shell腳本讀取命令行參數的實現

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

#!/bin/bash
for arg in "$*"
  do
    echo $arg
  done
for arg in "$@"
  do
    echo $arg
  done

./test.sh 10

#!/bin/bash
if [ x$1 != x ]
then
  #...有參數邏輯
else
then
  #...沒有參數邏輯
fi

if [ -n $1 ]  #$1不為空

#test.sh
#!/bin/bash
while getopts "a:bc" arg #選項後面的冒號表示該選項需要參數
do
        case $arg in
             a)
                echo "a's arg:$optarg" #參數存在$optarg中

             b)
                echo "b"

             c)
                echo "c"

             ?)  #當有不認識的選項的時候arg為?
            echo "unkonw argument"
        exit 1

        esac
done

./test.sh -a arg -b -c

./test.sh -a arg -bc

#!/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表示短選項，兩個冒號表示該選項有一個可選參數，可選參數必須緊貼選項
#如-carg 而不能是-c arg
#--long表示長選項
#"$@"在上面解釋過
# -n:出錯時的信息
# -- ：舉一個例子比較好理解：
#我們要創建一個名字為 "-f"的目錄你會怎麼辦？
# mkdir -f #不成功，因為-f會被mkdir當作選項來解析，這時就可以使用
# mkdir -- -f 這樣-f就不會被作為選項。
temp=`getopt -o ab:c:: --long a-long,b-long:,c-long:: \
     -n 'example.bash' -- "$@"`
if [ $? != 0 ] ; then echo "terminating..." >&2 ; exit 1 ; fi
# note the quotes around `$temp': they are essential!
#set 會重新排列參數的順序，也就是改變$1,$2...$n的值，這些值在getopt中重新排列過瞭
eval set -- "$temp"
#經過getopt的處理，下面處理具體選項。
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

./test -a -b arg arg1 -c

-a -b arg -c -- arg1