select: move to common, fix placeholders (#12446)

pages/common/select.md

@@ -0,0 +1,20 @@
+# select
+
+> Bash builtin construct for creating menus.
+> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-select>.
+
+- Create a menu out of individual words:
+
+`select {{word}} in {{apple orange pear banana}}; do echo ${{word}}; done`
+
+- Create a menu from the output of another command:
+
+`select {{line}} in $({{command}}); do echo ${{line}}; done`
+
+- Specify the prompt string for `select` and create a menu for picking a file or folder from the current directory:
+
+`PS3="{{Select a file: }}"; select {{file}} in *; do echo ${{file}}; done`
+
+- Create a menu from a Bash array:
+
+`{{fruits}}=({{apple orange pear banana}}); select {{word}} in ${{{fruits[@]}}}; do echo ${{word}}; done`