Add cronjob to rotate a symlink in logs directories.

opt/sbin/cronjob-rotate-logs-symlinks

@@ -0,0 +1,45 @@
+#!/bin/bash
+
+# Default configuration.
+LOGS_DIR="/var/log"
+DIR_MODE="0750"
+UMASK="027"
+
+# Allow /etc/default/rotate-logs-symlinks to override default configuration.
+[[ -e /etc/default/rotate-logs-symlinks ]] && {
+  # shellcheck disable=SC1091
+  source /etc/default/rotate-logs-symlinks || {
+    printf "%s: %s\\n" "${0##*/}" "failed reading /etc/default/rotate-logs-symlinks" >&2
+    exit 1
+  }
+}
+
+# Process the directories in the logs directory.
+[[ -d "$LOGS_DIR" ]] && {
+  TODAY="$(printf "%(%Y/%m/%d)T")"
+
+  umask "$UMASK"
+
+  # Process all the directories in the logs directory.
+  for DIR in "$LOGS_DIR"/*; do
+    cd "$DIR" 2>/dev/null || {
+      printf "%s: %s\\n" "${0##*/}" "failed to change directory to '$DIR'" >&2
+      continue
+    }
+
+    # Create a new logs directory for today.
+    # shellcheck disable=SC2174
+    mkdir -p -m "$DIR_MODE" "$TODAY" 2>/dev/null || {
+      printf "%s: %s\\n" "${0##*/}" "failed to create directory '$DIR/$TODAY'" >&2
+      continue
+    }
+
+    # Create a 'today' symlink to the new days' directory.
+    ( cd "$DIR" 2>/dev/null && ln -sf "$TODAY" "today" 2>/dev/null ) || {
+      printf "%s: %s\\n" "${0##*/}" "creating 'today' symlink failed" >&2
+      continue
+    }
+  done
+}
+
+exit 0