Shell编程之 函数

1、无参函数语法:

functionName(){
    commands;
}
获取当前系统时间的函数

#!/bin/bash
#Get current date


getCurrentDate(){
    current_date=`date --date="now" +%Y-%m-%d' '%H:%M:%S`;
    cur_time=`date "+%Y-%m-%d %H:%M:%S"`;
    echo $cur_time;
    echo $current_date;
}


getCurrentDate

Notes：
1. 函数调用
直接使用函数名，如：getCurrentDate
2. 返回值
使用 echo，如：cur_time 和 current_date


2、有参函数语法:

functionName(){
    arg1=$1;
    arg2=$2;
    arg3=0;
    commands;

}

#!/bin/bash
#Fibonacci Sequence

echo "Press a number here..."
read number

if [ $number -le 0 ]
then
   echo "You have something wrong.The number must be great then 0."
   exit 1
fi
echo "Well, you wanna print between 1 and $number, and count them."

fibonacci(){
  arg1=0
  arg2=1
  for((i=1;i<=$number;i++))
  do
    ((arg3=$arg1+$arg2))

    echo "Seq: $arg1+$arg2=$(($arg1+$arg2))"

    sum=$(($sum+$arg3))
    arg1=$arg2
    arg2=$arg3
  done

  echo "$sum"
}
fibonacci