-in profile that matches the SSH port, no need to remember which one. Add one `allow` per port you expose, [SWAG](/serveex/core/swag) on `443` for instance. + +::warning +Allow SSH **before** enabling the firewall, in the next step. Enable it first and the very connection you're typing in gets cut, with no screen left plugged in to fix it. +:: + +#### Enable it + +```bash [Terminal] +sudo ufw enable +``` + +#### Check the rules + +```bash [Terminal] +sudo ufw status verbose +``` + +```console [Output] +Status: active +Logging: on (low) +Default: deny (incoming), allow (outgoing), disabled (routed) + +To Action From +-- ------ ---- +22/tcp (OpenSSH) ALLOW IN Anywhere +443/tcp ALLOW IN Anywhere +``` + +#### Done ! +:: + diff --git a/content/en/3.serveex/2.core/1.installation.md b/content/en/3.serveex/2.core/1.installation.md index bb17271..822b59c 100644 --- a/content/en/3.serveex/2.core/1.installation.md +++ b/content/en/3.serveex/2.core/1.installation.md @@ -93,6 +93,10 @@ Finish with *Finish partitioning and write changes to disk*, then confirm with * ![Debian installer partitioning scheme, all files in one partition](/img/serveex/install/debian-install-partition.png) +::tip{icon="" to="/general/linux/filesystem"} +✨ __Tip:__ what actually lives on that one partition, and why `/srv/docker` is where this guide puts every stack, is covered in **folders and partitions**. +:: + #### Mirror and surveys Answer *No* to *Scan another installation medium?*, everything else comes from the network. For the mirror, pick any one in your country, or `deb.debian.org` which routes to a nearby one automatically, and leave the HTTP proxy field empty unless you actually have one. The popularity contest (anonymous package statistics) is yes or no, no consequence either way. @@ -337,34 +341,6 @@ For security patches without having to think about it, `sudo apt install unatten - [Everything About Remote Console Access (SSH)](https://www.digitalocean.com/community/tutorials/ssh-essentials-working-with-ssh-servers-clients-and-keys) - Optional - [UPS Client in Case of Power Outage](https://www.sindastra.de/p/2078/how-to-connect-linux-server-to-synology-ups-server) / [also here](https://www.reddit.com/r/synology/comments/gtkjam/use_synology_nas_as_ups_server_to_safely_power/) -## Must-Have CLI Apps -Some essential apps you’ll likely need at some point, so might as well install them early: -```bash [Terminal] -sudo apt update -sudo apt upgrade -sudo apt install nano btop ranger git duf samba cifs-utils tree unzip -``` - -::note{to="/general/linux/handy-tools"} -What each of these does, plus a few more worth adding like `ncdu` and `lazydocker`, is detailed in **handy CLI tools**. -:: - -## Useful Features -### Firewall - -- [ufw](https://www.zenarmor.com/docs/network-security-tutorials/how-to-set-up-a-firewall-with-ufw-on-debian) -- [Firewalld](https://linuxcapable.com/how-to-install-firewalld-on-debian-linux/) - -### Samba Sharing (Access a Remote Network Disk) - -- [Create and Access a Samba Share](/general/networking/samba) - -### File Transfer via rsync - -```bash [Terminal] -sudo rsync -avhHSP /source /destination -``` -::note - -Add ` --exclude @eaDir`{lang=shell} if the source is a Synology NAS +::tip{icon="" to="/general/linux/handy-tools"} +✨ __Tip:__ a handful of terminal tools worth adding on top of a minimal install, `btop`, `duf`, `ufw` and a few more, are covered in **handy CLI tools**. :: diff --git a/content/en/5.nonsense/1.summary.md b/content/en/5.nonsense/1.summary.md index 66ee773..4829d34 100644 --- a/content/en/5.nonsense/1.summary.md +++ b/content/en/5.nonsense/1.summary.md @@ -75,4 +75,8 @@ Shut down the server if disks overheat ::card{icon="i-lucide-database-backup" title="Backrest Docker Stop" to="/nonsense/bash/backrest-docker-stop"} Stop containers safely around a Backrest backup :: + +::card{icon="i-lucide-shield-alert" title="rm Confirmation Guard" to="/nonsense/bash/rm-confirmation"} +A sudo wrapper that asks before it lets rm run +:: :: diff --git a/content/en/5.nonsense/3.bash/6.rm-confirmation.md b/content/en/5.nonsense/3.bash/6.rm-confirmation.md new file mode 100644 index 0000000..6f7c59c --- /dev/null +++ b/content/en/5.nonsense/3.bash/6.rm-confirmation.md @@ -0,0 +1,83 @@ +--- +title: rm Confirmation Guard +description: A small Bash function that wraps sudo and asks for confirmation before running rm, so a typo doesn't delete files owned by root. +--- + + +:ellipsis{left=0px width=40rem top=10rem blur=140px zIndex=60} + +`rm` doesn't ask twice. No recycle bin, no "are you sure", especially not with `sudo` in front of it, where a stray space or the wrong variable can wipe something you own no permission to double-check. It's the single most destructive habit a terminal builds into you, and the fix doesn't need a new tool, just a few lines in `.bashrc`. + +The idea is to shadow the `sudo` command with a Bash function of the same name. Every other use of `sudo` still goes straight through, but the moment the first argument is `rm`, it stops and asks first. + +```bash [.bashrc] +# rm confirmation +sudo() { + if [ "$1" = "rm" ]; then + echo -n "Are you sure you want to delete files/folders with sudo? (y/n) " + read ans + if [[ $ans == [Yy]* ]]; then + command sudo rm "${@:2}" + else + echo "Deletion cancelled." + fi + else + command sudo "$@" + fi +} +``` + +## How it works + +- `sudo() { ... }` defines a function named `sudo`. Bash looks up functions before it looks up commands on the `PATH`, so typing `sudo` in a terminal now runs this instead of `/usr/bin/sudo`, no alias trickery involved. +- `if [ "$1" = "rm" ]` only looks at the very first word after `sudo`. `sudo rm -rf /srv/docker/old-stack` matches, `sudo apt update` doesn't. +- On a match, it prints the question, reads the answer into `$ans`, and `[[ $ans == [Yy]* ]]` accepts `y`, `Y`, `yes`, anything starting with either case of Y. +- `command sudo rm "${@:2}"` is the part that actually deletes. `command` steps around the function so it doesn't call itself, and `${@:2}` is every argument after `rm`, so `-rf /srv/docker/old-stack` is passed through untouched. +- Anything that isn't `rm` falls into the `else` and runs exactly as if the function didn't exist: `command sudo "$@"`. + +## Installing it + +::steps{level="3"} +### Open your shell config + +```bash [Terminal] +nano ~/.bashrc +``` + +### Paste the function + +Add the block above at the end of the file, then save and exit. + +### Reload it + +```bash [Terminal] +source ~/.bashrc +``` + +### Try it + +```console [Terminal] +$ sudo rm -rf /tmp/test +Are you sure you want to delete files/folders with sudo? (y/n) n +Deletion cancelled. +``` + +Answer `y` and it runs for real. Anything that isn't `rm`, `sudo apt update`, `sudo systemctl restart docker`, goes through without a prompt. + +### Done ! +:: + +::note +This lives in `~/.bashrc`, so it only applies to your interactive shell, not to scripts, cron jobs, or another user's session. That's the point: it catches you, typing, not a program calling `sudo rm` on purpose. +:: + +## What it won't catch + +This is a habit-breaker, not a sandbox. It only fires when `rm` is the literal first word after `sudo`, so anything that reaches `rm` a different way skips it entirely: + +- `sudo -i rm -rf /` or `sudo su -c "rm -rf /"`, the first argument is `-i` or `su`, not `rm` +- `sudo bash -c "rm -rf /srv/docker"`, same reason, `rm` is buried inside the string bash runs +- `sudo find /srv/docker -delete`, deletes just as permanently, and never calls `rm` at all +- `rm` without `sudo` on files you already own + +Real protection against the last category is a proper backup, [Backrest](https://github.com/garethgeorge/backrest) and the [Docker stop script](/nonsense/bash/backrest-docker-stop) covered elsewhere in this section, or otherwise. This function is worth having anyway: the accidents it does catch are the ones that actually happen, a hurried `sudo rm -rf` with a typo in the path, not a deliberate attempt to work around it.