shell 中$0、$*、$#、$@ 之间的区别

shell 中$0、$*、$#、$@ 之间的区别

脚本示例

#!/bin/bash
MIN_PARAMS=10
echo
echo "The name of this script is \"`basename $0`\"."

echo
if [ -n "$1" ]; then
echo "param #1 is $1"
fi
if [ -n "$2" ]; then
echo "param #2 is $2"
fi
if [ -n "$3" ]; then
echo "param #3 is $3"
fi

echo "______________________________"
echo "All command-line params are : $*"
echo '$0 =' "$0"
echo '$# =' "$#"
echo '$@ =' "$@"
echo '$* =' "$*"

if [ $# -lt $MIN_PARAMS ]
then
echo
echo "this script need at least $MIN_PARAMS"
fi
exit 0

1. 终端直接执行 sh build-Test.sh

   The name of this script is "build-Test.sh".
   ______________________________
   All command-line params are : 
   $0 = build-Test.sh
   $# = 0
   $@ =
   $* = 
   
   this script need at least 1
   

   • $0直接，打印出脚本的名字build-Test.sh
   • 判断没有进入
   • $#的结果为0
   • $@、$*的结果为空

2. 终端直接执行 sh build-Test.sh 1

   The name of this script is "build-Test.sh".
   
   param #1 is 1
   ______________________________
   All command-line params are : 1
   $0 = build-Test.sh
   $# = 1
   $@ = 1
   $* = 1
   
   this script need at least 10
   

   • 判断已经执行
   • $# = 1，$@ = 1，$* = 1

3. 终端直接执行 sh build-Test.sh 1 2

   The name of this script is "build-Test.sh".
   
   param #1 is 1
   param #2 is 2
   ______________________________
   All command-line params are : 1 2
   $0 = build-Test.sh
   $# = 2
   $@ = 1 2
   $* = 1 2
   
   this script need at least 10
   

   • 判断已经执行
   • $# = 2，$@ = 1 2，$* = 1 2

4. 终端直接执行 sh build-Test.sh 1 2 3 4 5 6 7 8 9 10

   The name of this script is "build-Test.sh".
   
   param #1 is 1
   param #2 is 2
   param #3 is 3
   ______________________________
   All command-line params are : 1 2 3 4 5 6 7 8 9 10
   $0 = build-Test.sh
   $# = 10
   $@ = 1 2 3 4 5 6 7 8 9 10
   $* = 1 2 3 4 5 6 7 8 9 10
   

   • $0 可用来取出脚本的名字。
   • $# 代表参数的数量
   • $@和@* 可用来枚举出脚本的参数值
   • if [ -n "%1" ] 如果%1的长度非零则返回为真，即非空是真
   • [ INT1 -lt INT2 ] INT1小于INT2返回为真 ,<

shell 条件判断参考资料：http://blog.csdn.net/besfanfei/article/details/8259123