How to access environment variables in an Expect script?

Question

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""

Very nuanced issue. I struggled with it for many hours. Thanks for asking the right questions. — magnus167, Dec 01 '22 at 22:50

score 68 · Accepted Answer · answered Oct 02 '12 at 22:06

68

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

send_user "$env(PATH)\n"

answered Oct 02 '12 at 22:06

glenn jackman

238,783
38
220
352

score 17 · Answer 2 · answered Jan 22 '14 at 14:02

17

You can use the global env array by using:

$::env(PATH)

This notion will also work inside procedures.

answered Jan 22 '14 at 14:02

Timmah

2,001
19
18

This should be approved as the correct answer, it works – Igor Leonovich Aug 01 '23 at 21:00

score 2 · Answer 3 · answered Aug 26 '13 at 10:04

2

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

exp_sent -- echo "\$PATH\r"

answered Aug 26 '13 at 10:04

akiuni

17
1

score 1 · Answer 4 · answered Jan 01 '22 at 11:22

1

Both $::env(PATH) and $env(PATH) work well. The former is ok also inside other scripts (like expect -c "...", the latter is more "programming style".

answered Jan 01 '22 at 11:22

ghillo

31
1

How to access environment variables in an Expect script?

4 Answers4

Linked