REBIRTH

shell/options.md

@@ -0,0 +1,45 @@
+---
+title: Give shell script options
+tags: 
+- shell
+- script
+requires: shell/scripts.md
+---
+
+Place this in a file called `options.sh`, and make it executable.
+
+```sh
+#!/bin/sh
+
+echo "This script is called $0"
+
+while getopts oe: choice ; do
+    case "$choice" in
+        o)
+        echo "This is option number '${OPTIND}'."
+        ;;
+        e) echo "Option number '${OPTIND}' uses this variable: '${OPTARG}'."
+        ;;
+        \?) echo "That's not an option."
+        exit 1
+        ;;
+    esac
+done
+shift "$(($OPTIND -1))"
+
+echo "The standard arguments are: $@"
+```
+
+Try the options:
+
+
+```sh
+./options.sh -o
+./options.sh -e elephant
+./options.sh Some random words
+./options.sh -efox Some other words
+```
+
+Try the script again, without the `shift` statement.
+
+**NB:** You can change `choice` to any variable, but you must use `OPTARG` to show an option's argument and `OPTIND` to show the index of that argument.