Add rsync sync command

6 files changed, 451 insertions, 7 deletions

diff --git a/README.md b/README.md
index 5df5d71..52b0bd4 100644
--- a/README.md
+++ b/README.md
@@ -41,6 +41,7 @@ modern `magick` command and falls back to `convert` when needed.
 photoalbum --init
 photoalbum --generate [--config PATH] [OPTIONS]
 photoalbum --refresh-splash [--config PATH] [OPTIONS]
+photoalbum --sync [--config PATH] [OPTIONS]
 photoalbum --dry-run [--config PATH] [OPTIONS]
 photoalbum --print-config [--config PATH] [OPTIONS]
 photoalbum --clean [--config PATH] [OPTIONS]
@@ -51,6 +52,8 @@ photoalbum --version
   default config. It refuses to overwrite an existing file.
 * `--generate` builds the static album.
 * `--refresh-splash` rewrites only the generated root splash page.
+* `--sync` publishes the generated output directory to configured rsync
+  destinations.
 * `--dry-run` loads the config and overrides, validates the planned generation,
   and prints the effective paths, image count, tarball plan, and generated file
   plan without writing output or running ImageMagick or tar.
@@ -69,7 +72,7 @@ If the file is missing, run `photoalbum --init` first.
 The config file is a Bash file with assignments such as `INCOMING_DIR`,
 `DIST_DIR`, `TEMPLATE_DIR`, `TITLE`, `HEIGHT`, `THUMBHEIGHT`, `MAXPREVIEWS`,
 `IMAGE_JOBS`, `IMAGEMAGICK_TIMEOUT`, `RANDOM_SEED`, `SHUFFLE`, `SPLASH_PAGE`,
-`TARBALL_INCLUDE`, and `TAR_TIMEOUT`.
+`TARBALL_INCLUDE`, `TAR_TIMEOUT`, `SYNC_DELETE`, and `SYNC_DESTINATIONS`.
 
 Before generating, `photoalbum` validates the loaded config and command-line
 overrides. It checks required values, positive integer settings, `yes`/`no`
@@ -90,9 +93,10 @@ tarball filename uses `<timestamp>` as a placeholder so the output is stable.
 `CONFIG_SOURCE`, `INCOMING_DIR`, `DIST_DIR`, `TEMPLATE_DIR`, `TITLE`, `HEIGHT`,
 `THUMBHEIGHT`, `MAXPREVIEWS`, `IMAGE_JOBS`, `IMAGEMAGICK_TIMEOUT`,
 `RANDOM_SEED`, `SHUFFLE`, `SPLASH_PAGE`, `TARBALL_INCLUDE`,
-`TARBALL_SUFFIX`, `TAR_TIMEOUT`, `TAR_OPTS`, and `ORIGINAL_BASEPATH`.
-Scalar values use Bash `%q` quoting and `TAR_OPTS` is normalized to a Bash array
-assignment, so the output can be parsed by shell tooling. `--quiet` does not
+`TARBALL_SUFFIX`, `TAR_TIMEOUT`, `TAR_OPTS`, `SYNC_DELETE`,
+`SYNC_DESTINATIONS`, and `ORIGINAL_BASEPATH`. Scalar values use Bash `%q`
+quoting and `TAR_OPTS` and `SYNC_DESTINATIONS` are normalized to Bash array
+assignments, so the output can be parsed by shell tooling. `--quiet` does not
 suppress this output, and `--verbose` does not add human-readable diagnostics to
 it.
 
@@ -120,6 +124,11 @@ The following long options override config values:
 | `--no-splash` | `SPLASH_PAGE=no` |
 | `--tarball` | `TARBALL_INCLUDE=yes` |
 | `--no-tarball` | `TARBALL_INCLUDE=no` |
+| `--sync-delete` | `SYNC_DELETE=yes` |
+| `--no-sync-delete` | `SYNC_DELETE=no` |
+
+Pass `--sync-destination DEST` one or more times with `--sync` to override the
+configured sync destinations for that run.
 
 By default, the generated root `index.html` is a no-JavaScript splash page using
 a randomly selected album photo. Set `SPLASH_PAGE=no` or pass `--no-splash` to
@@ -137,6 +146,20 @@ timestamps, and `--shuffle` preview order remain non-deterministic. Set
 choices repeatable for stable tests or reproducible album builds. Use the same
 seed and inputs to produce the same HTML.
 
+To publish generated output, configure destinations and run `photoalbum --sync`:
+
+```
+SYNC_DESTINATIONS=(
+    admin@fishfinger.buetow.org:/var/www/htdocs/example.org/
+    admin@blowfish.buetow.org:/var/www/htdocs/example.org/
+)
+```
+
+`--sync` runs `rsync -av --delete "$DIST_DIR/" "$destination"` for each
+destination by default. The trailing slash on `DIST_DIR/` means the generated
+contents are copied into the target directory. Set `SYNC_DELETE=no` or pass
+`--no-sync-delete` to omit `--delete`.
+
 `--dry-run`, `--print-config`, and `--refresh-splash` accept the same override
 options as `--generate`. `--clean` accepts the same override options, but only
 `--dist` changes what it removes.
@@ -163,7 +186,7 @@ value to a positive integer to adjust the limit for large images or archives.
    pictures and adjust `DIST_DIR`, `TITLE`, or template settings as needed.
 3. Run `photoalbum --dry-run` to inspect the planned generation.
 4. Run `photoalbum --generate` to generate the album.
-5. Distribute the `./dist` directory to a static web server.
+5. Run `photoalbum --sync` to publish `./dist`, or distribute it manually.
 6. Run `photoalbum --clean` to remove the generated output.
 
 ## HTML templates
diff --git a/bin/photoalbum b/bin/photoalbum
index d872179..6566c69 100755
--- a/bin/photoalbum
+++ b/bin/photoalbum
@@ -23,6 +23,7 @@ declare -ra CLI_CONFIG_OVERRIDE_TARGETS=(
     RANDOM_SEED
     SHUFFLE
     SPLASH_PAGE
+    SYNC_DELETE
     TARBALL_INCLUDE
 )
 declare -Ar CLI_OPTION_KIND=(
@@ -42,6 +43,9 @@ declare -Ar CLI_OPTION_KIND=(
     [--no-splash]=flag
     [--tarball]=flag
     [--no-tarball]=flag
+    [--sync-delete]=flag
+    [--no-sync-delete]=flag
+    [--sync-destination]=value
     [--verbose]=output
     [--quiet]=output
     [--version]=action
@@ -49,6 +53,7 @@ declare -Ar CLI_OPTION_KIND=(
     [--clean]=action
     [--generate]=action
     [--refresh-splash]=action
+    [--sync]=action
     [--dry-run]=action
     [--print-config]=action
 )
@@ -64,6 +69,8 @@ declare -Ar CLI_OPTION_VALUE=(
     [--no-splash]=no
     [--tarball]=yes
     [--no-tarball]=no
+    [--sync-delete]=yes
+    [--no-sync-delete]=no
     [--verbose]=verbose
     [--quiet]=quiet
 )
@@ -83,9 +90,12 @@ declare -Ar CLI_OPTION_CONFIG_TARGET=(
     [--no-splash]=SPLASH_PAGE
     [--tarball]=TARBALL_INCLUDE
     [--no-tarball]=TARBALL_INCLUDE
+    [--sync-delete]=SYNC_DELETE
+    [--no-sync-delete]=SYNC_DELETE
 )
 declare -Ar CLI_OPTION_ARGUMENT=(
     [--config]=path
+    [--sync-destination]=destination
 )
 
 usage() {
@@ -93,6 +103,7 @@ usage() {
     Usage:
     $0 --generate [--config PATH] [OPTIONS]
     $0 --refresh-splash [--config PATH] [OPTIONS]
+    $0 --sync [--config PATH] [OPTIONS]
     $0 --dry-run [--config PATH] [OPTIONS]
     $0 --print-config [--config PATH] [OPTIONS]
     $0 --clean [--config PATH] [OPTIONS]
@@ -116,6 +127,9 @@ usage() {
     --no-shuffle
     --tarball
     --no-tarball
+    --sync-destination DEST
+    --sync-delete
+    --no-sync-delete
     --verbose
     --quiet
 USAGE
@@ -407,6 +421,29 @@ resolve_tar_opts() {
     fi
 }
 
+resolve_sync_destinations() {
+    local -n destinations_ref="$1"; shift
+    local destinations_decl
+
+    destinations_ref=()
+
+    if ! destinations_decl=$(declare -p SYNC_DESTINATIONS 2>/dev/null); then
+        return
+    fi
+
+    case "$destinations_decl" in
+        declare\ -a*\ SYNC_DESTINATIONS=*)
+            destinations_ref=("${SYNC_DESTINATIONS[@]}")
+            ;;
+        *)
+            if [ -n "${SYNC_DESTINATIONS:-}" ]; then
+                # shellcheck disable=SC2034
+                read -r -a destinations_ref <<< "$SYNC_DESTINATIONS"
+            fi
+            ;;
+    esac
+}
+
 _html_escape() {
     local text="$1"; shift
 
@@ -2040,8 +2077,10 @@ print_shell_array_assignment() {
 
 print_config() {
     local -a tar_opts=()
+    local -a sync_destinations=()
 
     resolve_tar_opts tar_opts
+    resolve_sync_destinations sync_destinations
 
     print_shell_assignment CONFIG_SOURCE "${PHOTOALBUM_CONFIG_SOURCE:-}"
     print_shell_assignment INCOMING_DIR "$INCOMING_DIR"
@@ -2060,9 +2099,28 @@ print_config() {
     print_shell_assignment TARBALL_SUFFIX "${TARBALL_SUFFIX:-.tar}"
     print_shell_assignment TAR_TIMEOUT "$TAR_TIMEOUT"
     print_shell_array_assignment TAR_OPTS "${tar_opts[@]}"
+    print_shell_assignment SYNC_DELETE "${SYNC_DELETE:-yes}"
+    print_shell_array_assignment SYNC_DESTINATIONS "${sync_destinations[@]}"
     print_shell_assignment ORIGINAL_BASEPATH "${ORIGINAL_BASEPATH:-}"
 }
 
+sync_dist() {
+    local destination
+    local -a rsync_args=(-av)
+    local -a sync_destinations=()
+
+    resolve_sync_destinations sync_destinations
+
+    if [ "${SYNC_DELETE:-yes}" = yes ]; then
+        rsync_args+=(--delete)
+    fi
+
+    for destination in "${sync_destinations[@]}"; do
+        log_info "Syncing $DIST_DIR/ to $destination"
+        rsync "${rsync_args[@]}" "$DIST_DIR/" "$destination"
+    done
+}
+
 existing_parent_dir() {
     local -r path="$1"; shift
     local existing_parent
@@ -2256,12 +2314,16 @@ apply_config_defaults() {
     RANDOM_SEED="${RANDOM_SEED:-}"
     SHUFFLE="${SHUFFLE:-no}"
     SPLASH_PAGE="${SPLASH_PAGE:-yes}"
+    SYNC_DELETE="${SYNC_DELETE:-yes}"
     TARBALL_INCLUDE="${TARBALL_INCLUDE:-no}"
     TARBALL_SUFFIX="${TARBALL_SUFFIX:-.tar}"
     TAR_TIMEOUT="${TAR_TIMEOUT:-120}"
     if ! declare -p TAR_OPTS >/dev/null 2>&1; then
         TAR_OPTS=(-c)
     fi
+    if ! declare -p SYNC_DESTINATIONS >/dev/null 2>&1; then
+        SYNC_DESTINATIONS=()
+    fi
 }
 
 option_value() {
@@ -2291,6 +2353,10 @@ apply_cli_overrides() {
     for config_target in "${CLI_CONFIG_OVERRIDE_TARGETS[@]}"; do
         apply_cli_override "$config_target"
     done
+
+    if (( ${#cli_sync_destinations[@]} > 0 )); then
+        SYNC_DESTINATIONS=("${cli_sync_destinations[@]}")
+    fi
 }
 
 config_error() {
@@ -2493,9 +2559,42 @@ validate_generation_config() {
 
 validate_print_config() {
     local -a tar_opts=()
+    local -a sync_destinations=()
 
     validate_common_config
     resolve_tar_opts tar_opts
+    resolve_sync_destinations sync_destinations
+    validate_yes_no_config_var SYNC_DELETE
+}
+
+validate_sync_destinations() {
+    local -a sync_destinations=()
+
+    resolve_sync_destinations sync_destinations
+
+    if (( ${#sync_destinations[@]} == 0 )); then
+        config_error 'SYNC_DESTINATIONS must contain at least one destination'
+    fi
+}
+
+validate_rsync() {
+    if command -v rsync >/dev/null 2>&1; then
+        return
+    fi
+
+    config_error 'rsync is required to sync generated output'
+}
+
+validate_sync_config() {
+    require_config_var DIST_DIR
+    validate_yes_no_config_var SYNC_DELETE
+    validate_sync_destinations
+
+    if [[ ! -d "$DIST_DIR" || ! -r "$DIST_DIR" || ! -x "$DIST_DIR" ]]; then
+        config_error "DIST_DIR $DIST_DIR must be a readable directory"
+    fi
+
+    validate_rsync
 }
 
 set_cli_option_value() {
@@ -2503,6 +2602,12 @@ set_cli_option_value() {
     local -r value="$1"; shift
     local config_target
 
+    if [ "$option" = --sync-destination ]; then
+        cli_sync_destinations+=("$value")
+        has_config_overrides='yes'
+        return
+    fi
+
     config_target="${CLI_OPTION_CONFIG_TARGET[$option]:-}"
     if [ -n "$config_target" ]; then
         cli_overrides["$config_target"]="$value"
@@ -2622,6 +2727,7 @@ log_configured_action() {
     log_verbose "Effective tar timeout: ${TAR_TIMEOUT:-120}s"
     log_verbose "Effective splash page setting: ${SPLASH_PAGE:-yes}"
     log_verbose "Effective tarball setting: ${TARBALL_INCLUDE:-no}"
+    log_verbose "Effective sync delete setting: ${SYNC_DELETE:-yes}"
 }
 
 run_configured_action() {
@@ -2648,6 +2754,10 @@ run_configured_action() {
             validate_refresh_splash_config
             refresh_splash
             ;;
+        --sync)
+            validate_sync_config
+            sync_dist
+            ;;
         --dry-run)
             validate_generation_config no
             dry_run
@@ -2664,7 +2774,7 @@ run_action() {
         --version|--init)
             run_simple_action
             ;;
-        --clean|--generate|--refresh-splash|--dry-run|--print-config)
+        --clean|--generate|--refresh-splash|--sync|--dry-run|--print-config)
             run_configured_action
             ;;
         *)
@@ -2679,6 +2789,7 @@ main() {
     local config_file=''
     local has_config_overrides='no'
     local -A cli_overrides=()
+    local -a cli_sync_destinations=()
 
     if (( $# == 0 )); then
         usage
diff --git a/src/photoalbum.default.conf b/src/photoalbum.default.conf
index 6ce1f6d..6fad282 100644
--- a/src/photoalbum.default.conf
+++ b/src/photoalbum.default.conf
@@ -32,6 +32,15 @@ TARBALL_SUFFIX=.tar
 TAR_TIMEOUT=120
 TAR_OPTS=(-c)
 
+# Destinations for `photoalbum --sync`. Each destination is passed to rsync
+# with DIST_DIR/ as the source, so the generated contents are copied into the
+# target directory. Sync deletes removed files from destinations by default.
+SYNC_DELETE=yes
+SYNC_DESTINATIONS=(
+#    admin@fishfinger.buetow.org:/var/www/htdocs/example.org/
+#    admin@blowfish.buetow.org:/var/www/htdocs/example.org/
+)
+
 # Some debugging options
 #set -e
 #set -x
diff --git a/src/photoalbum.sh b/src/photoalbum.sh
index 0184a22..c215c01 100755
--- a/src/photoalbum.sh
+++ b/src/photoalbum.sh
@@ -23,6 +23,7 @@ declare -ra CLI_CONFIG_OVERRIDE_TARGETS=(
     RANDOM_SEED
     SHUFFLE
     SPLASH_PAGE
+    SYNC_DELETE
     TARBALL_INCLUDE
 )
 declare -Ar CLI_OPTION_KIND=(
@@ -42,6 +43,9 @@ declare -Ar CLI_OPTION_KIND=(
     [--no-splash]=flag
     [--tarball]=flag
     [--no-tarball]=flag
+    [--sync-delete]=flag
+    [--no-sync-delete]=flag
+    [--sync-destination]=value
     [--verbose]=output
     [--quiet]=output
     [--version]=action
@@ -49,6 +53,7 @@ declare -Ar CLI_OPTION_KIND=(
     [--clean]=action
     [--generate]=action
     [--refresh-splash]=action
+    [--sync]=action
     [--dry-run]=action
     [--print-config]=action
 )
@@ -64,6 +69,8 @@ declare -Ar CLI_OPTION_VALUE=(
     [--no-splash]=no
     [--tarball]=yes
     [--no-tarball]=no
+    [--sync-delete]=yes
+    [--no-sync-delete]=no
     [--verbose]=verbose
     [--quiet]=quiet
 )
@@ -83,9 +90,12 @@ declare -Ar CLI_OPTION_CONFIG_TARGET=(
     [--no-splash]=SPLASH_PAGE
     [--tarball]=TARBALL_INCLUDE
     [--no-tarball]=TARBALL_INCLUDE
+    [--sync-delete]=SYNC_DELETE
+    [--no-sync-delete]=SYNC_DELETE
 )
 declare -Ar CLI_OPTION_ARGUMENT=(
     [--config]=path
+    [--sync-destination]=destination
 )
 
 usage() {
@@ -93,6 +103,7 @@ usage() {
     Usage:
     $0 --generate [--config PATH] [OPTIONS]
     $0 --refresh-splash [--config PATH] [OPTIONS]
+    $0 --sync [--config PATH] [OPTIONS]
     $0 --dry-run [--config PATH] [OPTIONS]
     $0 --print-config [--config PATH] [OPTIONS]
     $0 --clean [--config PATH] [OPTIONS]
@@ -116,6 +127,9 @@ usage() {
     --no-shuffle
     --tarball
     --no-tarball
+    --sync-destination DEST
+    --sync-delete
+    --no-sync-delete
     --verbose
     --quiet
 USAGE
@@ -407,6 +421,29 @@ resolve_tar_opts() {
     fi
 }
 
+resolve_sync_destinations() {
+    local -n destinations_ref="$1"; shift
+    local destinations_decl
+
+    destinations_ref=()
+
+    if ! destinations_decl=$(declare -p SYNC_DESTINATIONS 2>/dev/null); then
+        return
+    fi
+
+    case "$destinations_decl" in
+        declare\ -a*\ SYNC_DESTINATIONS=*)
+            destinations_ref=("${SYNC_DESTINATIONS[@]}")
+            ;;
+        *)
+            if [ -n "${SYNC_DESTINATIONS:-}" ]; then
+                # shellcheck disable=SC2034
+                read -r -a destinations_ref <<< "$SYNC_DESTINATIONS"
+            fi
+            ;;
+    esac
+}
+
 _html_escape() {
     local text="$1"; shift
 
@@ -2040,8 +2077,10 @@ print_shell_array_assignment() {
 
 print_config() {
     local -a tar_opts=()
+    local -a sync_destinations=()
 
     resolve_tar_opts tar_opts
+    resolve_sync_destinations sync_destinations
 
     print_shell_assignment CONFIG_SOURCE "${PHOTOALBUM_CONFIG_SOURCE:-}"
     print_shell_assignment INCOMING_DIR "$INCOMING_DIR"
@@ -2060,9 +2099,28 @@ print_config() {
     print_shell_assignment TARBALL_SUFFIX "${TARBALL_SUFFIX:-.tar}"
     print_shell_assignment TAR_TIMEOUT "$TAR_TIMEOUT"
     print_shell_array_assignment TAR_OPTS "${tar_opts[@]}"
+    print_shell_assignment SYNC_DELETE "${SYNC_DELETE:-yes}"
+    print_shell_array_assignment SYNC_DESTINATIONS "${sync_destinations[@]}"
     print_shell_assignment ORIGINAL_BASEPATH "${ORIGINAL_BASEPATH:-}"
 }
 
+sync_dist() {
+    local destination
+    local -a rsync_args=(-av)
+    local -a sync_destinations=()
+
+    resolve_sync_destinations sync_destinations
+
+    if [ "${SYNC_DELETE:-yes}" = yes ]; then
+        rsync_args+=(--delete)
+    fi
+
+    for destination in "${sync_destinations[@]}"; do
+        log_info "Syncing $DIST_DIR/ to $destination"
+        rsync "${rsync_args[@]}" "$DIST_DIR/" "$destination"
+    done
+}
+
 existing_parent_dir() {
     local -r path="$1"; shift
     local existing_parent
@@ -2256,12 +2314,16 @@ apply_config_defaults() {
     RANDOM_SEED="${RANDOM_SEED:-}"
     SHUFFLE="${SHUFFLE:-no}"
     SPLASH_PAGE="${SPLASH_PAGE:-yes}"
+    SYNC_DELETE="${SYNC_DELETE:-yes}"
     TARBALL_INCLUDE="${TARBALL_INCLUDE:-no}"
     TARBALL_SUFFIX="${TARBALL_SUFFIX:-.tar}"
     TAR_TIMEOUT="${TAR_TIMEOUT:-120}"
     if ! declare -p TAR_OPTS >/dev/null 2>&1; then
         TAR_OPTS=(-c)
     fi
+    if ! declare -p SYNC_DESTINATIONS >/dev/null 2>&1; then
+        SYNC_DESTINATIONS=()
+    fi
 }
 
 option_value() {
@@ -2291,6 +2353,10 @@ apply_cli_overrides() {
     for config_target in "${CLI_CONFIG_OVERRIDE_TARGETS[@]}"; do
         apply_cli_override "$config_target"
     done
+
+    if (( ${#cli_sync_destinations[@]} > 0 )); then
+        SYNC_DESTINATIONS=("${cli_sync_destinations[@]}")
+    fi
 }
 
 config_error() {
@@ -2493,9 +2559,42 @@ validate_generation_config() {
 
 validate_print_config() {
     local -a tar_opts=()
+    local -a sync_destinations=()
 
     validate_common_config
     resolve_tar_opts tar_opts
+    resolve_sync_destinations sync_destinations
+    validate_yes_no_config_var SYNC_DELETE
+}
+
+validate_sync_destinations() {
+    local -a sync_destinations=()
+
+    resolve_sync_destinations sync_destinations
+
+    if (( ${#sync_destinations[@]} == 0 )); then
+        config_error 'SYNC_DESTINATIONS must contain at least one destination'
+    fi
+}
+
+validate_rsync() {
+    if command -v rsync >/dev/null 2>&1; then
+        return
+    fi
+
+    config_error 'rsync is required to sync generated output'
+}
+
+validate_sync_config() {
+    require_config_var DIST_DIR
+    validate_yes_no_config_var SYNC_DELETE
+    validate_sync_destinations
+
+    if [[ ! -d "$DIST_DIR" || ! -r "$DIST_DIR" || ! -x "$DIST_DIR" ]]; then
+        config_error "DIST_DIR $DIST_DIR must be a readable directory"
+    fi
+
+    validate_rsync
 }
 
 set_cli_option_value() {
@@ -2503,6 +2602,12 @@ set_cli_option_value() {
     local -r value="$1"; shift
     local config_target
 
+    if [ "$option" = --sync-destination ]; then
+        cli_sync_destinations+=("$value")
+        has_config_overrides='yes'
+        return
+    fi
+
     config_target="${CLI_OPTION_CONFIG_TARGET[$option]:-}"
     if [ -n "$config_target" ]; then
         cli_overrides["$config_target"]="$value"
@@ -2622,6 +2727,7 @@ log_configured_action() {
     log_verbose "Effective tar timeout: ${TAR_TIMEOUT:-120}s"
     log_verbose "Effective splash page setting: ${SPLASH_PAGE:-yes}"
     log_verbose "Effective tarball setting: ${TARBALL_INCLUDE:-no}"
+    log_verbose "Effective sync delete setting: ${SYNC_DELETE:-yes}"
 }
 
 run_configured_action() {
@@ -2648,6 +2754,10 @@ run_configured_action() {
             validate_refresh_splash_config
             refresh_splash
             ;;
+        --sync)
+            validate_sync_config
+            sync_dist
+            ;;
         --dry-run)
             validate_generation_config no
             dry_run
@@ -2664,7 +2774,7 @@ run_action() {
         --version|--init)
             run_simple_action
             ;;
-        --clean|--generate|--refresh-splash|--dry-run|--print-config)
+        --clean|--generate|--refresh-splash|--sync|--dry-run|--print-config)
             run_configured_action
             ;;
         *)
@@ -2679,6 +2789,7 @@ main() {
     local config_file=''
     local has_config_overrides='no'
     local -A cli_overrides=()
+    local -a cli_sync_destinations=()
 
     if (( $# == 0 )); then
         usage
diff --git a/tests/cli.sh b/tests/cli.sh
index d6e2787..905f6a4 100755
--- a/tests/cli.sh
+++ b/tests/cli.sh
@@ -1082,6 +1082,8 @@ TARBALL_INCLUDE=yes
 TARBALL_SUFFIX=.tar
 TAR_TIMEOUT=120
 TAR_OPTS=( -c )
+SYNC_DELETE=yes
+SYNC_DESTINATIONS=( )
 ORIGINAL_BASEPATH=''
 EOF
 )
@@ -1219,6 +1221,8 @@ TARBALL_INCLUDE=no
 TARBALL_SUFFIX=.tar
 TAR_TIMEOUT=120
 TAR_OPTS=( -c )
+SYNC_DELETE=yes
+SYNC_DESTINATIONS=( )
 ORIGINAL_BASEPATH=''
 EOF
 )
@@ -1258,6 +1262,8 @@ TARBALL_INCLUDE=no
 TARBALL_SUFFIX=.tar
 TAR_TIMEOUT=120
 TAR_OPTS=( -c )
+SYNC_DELETE=yes
+SYNC_DESTINATIONS=( )
 ORIGINAL_BASEPATH=''
 EOF
 )
@@ -1322,6 +1328,8 @@ TARBALL_INCLUDE=yes
 TARBALL_SUFFIX=.tar
 TAR_TIMEOUT=120
 TAR_OPTS=( -c )
+SYNC_DELETE=yes
+SYNC_DESTINATIONS=( )
 ORIGINAL_BASEPATH=''
 EOF
 )
@@ -3057,6 +3065,154 @@ test_generate_handles_space_and_underscore_names_distinctly() {
     test::teardown
 }
 
+test_sync_uses_config_destinations_with_delete() {
+    local config_file
+    local dist_dir
+    local fake_bin
+    local rsync_log
+    local rsync_output
+
+    test::setup
+    fake_bin="$TEST_TMPDIR/bin"
+    config_file="$TEST_TMPDIR/photoalbum.conf"
+    dist_dir="$TEST_TMPDIR/dist"
+    rsync_log="$TEST_TMPDIR/rsync.log"
+
+    test::install_rsync_spy "$fake_bin"
+    mkdir -p "$dist_dir"
+    printf 'generated\n' > "$dist_dir/index.html"
+    {
+        printf 'DIST_DIR=%q\n' "$dist_dir"
+        printf 'SYNC_DESTINATIONS=(\n'
+        printf '    %q\n' \
+            'admin@fishfinger.buetow.org:/var/www/htdocs/example.org/'
+        printf '    %q\n' \
+            'admin@blowfish.buetow.org:/var/www/htdocs/example.org/'
+        printf ')\n'
+    } > "$config_file"
+
+    (
+        cd "$TEST_TMPDIR"
+        PATH="$fake_bin:$PATH" TEST_RSYNC_LOG="$rsync_log" \
+            "$TEST_PHOTOALBUM" --sync
+    )
+
+    rsync_output=$(<"$rsync_log")
+    test::assert_contains $'argc=4\narg0=-av\narg1=--delete' \
+        "$rsync_output"
+    test::assert_contains "arg2=$dist_dir/" "$rsync_output"
+    test::assert_contains \
+        'arg3=admin@fishfinger.buetow.org:/var/www/htdocs/example.org/' \
+        "$rsync_output"
+    test::assert_contains \
+        'arg3=admin@blowfish.buetow.org:/var/www/htdocs/example.org/' \
+        "$rsync_output"
+    test::teardown
+}
+
+test_sync_cli_destinations_override_config_without_delete() {
+    local config_file
+    local dist_dir
+    local fake_bin
+    local rsync_log
+    local rsync_output
+
+    test::setup
+    fake_bin="$TEST_TMPDIR/bin"
+    config_file="$TEST_TMPDIR/photoalbum.conf"
+    dist_dir="$TEST_TMPDIR/dist"
+    rsync_log="$TEST_TMPDIR/rsync.log"
+
+    test::install_rsync_spy "$fake_bin"
+    mkdir -p "$dist_dir"
+    printf 'generated\n' > "$dist_dir/index.html"
+    {
+        printf 'DIST_DIR=%q\n' "$dist_dir"
+        printf 'SYNC_DESTINATIONS=(%q)\n' \
+            'admin@config.example:/var/www/config/'
+    } > "$config_file"
+
+    (
+        cd "$TEST_TMPDIR"
+        PATH="$fake_bin:$PATH" TEST_RSYNC_LOG="$rsync_log" \
+            "$TEST_PHOTOALBUM" \
+                --sync \
+                --no-sync-delete \
+                --sync-destination 'admin@one.example:/var/www/one/' \
+                --sync-destination 'admin@two.example:/var/www/two/'
+    )
+
+    rsync_output=$(<"$rsync_log")
+    test::assert_contains $'argc=3\narg0=-av' "$rsync_output"
+    test::assert_not_contains '--delete' "$rsync_output"
+    test::assert_not_contains 'admin@config.example' "$rsync_output"
+    test::assert_contains "arg1=$dist_dir/" "$rsync_output"
+    test::assert_contains 'arg2=admin@one.example:/var/www/one/' \
+        "$rsync_output"
+    test::assert_contains 'arg2=admin@two.example:/var/www/two/' \
+        "$rsync_output"
+    test::teardown
+}
+
+test_sync_rejects_empty_destinations() {
+    local config_file
+    local dist_dir
+    local fake_bin
+    local output
+    local rsync_log
+
+    test::setup
+    fake_bin="$TEST_TMPDIR/bin"
+    config_file="$TEST_TMPDIR/photoalbum.conf"
+    dist_dir="$TEST_TMPDIR/dist"
+    rsync_log="$TEST_TMPDIR/rsync.log"
+
+    test::install_rsync_spy "$fake_bin"
+    mkdir -p "$dist_dir"
+    printf 'DIST_DIR=%q\n' "$dist_dir" > "$config_file"
+
+    output=$(
+        cd "$TEST_TMPDIR"
+        PATH="$fake_bin:$PATH" TEST_RSYNC_LOG="$rsync_log" \
+            test::capture_failure_output "$TEST_PHOTOALBUM" --sync
+    )
+
+    test::assert_contains \
+        'ERROR: SYNC_DESTINATIONS must contain at least one destination' \
+        "$output"
+    test::assert_path_absent "$rsync_log"
+    test::teardown
+}
+
+test_sync_rejects_missing_dist() {
+    local config_file
+    local fake_bin
+    local output
+
+    test::setup
+    fake_bin="$TEST_TMPDIR/bin"
+    config_file="$TEST_TMPDIR/photoalbum.conf"
+
+    test::install_rsync_spy "$fake_bin"
+    {
+        printf 'DIST_DIR=%q\n' "$TEST_TMPDIR/missing-dist"
+        printf 'SYNC_DESTINATIONS=(%q)\n' \
+            'admin@example.org:/var/www/example.org/'
+    } > "$config_file"
+
+    output=$(
+        cd "$TEST_TMPDIR"
+        PATH="$fake_bin:$PATH" TEST_RSYNC_LOG="$TEST_TMPDIR/rsync.log" \
+            test::capture_failure_output "$TEST_PHOTOALBUM" --sync
+    )
+
+    test::assert_contains \
+        "ERROR: DIST_DIR $TEST_TMPDIR/missing-dist must be a readable directory" \
+        "$output"
+    test::assert_path_absent "$TEST_TMPDIR/rsync.log"
+    test::teardown
+}
+
 test_positional_commands_fail_without_deprecation() {
     local output
     local old_command
@@ -3113,6 +3269,7 @@ test_missing_option_values_fail() {
         --maxpreviews
         --image-jobs
         --random-seed
+        --sync-destination
     )
 
     for option in "${value_options[@]}"; do
@@ -3343,6 +3500,18 @@ main() {
         '--generate handles spaces and underscores distinctly' \
         test_generate_handles_space_and_underscore_names_distinctly
     test::run_case \
+        '--sync uses config destinations with delete' \
+        test_sync_uses_config_destinations_with_delete
+    test::run_case \
+        '--sync CLI destinations override config without delete' \
+        test_sync_cli_destinations_override_config_without_delete
+    test::run_case \
+        '--sync rejects empty destinations' \
+        test_sync_rejects_empty_destinations
+    test::run_case \
+        '--sync rejects missing dist' \
+        test_sync_rejects_missing_dist
+    test::run_case \
         'positional commands fail without deprecation output' \
         test_positional_commands_fail_without_deprecation
     test::run_case \
diff --git a/tests/helpers.sh b/tests/helpers.sh
index 6f6d507..155cfc0 100755
--- a/tests/helpers.sh
+++ b/tests/helpers.sh
@@ -479,6 +479,27 @@ TAR
     chmod 0755 "$bin_dir/tar"
 }
 
+test::install_rsync_spy() {
+    local -r bin_dir="$1"; shift
+
+    mkdir -p "$bin_dir"
+
+    cat > "$bin_dir/rsync" <<'RSYNC'
+#!/usr/bin/env bash
+set -euo pipefail
+
+{
+    printf 'argc=%s\n' "$#"
+    i=0
+    for arg in "$@"; do
+        printf 'arg%s=%q\n' "$i" "$arg"
+        i=$(( i + 1 ))
+    done
+} >> "$TEST_RSYNC_LOG"
+RSYNC
+    chmod 0755 "$bin_dir/rsync"
+}
+
 test::install_hanging_tar() {
     local -r bin_dir="$1"; shift