Unix commands(6)

                         echo "What is your favourite OS?"
                         select var in "Linux" "Gnu Hurd" "Free BSD" "Other"; do
　　　　                break
                                done
                           echo "You have selected ＄var"
　　            下面是该脚本运行的结果：
                               What is your favourite OS?
                                    1) Linux
                                    2) Gnu Hurd
                                    3) Free BSD
                                    4) Other
                                  #? 1
                                You have selected Linux
         注：var是个变量，可以换成其它的值。break用来跳出循环，如果没有break则一直循环下去。done与select对应。
                  4.loop
                      loop表达式：
                            while ...; do