bash/shell 解析命令行参数工具：getopts/getopt

optionParam=$1
baseHdfsPath=$2
echo $optionParam|grep -qE '^(-d|-l)$' || usage
echo $baseHdfsPath|grep -qE '^/' || usage

if [[ $optionParam == "-l" ]]
then
	echo --------------------$startTime----------------------
	listDir "$baseHdfsPath"
	echo --------------------`date +'%F %T'`----------------------
else
	echo --------------------$startTime----------------------
	downLoadFiles "$baseHdfsPath"
	echo --------------------`date +'%F %T'`----------------------
fi

#!/bin/bash
while getopts 'd:Dm:f:t:' OPT; do
    case $OPT in
        d)
            DEL_DAYS="$OPTARG";;
        D)
            DEL_ORIGINAL='yes';;
        f)
            DIR_FROM="$OPTARG";;
        m)
            MAILDIR_NAME="$OPTARG";;
        t)
            DIR_TO="$OPTARG";;
        ?)
            echo "Usage: `basename $0` [options] filename"
    esac
done

shift $(($OPTIND - 1))

#!/bin/bash
echo 初始 OPTIND: $OPTIND

while getopts "a:b:c" arg #选项后面的冒号表示该选项需要参数
do
    case $arg in
        a)
			echo "a's arg:$OPTARG" #参数存在$OPTARG中
			;;
        b)
			echo "b's arg:$OPTARG"
			;;
        c)
			echo "c's arg:$OPTARG"
			;;
        ?)  #当有不认识的选项的时候arg为?
			echo "unkonw argument"
			exit 1
		;;
    esac
done

echo 处理完参数后的 OPTIND：$OPTIND
echo 移除已处理参数个数：$((OPTIND-1))
shift $((OPTIND-1))
echo 参数索引位置：$OPTIND
echo 准备处理余下的参数：
echo "Other Params: $@"

june@Win7 192.168.1.111 02:32:45 ~ >
bash b.sh -a 1 -b 2 -c 3  test -oo xx -test
初始 OPTIND: 1
a's arg:1
b's arg:2
c's arg:
处理完参数后的 OPTIND：6
移除已处理参数个数：5
参数索引位置：6
准备处理余下的参数：
Other Params: 3 test -oo xx -test
june@Win7 192.168.1.111 02:32:49 ~ >
bash b.sh -a 1 -c 3 -b 2 test -oo xx -test   # 非参数选项注意顺序与值，不要多传
初始 OPTIND: 1
a's arg:1
c's arg:
处理完参数后的 OPTIND：4
移除已处理参数个数：3
参数索引位置：4
准备处理余下的参数：
Other Params: 3 -b 2 test -oo xx -test
june@Win7 192.168.1.111 02:33:14 ~ >
bash b.sh -a 1 -c -b 2 test -oo xx -test
初始 OPTIND: 1
a's arg:1
c's arg:
b's arg:2
处理完参数后的 OPTIND：6
移除已处理参数个数：5
参数索引位置：6
准备处理余下的参数：
Other Params: test -oo xx -test
june@Win7 192.168.1.111 02:33:22 ~ >

Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->
#!/bin/bash

# A small example program for using the new getopt(1) program.
# This program will only work with bash(1)
# An similar program using the tcsh(1) script language can be found
# as parse.tcsh

# Example input and output (from the bash prompt):
# ./parse.bash -a par1 'another arg' --c-long 'wow!*?' -cmore -b " very long "
# Option a
# Option c, no argument
# Option c, argument `more'
# Option b, argument ` very long '
# Remaining arguments:
# --> `par1'
# --> `another arg'
# --> `wow!*?'

# Note that we use `"$@"' to let each command-line parameter expand to a
# separate word. The quotes around `$@' are essential!
# We need TEMP as the `eval set --' would nuke the return value of getopt.

#-o表示短选项，两个冒号表示该选项有一个可选参数，可选参数必须紧贴选项
#		如-carg 而不能是-c arg
#--long表示长选项
#"$@" ：参数本身的列表，也不包括命令本身
# -n:出错时的信息
# -- ：举一个例子比较好理解：
#我们要创建一个名字为 "-f"的目录你会怎么办？
# mkdir -f #不成功，因为-f会被mkdir当作选项来解析，这时就可以使用
# mkdir -- -f 这样-f就不会被作为选项。

TEMP=`getopt -o ab:c:: --long a-long,b-long:,c-long:: 
     -n 'example.bash' -- "$@"`

if [ $? != 0 ] ; then echo "Terminating..." >&2 ; exit 1 ; fi

# Note the quotes around `$TEMP': they are essential!
#set 会重新排列参数的顺序，也就是改变$1,$2...$n的值，这些值在getopt中重新排列过了
eval set -- "$TEMP"

#经过getopt的处理，下面处理具体选项。

while true ; do
    case "$1" in
        -a|--a-long) echo "Option a" ; shift ;;
        -b|--b-long) echo "Option b, argument `$2'" ; shift 2 ;;
        -c|--c-long)
            # c has an optional argument. As we are in quoted mode,
            # an empty parameter will be generated if its optional
            # argument is not found.
            case "$2" in
                "") echo "Option c, no argument"; shift 2 ;;
                *)  echo "Option c, argument `$2'" ; shift 2 ;;
            esac ;;
        --) shift ; break ;;
        *) echo "Internal error!" ; exit 1 ;;
    esac
done
echo "Remaining arguments:"
for arg do
   echo '--> '"`$arg'" ;
done