Bash Shell中命令行选项/参数处理

. / test.sh  - f config.conf  - v  -- prefix =/ home

1  # !/ bin / bash
 2  
 3  for  arg  in   " $* "
 4  do
 5      echo $arg
 6  done
 7  
 8  for  arg  in   " $@ "
 9  do
10      echo $arg
11  done
12

# !/ bin / bash

if  [ x$ 1   !=  x ]
then
    #...有参数
else
then
    #...没有参数
fi

#test.sh

# !/ bin / bash

while  getopts  " a:bc "  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 "
                ;;
             c)
                echo  " c "
                ;;
              ? )  #当有不认识的选项的时候arg为 ?
            echo  " unkonw argument "
        exit  1
        ;;
        esac
done

# !/ 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