collectd: add page (#3055)

pages/linux/collectd.md

@@ -0,0 +1,32 @@
+# collectd
+
+> System statistics collection daemon.
+> Homepage: <https://collectd.org/>.
+
+- Show usage help, including the program version:
+
+`collectd -h`
+
+- Test the configuration file and then exit:
+
+`collectd -t`
+
+- Test plugin data collection functionality and then exit:
+
+`collectd -T`
+
+- Start collectd:
+
+`collectd`
+
+- Specify a custom configuration file location:
+
+`collectd -C {{path/to/file}}`
+
+- Specify a custom PID file location:
+
+`collectd -P {{path/to/file}}`
+
+- Don't fork into the background:
+
+`collectd -f`