diff --git a/Makefile b/Makefile
index 4f256b0..34cefaa 100644
--- a/Makefile
+++ b/Makefile
@@ -32,9 +32,11 @@ $(foreach dir, $(categories), \
 	$(eval .dbs/$(dir).rec: $(wildcard $(dir)/*)) \
 	)
 
-.dbs/:
+%/:
 	mkdir $@
 
+include cmd.mk
+
 $(databases): .dbs/%.rec: %/ | .dbs/
 	$(info making $(@F))
 	for entry in $(shell find $< -type f -name "*.md") ; do \
diff --git a/basics/column.md b/basics/column.md
deleted file mode 100644
index 2738a14..0000000
--- a/basics/column.md
+++ /dev/null
@@ -1,36 +0,0 @@
----
-title: "column"
-tags: [ "basics", "format", "json" ]
----
-
-Put output into column.
-
-```sh
-du -h /etc/* | column
-```
-
-Reformat file with an explicit separator (`-s`):
-
-```sh
-column -ts: /etc/passwd
-```
-
-Give columns names (`-N`), so you can hide some (`-H`):
-
-```sh
-column -ts: -N User,PW,UID,GID,Description,Home,shell -H PW,GID /etc/passwd
-```
-
-Reorder with `-O` (unspecified items remain):
-
-
-```sh
-column -ts: -N User,PW,UID,GID,Description,Home,shell -H PW,GID -O User,Description,shell /etc/passwd 
-```
-
-Output to json format with `-J`:
-
-```sh
-column -J -ts: -H PW,GID,shell -N User,PW,UID,GID,Description,Home,shell /etc/passwd
-```
-
diff --git a/cmd.mk b/cmd.mk
new file mode 100644
index 0000000..552d6f0
--- /dev/null
+++ b/cmd.mk
@@ -0,0 +1,25 @@
+
+cmds != recsel command.rec -t command -G bin -U -CP bin
+lists = $(patsubst %,lists/%.md, $(cmds))
+
+default += $(lists)
+
+get_title = printf 'title: "%s"\n' '${1}'
+get_tags = recsel -t $(basename $<) $< -G bin \
+	-e 'bin = "$(1)"' -U -CP tag | \
+	sed 's/.*/"&",/g' | \
+	tr '\n' ' ' | \
+	sed 's/.*/tags: [ &]/'
+
+list_commands = recsel -t $(basename $<) $< -e 'bin = "$(1)"' | \
+	recfmt -f lists.fmt
+
+lists/%.md: command.rec | lists/
+	@printf '%s\n' '---' > $@
+	@$(call get_title,$(basename $(notdir $@))) >> $@
+	@$(call get_tags,$(basename $(notdir $@))) >> $@
+	@printf '\n%s\n' '---' >> $@
+	@$(call list_commands,$(basename $(notdir $@))) >> $@
+
+.PHONY: cmd
+cmd: $(lists) ## Bit lists of commands
diff --git a/command.rec b/command.rec
new file mode 100644
index 0000000..15c9f01
--- /dev/null
+++ b/command.rec
@@ -0,0 +1,51 @@
+%rec: command
+%doc: shell command examples
+%type: aim line
+%allowed: aim cmd bin tag
+
+aim: Put output into column
+cmd: du -h /etc/* | column
+bin: column
+tag: format
+
+aim: Reformat file with an explicit separator (`-s`)
+cmd: column -ts: /etc/passwd
+bin: column
+tag: format
+
+aim: Give columns names (`-N`), so you can hide some (`-H`)
+cmd: column -ts: -N User,PW,UID,GID,Description,Home,shell -H PW,GID /etc/passwd
+bin: column
+tag: format
+
+aim: Reorder with `-O` (unspecified items remain)
+cmd: column -ts: -N User,PW,UID,GID,Description,Home,shell -H PW,GID -O User,Description,shell /etc/passwd 
+bin: column
+tag: format
+
+aim: Output to json format with `-J`
+cmd: column -J -ts: -H PW,GID,shell -N User,PW,UID,GID,Description,Home,shell /etc/passwd
+bin: column
+tag: format
+tag: json
+
+aim: Make a QR Code image:
+cmd: qrencode 'https://play.google.com/store/apps/details?id=org.briarproject.briar.android' -o "$FILE".png
+bin: qrencode
+tag: qr
+
+aim: Make a QR Coded message in the terminal:
+cmd: qrencode -t ansi "Hello World"
+bin: qrencode
+tag: qr
+
+aim: Read a QR Code image:
+cmd: zbarimg $FILE
+bin: qrencode
+tag: qr
+
+aim: Show wifi QR code (only with Network Manager):
+cmd: nmcli device wifi show-password
+bin: qrencode
+tag: qr
+tag: wifi
diff --git a/lists.fmt b/lists.fmt
new file mode 100644
index 0000000..6bb67b5
--- /dev/null
+++ b/lists.fmt
@@ -0,0 +1,6 @@
+
+{{aim}}
+
+```{{shell}}
+{{cmd}}
+```
diff --git a/vision/qr_codes.md b/vision/qr_codes.md
deleted file mode 100644
index 24e4b22..0000000
--- a/vision/qr_codes.md
+++ /dev/null
@@ -1,28 +0,0 @@
----
-title: "QR Codes"
-tags: [ "qrencode", "zbar" ]
----
-
-Make a QR Code image:
-
-```sh
-qrencode 'https://play.google.com/store/apps/details?id=org.briarproject.briar.android' -o "$FILE".png
-```
-
-Make a QR Coded message in the terminal:
-
-```sh
-qrencode -t ansi "Hello World"
-```
-
-Read a QR Code image:
-
-```sh
-zbarimg $FILE
-```
-
-Show wifi QR code (only with Network Manager):
-
-```sh
-nmcli device wifi show-password
-```