#!/bin/bash
if [ $# -lt 1 ]; then  echo "error.. need args"  exit 1
fi
echo "commond is $0"
echo "args are:"
for arg in "$@"
do  echo $arg
done  

[root@jbxue ~]$ type getopt
getopt is /usr/bin/getopt
[root@jbxue ~]$ type getopts
getopts is a shell builtin  

echo $*
while getopts ":a:bc" opt
do  case $opt in  a ) echo $optarg  echo $optind;;  b ) echo "b $optind";;  c ) echo "c $optind";;  ? ) echo "error"  exit 1;;  esac
done
echo $optind
shift $(($optind - 1))
#通过shift $(($optind - 1))的处理，$*中就只保留了除去选项内容的参数，可以在其后进行正常的shell  编程处理了。
echo $0
echo $*  

./getopts.sh -a 11 -b -c
-a 11 -b -c
11
3
b 4
c 5
5
./getopts.sh  

#!/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
#"$@"在上面解释过
# -n:出错时的信息
# -- ：举一个例子比较好理解：
#我们要创建一个名字为 "-f"的目录你会怎么办？
# mkdir -f #不成功，因为-f会被mkdir当作选项来解析，这时就可以使用
# mkdir -- -f 这样-f就不会被作为选项。
temp=`getopt -o ab:c:: --long a-long,b-long:,c-long:: \  -n 'example.bash' -- "$@"`
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