sm: add page (#2529)

pages/linux/sm.md

@@ -0,0 +1,27 @@
+# sm
+
+> Displays a short message fullscreen.
+
+- Display a message fullscreen:
+
+`sm {{Hello World!}}`
+
+- Display a message with inverted colors:
+
+`sm -i {{Hello World!}}`
+
+- Display a message with a foreground color:
+
+`sm -f {{blue}} {{Hello World!}}`
+
+- Display a message with a background color:
+
+`sm -b {{#008888}} {{Hello World!}}`
+
+- Rotate the displayed message by n times 90 degrees:
+
+`sm -r {{3}} {{Hello World!}}`
+
+- Pipe a message to sm:
+
+`{{echo Hello World!}} | sm -`