셸 스 크 립 트 의 일부 매개 변수 처리

#!/bin/bash

echo $#

[root@redhat6 ~]# ./ts.sh para1
1
[root@redhat6 ~]# ./ts.sh para1 para2
2
[root@redhat6 ~]# ./ts.sh para1 para2 para3
3
[root@redhat6 ~]# ./ts.sh para1 para2 para3 para4
4
[root@redhat6 ~]# ./ts.sh para1 para2 para3 para4 para5
5

  ：$0     ，     ， $1    。

if [ $# -eq 0 ];
then
    usage
    exit
fi

#!/bin/bash

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

1. $#           
2. $*                    。       ，        9 
3. $$          ID 
4. $!               ID 
5. $@  $#  ，        ，           
6. $-   shell       ， set      
7. $?            。0      ，          。

$0      
$1      #1 
$2 - $9      #2 - #9 
${10}      #10 
$#         
"$*"        (       ) * 
"$@"        (           ) 
${#*}                 
${#@}                 
$?     
$$      ID(PID) 
$-          (  set) 
$_             
$!                ID(PID)

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

*       
* getopts
* getopt

 $0 ： ./test.sh,     ，   C/C++  argv[0]
 $1 ： -f,     .
 $2 ： config.conf
 $3, $4 ... ：  。
 $#      ，       ，   $# 4.
 $@ ：       ，        ，     -f config.conf -v --prefix=/home
 $* ： $@  ， "$*"   "$@"(   )   ，"$*"              ， "$@"       。

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

  ./test.sh -f config.conf -n 10    ：
-f config.conf -n 10    #  "$*"   
-f   #   $@   
config.conf
-n
10

./test.sh 10

#!/bin/bash

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

if [ -n $1 ] #$1   

./test.sh -a -b -c ：    ，       
./test.sh -abc   ：    ，           ，            。
./test.sh -a args -b -c ：   ，  -a    ， -b -c    。
./test.sh --a-long=args --b-long ：   

#test.sh

#!/bin/bash

while getopts "a:bc" arg #                
do
        case $arg in
             a)
                echo "a's arg:$OPTARG" #    $OPTARG 
                ;;
             b)
                echo "b"
                ;;
             c)
                echo "c"
                ;;
             ?) #           arg ?
            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     ，                ，          
# -carg     -c arg
#--long     
#"$@"      
# -n:      

mkdir -f #   ，  -f  mkdir       ，       
mkdir -- -f   -f        。
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           ，     $1,$2...$n  ，    getopt       
eval set -- "$TEMP"

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

MYFILE="cat myfile" 
echo $MYFILE   # output: cat myfile 
eval $MYFILE   # output: contents of myfile

#!/bin/bash 
# evalit 
echo " Total number of arguments passed: $#" 
echo " The process ID: $$" 
echo " Last argument: " $(eval echo /$$#) 
    ： 
$ ./evalit alpha bravo charlie 
output as follows: 
Total number of arguments passed: 3 
The process ID: 780 
Last argument:   charlie

    
for i in `cat abc.txt`
do
echo $i
done