How to access environment variables in an Expect script?

问题

I would like to access the PATH environment variable inside an expect script.

How can I achieve that ?

My actual script is :

#!/usr/bin/expect
set timeout 300
send "echo $PATH\r"

and its ouput is :

can't read "PATH": no such variable
    while executing
"send "echo $PATH\r""

回答1:

Expect is an extension of Tcl. Tcl access enviroment variables via the global env array:

send_user "$env(PATH)\n"

回答2:

You can use the global env array by using:

$::env(PATH)    

This notion will also work inside procedures.

回答3:

If you want to read the target $PATH variable, then you must escape the "$" :

exp_sent -- echo "\$PATH\r"

来源：https://stackoverflow.com/questions/12695474/how-to-access-environment-variables-in-an-expect-script