Update cheatsheets

tldr/linux/ifstat

@@ -0,0 +1,21 @@
+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# ifstat
+
+> View network interface statistics.
+> More information: <https://manned.org/ifstat>.
+
+- View network interface statistics since last query:
+
+`ifstat`
+
+- View network interface statistics since last boot:
+
+`ifstat {{-a|--ignore}}`
+
+- View error rate:
+
+`ifstat {-e|--errors}}`