预期脚本:从ifconfig解析ip地址

pb791b@pb791b-VirtualBox:~/devtest/ngs/base/Tests/shellScripts$ ifconfig enp0s3 | sed -n '/inet addr/s/.*addr.\([^ ]*\) .*/\1/p'
192.168.1.112

但当我在expect脚本中使用它时,它会出错。

#!/usr/bin/expect 

set pidBash [ spawn bash ]

set ipIfConfig {ifconfig enp0s3 | sed -n '/inet addr/s/.*addr.\([^ ]*\) .*/\1/p'}
set clientIP [exec "echo $ipIfConfig"]
puts "clientIP = $clientIP" 
exit 1

pb791b@pb791b-VirtualBox:~/devtest/ngs/base/Tests/shellScripts$ ./ifconfig_parse.sh 
spawn bash
couldn't execute "echo ifconfig enp0s3 | sed -n '/inet addr/s/.*addr.\([^ ]*\) .*/\1/p'": no such file or directory
    while executing
"exec "echo $ipIfConfig""
    invoked from within
"set clientIP [exec "echo $ipIfConfig"]"
    (file "./ifconfig_parse.sh" line 7)