Added mail server stuff

README.md

@@ -22,6 +22,8 @@
     * [OneDrive](./linux/onedrive.md)
 	* [Shell commands](./linux/shell_commands.md)
     * [udev](./linux/udev.md)
+* [Mail server](./mailserver/README.md)
+    * [Sieve](./mailserver/sieve.md)
 * [MySQL](./MySQL/README.md)
 * [ODroid](./odroid.md)
 * [OpenSSL](./OpenSSL.md)

mailserver/README.md

@@ -0,0 +1,3 @@
+# Mail server
+
+* [Sieve](./sieve.md)

mailserver/sieve.md

@@ -0,0 +1,19 @@
+# Sieve
+
+### Sieve rule to automatically sort mails by alias
+
+This Sieve rule filters mails by the mail alias they were sent to.
+Specifically, it uses a custom suffix separated by a dot: `.(.*)`
+It automatically creates a directory for that alias and moves the mail there.
+Then it stops processing.
+
+```
+require ["fileinto","regex","variables"];
+
+if allof (header :regex "to" "^<name>.(.*)@<domain.tld>$")
+{
+        set :lower :upperfirst "target" "${1}";
+        fileinto "${target}";
+        stop;
+}
+```