allow ascii dependency map

Makefile

@@ -6,7 +6,7 @@ FZF != command -v sk || command -v fzy || command -v fzf || \
 
 spill_contents = sed -e '1,/---/d'
 
-help: ## Print the help message
+help: .git/info/exclude ## Print the help message
 	@awk 'BEGIN {FS = ":.*?## "} /^[0-9a-zA-Z._-]+:.*?## / {printf "\033[36m%s\033[0m : %s\n", $$1, $$2}' $(MAKEFILE_LIST) | \
 		sort | \
 		column -s ':' -t
@@ -19,6 +19,8 @@ categories = $(patsubst %/, %, $(dirs))
 databases = $(patsubst %, .dbs/%.rec, $(categories))
 
 default += $(databases)
+default += db.rec
+default += .dbs/map.fmt
 
 $(foreach dir, $(categories), \
 	$(eval .dbs/$(dir).rec: $(wildcard $(dir)/*)) \
@@ -26,6 +28,7 @@ $(foreach dir, $(categories), \
 
 .dbs/:
 	mkdir $@
+
 $(databases): .dbs/%.rec: %/ | .dbs/
 	$(info making $(@F))
 	for entry in $(shell find $< -type f -name "*.md") ; do \
@@ -38,6 +41,7 @@ $(databases): .dbs/%.rec: %/ | .dbs/
 
 # This two-variable read can only happen because of the quotes in the titles.
 db.rec: $(databases)
+	$(warning rebuilding from $? )
 	printf '%s\n' '%rec: guide' > $@
 	printf '%s\n' '%key: title' >> $@
 	printf '%s\n' '%type: requires rec guide' >> $@
@@ -55,10 +59,8 @@ db.rec: $(databases)
 	recfix --sort $@
 	$(info Created main database: $@)
 
-default += db.rec
-
 .git/info/exclude: $(default)
-	echo $^ | tr ' ' '\n' > $@
+	@echo $^ | tr ' ' '\n' > $@
 
 default += .git/info/exclude
 
@@ -76,6 +78,18 @@ article: ## Write an article
 	printf '%s\n\n' '---' >> $$path/$$filename.md ;\
 	$(EDITOR) +5 "$$path/$$filename.md"
 
+.dbs/map.fmt:| .dbs/
+	printf '%s\n' '[ {{requires[0]}} ] --> [ {{title}} ] {border-style: dashed;}' > $@
+	printf '%s\n' '[ {{requires[1]}} ] --> [ {{title}} ] {border-style: dashed;}' >> $@
+	printf '%s\n' '[ {{requires[2]}} ] --> [ {{title}} ] {border-style: dashed;}' >> $@
+	printf '%s\n' '[ {{requires[3]}} ] --> [ {{title}} ] {border-style: dashed;}' >> $@
+	printf '%s\n' '[ {{requires[4]}} ] --> [ {{title}} ] {border-style: dashed;}' >> $@
+
+.PHONY: map
+map: db.rec .dbs/map.fmt ## Show knowledge dependency map
+	recsel -t guide $< -e 'requires != ""' -p title,requires | recfmt -f .dbs/map.fmt |\
+	grep -vF '[  ]' | graph-easy --boxart | $${PAGER}
+
 .PHONY: clean
 clean: ## Remove all generated files
 	$(RM) $(default)

data/json.md

@@ -0,0 +1,13 @@
+---
+title: "ijq"
+tags: [ "data", "json", "TUI" ]
+---
+
+Analyse `json` easier with `ijq`.
+
+```sh
+column -J -ts: -H PW,GID,shell -N User,PW,UID,GID,Description,Home,shell /etc/passwd > host.json
+ijq !$
+```
+
+If you get stuck, try adding `.[]`.

system/ansible/ansible_with_docker.md

@@ -0,0 +1,114 @@
+---
+title: "Ansible with Docker"
+tags: [ "system", "ansible", "docker" ]
+requires: [ "Docker" ]
+---
+
+Set up two containers: `deb` and `arch`, add them to an `ansible` hosts file, then do a 'ping' to see if they respond.
+
+## Required Packages
+
+- `ansible`
+- `jq`
+- `docker`
+
+## Debian Container
+
+```sh
+docker run -di --rm --name deb --hostname deb debian
+docker exec -it deb sh -c 'apt update && apt -y install openssh-server python3 sudo'
+```
+
+Generate the host's ssh keys, then start the ssh daemon:
+
+```sh
+docker exec -it deb sh -c 'ssh-keygen -A'
+docker exec -d deb /usr/sbin/sshd -D
+```
+
+## Arch Linux Container
+
+```sh
+docker run -di --rm --name arch --hostname arch archlinux
+docker exec -it arch sh -c 'pacman -Syu --noconfirm python sudo openssh'
+docker exec -it arch sh -c 'ssh-keygen -A'
+docker exec -d arch /usr/sbin/sshd -D
+```
+
+## `ssh` Keys
+
+Copy across your public ssh key to the container's `authorized_keys` file:
+
+```sh
+pubkey=~/.ssh/id_rsa.pub
+for hostname in arch deb; do
+    docker cp $pubkey $hostname:/root/.ssh/authorized_keys
+    docker exec -it $hostname sh -c "chown -R root:root /root/.ssh/"
+    docker exec -it $hostname sh -c "chmod -R 700 /root/.ssh/"
+done
+```
+
+## Hosts File
+
+Find name of containers' IPv4 addresses.
+
+```sh
+docker network inspect bridge
+```
+
+The output is awful.
+Use `jq` to parse the `json`:
+
+```sh
+docker network inspect bridge  | jq -r '.[].Containers | .[].IPv4Address'
+```
+
+Now put those into a host file:
+
+```sh
+docker_hosts=hosts.txt
+echo '[containers]' > $docker_hosts
+
+docker network inspect bridge  | \
+    jq -r '.[].Containers | .[] | "root@" + .IPv4Address' | \
+    cut -d/ -f1 >> $docker_hosts
+```
+
+You may need to add those host keys to your known hosts file.
+Either connect interactively, or (for scripts):
+
+```sh
+hosts="$(docker network inspect bridge  | jq -r '.[].Containers | .[] | .Name + " " + .IPv4Address' | \
+    cut -d/ -f1)"
+
+echo "$hosts"
+
+echo "$hosts" | while read hostname ip; do
+    printf "%s" "$ip"
+    key="$(docker exec $hostname cat /etc/ssh/ssh_host_ed25519_key.pub)"
+    echo "$ip $key" >> ~/.ssh/known_hosts
+done
+```
+
+Check if they ping:
+
+```sh
+ansible -i $docker_hosts all -m ping
+```
+
+This command produces an irritating warning about the python interpreter (i.e., `python3`).
+
+Make the warning shut-up:
+
+```sh
+echo '
+[containers:vars]
+ansible_python_interpreter=/usr/bin/python3.13' >> $docker_hosts
+```
+
+Now the ping is cleaner:
+
+```sh
+ansible -i $docker_hosts all -m ping
+```
+

system/managing_groups.md

@@ -17,10 +17,10 @@ Remove yourself from all groups, and add yourself back to only `wheel`, `audio`,
 sudo usermod --groups wheel,audio,$USER
 ```
 
-Add yourself to the `wheel` group:
+Add yourself to the `docker` group:
 
 ```sh
-su root -c "usermod --append --groups wheel $USER"
+su root -c "usermod --append --groups docker $USER"
 ```
 Add yourself to the `network` group:
 
@@ -28,5 +28,11 @@ Add yourself to the `network` group:
 sudo usermod -aG network $USER
 ```
 
-The changes will not take effect until you log in again, so reboot or log into `localhost` with [ssh](../networking/ssh.md).
+The changes have not taken effect, so log into your own account again with `su`:
 
+
+```sh
+groups
+sudo su $USER
+groups
+```

virtualization/docker.md

@@ -1,6 +1,7 @@
 ---
 title: "Docker"
 tags: [ "documentation", "virtualization" ]
+requires: [ "Managing Groups" ]
 ---
 ```sh
 sudo pacman -S docker