Update cheatsheets

tldr/nice

@@ -7,12 +7,25 @@ source: https://github.com/tldr-pages/tldr.git
 
 > Execute a program with a custom scheduling priority (niceness).
 > Niceness values range from -20 (the highest priority) to 19 (the lowest).
+> Note: Some modern schedulers ignore niceness or limit its effects inside autogroups.
 > More information: <https://www.gnu.org/software/coreutils/manual/html_node/nice-invocation.html>.
 
-- Launch a program with altered priority:
+- Print the current niceness value:
+
+`nice`
+
+- Increment the current niceness value by 10:
+
+`nice nice`
+
+- Launch a program with lowered priority:
 
 `nice -{{niceness_value}} {{command}}`
 
+- Launch a program with heightened priority:
+
+`sudo nice --{{niceness_value}} {{command}}`
+
 - Define the priority with an explicit option:
 
 `nice {{[-n|--adjustment]}} {{niceness_value}} {{command}}`