linux文档中option指的是什么

*    $0 ：即命令本身，相当于c/c++中的argv[0]  
*    $1 ：第一个参数.  
*    $2, $3, $4 ... ：第2、3、4个参数，依次类推。  
*    $#  参数的个数，不包括命令本身  
*    $@ ：参数本身的列表，也不包括命令本身  
*    $* ：和$@相同，但"$*" 和 "$@"(加引号)并不同，"$*"将所有的参数解释成一个字符串，而"$@"

#!/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

./getargs.sh 11 22 cc  
commond is ./getargs.sh  
args are:  
11  22  cc

[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

./getopt.sh --b-long abc -a -c33 remain  
option b, argument `abc'  
option a  
option c, argument `33'  
remaining arguments:  
--> `remain'