Question

shell 怎么实现lastindex

Answer 1

1.分析并执行如下代码
2.请分析代码的具体作用

#/bin/bash

#代码一
function changename() 一{

if [ -z $2 ];then
echo "lack function parameter "
return -1
fi
mv -f $1 $2
return 0
}
function change()
{
ofileName= # old file name
nfileName= #new file name
ls -l > a.txt
index=0
while read line
do
index=`expr ${index} + 1`
if [ ${index} -eq 1 ] ; then
continue; # ignore the first line of 'ls -l'
fi
a=($line)
#echo ${a[8]} the 9th element of array is file name
#echo ${a[3]} # the 3rd element of array is owner name
ofileName=${a[8]}
pos=`expr index ${ofileName} "."` # pos = the . position in file name
if [ ${pos} -eq 0 ] ; then 偿珐稗貉织股半瘫报凯 # if no . in file name then nfileName=oldName+[+owner+]
nfileName="${ofileName}[${a[3]}]"
else
owner="[${a[3]}]."
nfileName="${a[8]/./${owner}} " # substitute the . character to the "[owner]."
fi
echo "nfilename=${nfileName}"
changename ${ofileName} ${nfileName} #call function changename to change file name to new file name
done<a.txt
}

change
ls -l
echo "changed successfully"
错误提示是：
root@ubuntu:/opt/centralManage/shell# ls
sendPic.sh sendVid.sh work.sh
root@ubuntu:/opt/centralManage/shell# sh -x work.sh
+ ScriptSavePos=/opt/centralManage/shell/
+ configpath=/usr/local/bin/authentication
+ crontabfile=crontab.swap
+ read line
+ expr index authentication=0 =
+ len=15
work.sh: 15: work.sh: Bad substitution
root@ubuntu:/opt/centralManage/shell#

说15行有问题，但是周围几行分别是
14 len=`expr index "$line" =`
15 tmpStr=${line:0:len-1}
16 val=${line:len}
问题是：我./work.sh没什么问题啊，可以跑啊，但是sh -x work.sh就报错是为什么？求解答