Administrator@DADI ~ $ declare -i num=10 Administrator@DADI ~ $ echo $num 10 Administrator@DADI ~ $ num=‘iamaint‘ Administrator@DADI ~ $ echo $num 0
readonly OPTION VARIABLE(s)
Administrator@DADI ~ $ readonly MY_NAME=‘Administrator‘ Administrator@DADI ~ $ MY_NAME=‘ANOTHERNAME‘ -bash: MY_NAME: readonly variable Administrator@DADI ~ $ unset MY_NAME -bash: unset: MY_NAME: cannot unset: readonly variable
ARRAY=(value1 value2 ... valueN) ARRAY[0]="no.1 element"
myarray=(1 2 3 4 5 6 7 8)
echo ${myarray[0]}
myarray[0]="new value 1"echo ${#myarray[*]}不要和下面的搞混，只会返回myarray第一个元素的长度echo ${#myarray}echo ${myarray[*]}
for i in ${myarray[*]} ; do echo $i;done对于连续长度的也可以使用array_len=${#myarray[*]}
i=1
while [ $i -lt $array_len ]
do
echo ${myarray[$i]};
i=$[ $i + 1 ];
done
done;${VAR:OFFSET:LENGTH}Administrator@DADI ~
$ mystring="123456789"
Administrator@DADI ~
$
Administrator@DADI ~
$ echo ${mystring:2:2}
34
Administrator@DADI ~
$ echo ${mystring:2:4}
3456
${VAR/PATTERN/STRING}$ echo ${mystring/2/new2}
1new23456789
原文：http://blog.csdn.net/xfzheng_yeah/article/details/18792047