Shell脚本学习之基本参数
Shell脚本学习笔记---基本参数解析
常见命令行参数意义
菜鸟们总会被shell脚本中常见变量弄混淆，这些变量有$?, $#, $0, $@, $*
$?表示前一个命令的返回值，0表示正确，非0值表示错误
#test05.sh #!/bin/bash
sh test01.sh
if [ $? -ne 0 ]; then echo "test01.sh excute failed!" else echo "test01.sh excute right!" fi
#test01.sh
#!/bin/bash
array=(zl love ll forever)
for((i=0;i<${#array[@]};i++)); do
printf "%s " ${array[$i]}
done
printf "\n"
[[email protected] shell]$ sh test05.sh
zl love ll forever
test01.sh excute right!
$#表示命令行参数个数，相当于C语言中的argc
$0表示本脚本的名称
[[email protected] shell]$ vim test03.sh #!/bin/bash echo $0
结果如下
[[email protected] shell]$ sh test03.sh
test03.sh
所以$0参数还是很有用的，尤其在目录结构上，例如：
#!/bin/bash cd `dirname $0` source ../conf.sh
$@和$*都表示命令行参数，二者存在细微的区别：
共同之处：
echo "begin:"
for i in $@
do
echo $i
done;
result:
[[email protected] shell]$ sh test05.sh zl love ll 1314
begin:
zl
love
ll
1314
echo "begin:"
for i in $*
do
echo $i
done;
[[email protected] shell]$ sh test05.sh zl love ll 1314
begin:
zl
love
ll
1314
不同之处：
for i in "$@"
do
echo $i
done;
result:
[[email protected] shell]$ sh test05.sh zl love ll 1314
begin:
zl
love
ll
1314
echo "begin:"
for i in "$*"
do
echo $i
done;
[[email protected] shell]$ sh test05.sh zl love ll 1314
begin:
zl love ll 1314