diff --git a/README.md b/README.md
index 15c08f4..f437635 100644
--- a/README.md
+++ b/README.md
@@ -129,6 +129,17 @@ Non-TPDU messages (ATR, PPS, card state changes, Fi/Di) print identically in all
 - **GSMTAP**: ATR (subtype 1) and TPDU (subtype 2) over UDP to Wireshark
 - **PCAP**: all messages as GSMTAP-encapsulated packets (LINKTYPE 155), openable in Wireshark
 
+## Background / Daemon
+
+SIGHUP is ignored by default — terminal closure won't kill the sniffer.
+To run persistently in the background with output to files:
+
+```sh
+nohup ./sniff-start.sh --output /tmp/sniff.log &> /tmp/sniff-err.log &
+# or
+FORMAT=timestamp nohup python -m simtrace2_pysniff --output /tmp/sniff.log &> /tmp/sniff-err.log &
+```
+
 ## Library Usage
 
 ```python
diff --git a/simtrace2_pysniff/__main__.py b/simtrace2_pysniff/__main__.py
index 5235774..4b49d82 100644
--- a/simtrace2_pysniff/__main__.py
+++ b/simtrace2_pysniff/__main__.py
@@ -131,6 +131,7 @@ def main():
             file_dumper.close()
         sys.exit(0)
 
+    signal.signal(signal.SIGHUP, signal.SIG_IGN)
     signal.signal(signal.SIGINT, on_signal)
     signal.signal(signal.SIGTERM, on_signal)