1 files changed, 10 insertions, 0 deletions
diff --git a/watch-calendars b/watch-calendars
index cf9eb21..0c74f89 100755
--- a/watch-calendars
+++ b/watch-calendars
@@ -1,6 +1,16 @@
 #!/bin/bash
 
+lock_file=/tmp/watch-calendars.lock
+
 if [ $# -eq 0 ]; then
+  if [ -r "${lock_file}" ] \
+  && kill -0 "$(cat "${lock_file}")"; then
+    exit
+  fi
+
+  echo $$ >"${lock_file}"
+  trap 'rm "${lock_file:?}"' EXIT
+
   find ~/.local/share/khal/calendars \
     -mindepth 1 \
     -maxdepth 1 \