Logtail安装失败

安装的时候显示这个错误， ./logtail.sh: 82: ./logtail.sh: Bad substitution

我的服务器是 非本人ECS或线下机器，已经按要求建立了文件 touch /etc/ilogtail/users/1008072200622279

以下是完整错误日志

root@www:~# wget http://logtail-release-us-west-1.oss-us-west-1.aliyuncs.com/linux64/logtail.sh -O logtail.sh; chmod 755 logtail.sh; ./logtail.sh install us-west-1_internet
--2018-08-17 08:39:38--  http://logtail-release-us-west-1.oss-us-west-1.aliyuncs.com/linux64/logtail.sh
Resolving logtail-release-us-west-1.oss-us-west-1.aliyuncs.com (logtail-release-us-west-1.oss-us-west-1.aliyuncs.com)... 47.89.226.47
Connecting to logtail-release-us-west-1.oss-us-west-1.aliyuncs.com (logtail-release-us-west-1.oss-us-west-1.aliyuncs.com)|47.89.226.47|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 13601 (13K) [application/x-sh]
Saving to: ‘logtail.sh’

logtail.sh                          100%[===================================================================>]  13.28K  --.-KB/s    in 0s

2018-08-17 08:39:38 (130 MB/s) - ‘logtail.sh’ saved [13601/13601]

logtail.sh version: 1.3.0

-e OS Arch:     x86_64
-e OS Distribution:     Ubuntu
update-rc.d del ilogtaild success
uninstall logtail success
./logtail.sh: 82: ./logtail.sh: Bad substitution