Initial data commit

Task/Optional-parameters/UNIX-Shell/optional-parameters.sh

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+# sort-args.sh
+
+data() {
+  cat <<EOF
+   123  456  0789
+   456 0789  123
+  0789  123  456
+EOF
+}
+
+# sort_table [column NUM | KIND | reverse] ... <INPUT >OUTPUT
+# KIND = lexicographical | numeric | human
+
+sort_table() {
+  local opts='-b'
+  local column=1
+  while (( $# > 0 )) ; do
+    case "$1" in
+      column|col|c)          column=${2?Missing column number} ; shift ;;
+      lexicographical|lex|l) opts+=' -d' ;;
+      numeric|num|n)         opts+=' -g' ;;
+      human|hum|h)           opts+=' -h' ;;
+      reverse|rev|r)         opts+=' -r' ;;
+    esac
+    shift
+  done
+  eval "sort $opts -k $column,$column -"
+}
+
+echo sort defaults          ; data | sort_table
+echo sort defaults reverse  ; data | sort_table reverse
+echo sort column 2          ; data | sort_table col 2
+echo sort column 2 reverse  ; data | sort_table col 2 reverse
+echo sort numeric           ; data | sort_table numeric
+echo sort numeric reverse   ; data | sort_table numeric reverse