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I am having issues with pexpect detecting "$" of the Linux command prompt. To give a better picture of what I am trying to accomplish:

Example Command Line prompt that I want to trigger my pexpect:

testcomp@testcomp-desktop:~$

Example of my pexpect code to detect it:

child.expect(['$',pexpect.TIMEOUT])

What results from this after testing it is that it chooses pexpect.TIMEOUT even though the prompt is there. I have also tried a couple of different variations of "$" like "\$" and "~$"

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  • @Asocia if you can't expect it then is there any way to verify that the command prompt is printed? Commented Jun 12, 2020 at 21:20
  • First: $ matches the end of a line when parsed as a regex; it doesn't match a dollar sign. [$] should work; whether \$ does depends on what kind of string you put it in. Commented Jun 12, 2020 at 22:26
  • Second: We really need a minimal reproducible example to know if the prompt should be seen. Please extend the code in your question to be a runnable example that should be able to match a prompt (maybe instantiate child by spawning something like bash -l -i) Commented Jun 12, 2020 at 22:27
  • @Charles Duffy, you were right the [$] expression does work. Thanks! Commented Jun 15, 2020 at 13:54

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FYI this is the code that should work if you want to do a console connection to a Linux machine (I was using minicom). What was described in the comments above was to use '[$]' to detect the Linux Command Line Prompt and it seemed to work well.

child = pexpect.spawn("minicom -b 115200 -o -D /dev/ttyUSB0") check = child.expect(["login",'[$]']) if(check == 0): child.sendline(username) child.sendline(password) else: child.sendline("\r")
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