diff --git a/.config/systemd/user/garmin-dump.service b/.config/systemd/user/garmin-dump.service
index ab8db7f..652ae9f 100644
--- a/.config/systemd/user/garmin-dump.service
+++ b/.config/systemd/user/garmin-dump.service
@@ -5,7 +5,7 @@ StartLimitBurst=4
 
 [Service]
 Type=oneshot
-ExecStart=%h/.local/bin/garmin-dump
+ExecStart=%h/.local/bin/db-dump negsplit Garmin week
 # MariaDB not up yet (e.g. caught up right after boot)? retry a few times
 Restart=on-failure
 RestartSec=5min
diff --git a/.config/systemd/user/library-dump.service b/.config/systemd/user/library-dump.service
index 261513e..9372565 100644
--- a/.config/systemd/user/library-dump.service
+++ b/.config/systemd/user/library-dump.service
@@ -5,7 +5,7 @@ StartLimitBurst=4
 
 [Service]
 Type=oneshot
-ExecStart=%h/.local/bin/library-dump
+ExecStart=%h/.local/bin/db-dump library_manager Library day
 # MariaDB not up yet (e.g. caught up right after boot)? retry a few times
 Restart=on-failure
 RestartSec=5min
diff --git a/.config/systemd/user/weather-dump.service b/.config/systemd/user/weather-dump.service
index 2793953..65e9759 100644
--- a/.config/systemd/user/weather-dump.service
+++ b/.config/systemd/user/weather-dump.service
@@ -5,7 +5,7 @@ StartLimitBurst=4
 
 [Service]
 Type=oneshot
-ExecStart=%h/.local/bin/weather-dump
+ExecStart=%h/.local/bin/db-dump ens-forecast Weather week
 # MariaDB not up yet (e.g. caught up right after boot)? retry a few times
 Restart=on-failure
 RestartSec=5min
diff --git a/.local/bin/db-dump b/.local/bin/db-dump
new file mode 100755
index 0000000..de8b7fa
--- /dev/null
+++ b/.local/bin/db-dump
@@ -0,0 +1,38 @@
+#!/bin/bash
+# Usage: db-dump PROJECT DATABASE week|day
+# Dump a MariaDB database to ~/.local/share/PROJECT/dumps with login ~/.config/PROJECT/dump.cnf.
+# week: per-ISO-week files, keeping the two newest; day: per-weekday files (seven self-rotating copies).
+set -euo pipefail
+
+if (($# != 3)) || [[ $3 != week && $3 != day ]]; then
+    echo "usage: ${0##*/} PROJECT DATABASE week|day" >&2
+    exit 2
+fi
+project=$1 db=$2 mode=$3
+
+cnf=${XDG_CONFIG_HOME:-$HOME/.config}/$project/dump.cnf
+dir=${XDG_DATA_HOME:-$HOME/.local/share}/$project/dumps
+if [[ $mode == week ]]; then
+    out=$dir/$db-$(date +%G-W%V).sql.gz
+else
+    out=$dir/$db-$(LC_ALL=C date +%a).sql.gz
+fi
+keep=2
+
+umask 077
+mkdir -p "$dir"
+
+# Write to a temporary file so a failed dump never replaces a good one
+tmp=$(mktemp "$dir/.dump.XXXXXX")
+trap 'rm -f "$tmp"' EXIT
+
+mariadb-dump --defaults-extra-file="$cnf" --single-transaction --databases "$db" | gzip > "$tmp"
+mv "$tmp" "$out"
+
+# Weekly names sort by week, so all but the last $keep are the old ones
+if [[ $mode == week ]]; then
+    dumps=("$dir/$db"-[0-9][0-9][0-9][0-9]-W[0-9][0-9].sql.gz)
+    if ((${#dumps[@]} > keep)); then
+        rm -f -- "${dumps[@]:0:${#dumps[@]}-keep}"
+    fi
+fi
diff --git a/.local/bin/garmin-dump b/.local/bin/garmin-dump
deleted file mode 100755
index a8bdee0..0000000
--- a/.local/bin/garmin-dump
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/bin/bash
-# Dump the Garmin database to a per-ISO-week file, keeping the two newest weeks.
-set -euo pipefail
-
-cnf=${XDG_CONFIG_HOME:-$HOME/.config}/negsplit/dump.cnf
-dir=${XDG_DATA_HOME:-$HOME/.local/share}/negsplit/dumps
-out=$dir/Garmin-$(date +%G-W%V).sql.gz
-keep=2
-
-umask 077
-mkdir -p "$dir"
-
-# Write to a temporary file so a failed dump never replaces a good one
-tmp=$(mktemp "$dir/.dump.XXXXXX")
-trap 'rm -f "$tmp"' EXIT
-
-mariadb-dump --defaults-extra-file="$cnf" --single-transaction --databases Garmin | gzip > "$tmp"
-mv "$tmp" "$out"
-
-# Names sort by week, so all but the last $keep are the old ones
-dumps=("$dir"/Garmin-*.sql.gz)
-if (( ${#dumps[@]} > keep )); then
-    rm -f -- "${dumps[@]:0:${#dumps[@]}-keep}"
-fi
diff --git a/.local/bin/library-dump b/.local/bin/library-dump
deleted file mode 100755
index 7abffcd..0000000
--- a/.local/bin/library-dump
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/bin/bash
-# Dump the Library database to a per-weekday file (seven self-rotating copies).
-set -euo pipefail
-
-cnf=${XDG_CONFIG_HOME:-$HOME/.config}/library_manager/dump.cnf
-dir=${XDG_DATA_HOME:-$HOME/.local/share}/library_manager/dumps
-out=$dir/Library-$(LC_ALL=C date +%a).sql.gz
-
-umask 077
-mkdir -p "$dir"
-
-# Write to a temporary file so a failed dump never replaces a good one
-tmp=$(mktemp "$dir/.dump.XXXXXX")
-trap 'rm -f "$tmp"' EXIT
-
-mariadb-dump --defaults-extra-file="$cnf" --single-transaction --databases Library | gzip > "$tmp"
-mv "$tmp" "$out"
diff --git a/.local/bin/weather-dump b/.local/bin/weather-dump
deleted file mode 100755
index 9e092de..0000000
--- a/.local/bin/weather-dump
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/bin/bash
-# Dump the Weather database (ens-forecast) to a per-ISO-week file, keeping the two newest weeks.
-set -euo pipefail
-
-cnf=${XDG_CONFIG_HOME:-$HOME/.config}/ens-forecast/dump.cnf
-dir=${XDG_DATA_HOME:-$HOME/.local/share}/ens-forecast/dumps
-out=$dir/Weather-$(date +%G-W%V).sql.gz
-keep=2
-
-umask 077
-mkdir -p "$dir"
-
-# Write to a temporary file so a failed dump never replaces a good one
-tmp=$(mktemp "$dir/.dump.XXXXXX")
-trap 'rm -f "$tmp"' EXIT
-
-mariadb-dump --defaults-extra-file="$cnf" --single-transaction --databases Weather | gzip > "$tmp"
-mv "$tmp" "$out"
-
-# Names sort by week, so all but the last $keep are the old ones
-dumps=("$dir"/Weather-*.sql.gz)
-if (( ${#dumps[@]} > keep )); then
-    rm -f -- "${dumps[@]:0:${#dumps[@]}-keep}"
-fi