Update cheatsheets

tldr/linux/head

@@ -8,6 +8,18 @@ source: https://github.com/tldr-pages/tldr.git
 > Output the first part of files.
 > More information: <https://www.gnu.org/software/coreutils/manual/html_node/head-invocation.html>.
 
+- Show first 10 lines in a file:
+
+`head {{path/to/file}}`
+
+- Show first 10 lines of multiple files:
+
+`head {{path/to/file1 path/to/file2 ...}}`
+
+- Output the first 5 lines of a file:
+
+`head {{[-5|--lines 5]}} {{path/to/file}}`
+
 - Output the first few lines of a file:
 
 `head {{[-n|--lines]}} {{count}} {{path/to/file}}`