Telnetlib read_until() and expect() not detecting terminal echo

Question

I made a script in python that uses the telnetlib module for telnetting into a linux device, running an install.sh file, then rebooting upon completion. Upon completeion of the install.sh script, I added a line that sends echo "install complete" to the terminal. Unfortunately, read_until("install complete") and expect(["install complete"]) don't detect this echo.

tn = telnetlib.Telnet(ip)
tn.read_until("login: ")
tn.write(user + "\n")
tn.read_until("Password: ")
tn.write(password + "\n")
tn.write("cd [file path to the install script]")#echoes "install complete" when finished
tn.write("./install.sh\n")
tn.read_until("install complete")  #where the process hangs returns None if I add timeout parameter

Does telnetlib not reach echo statements or should I use another module or language? If I run the installer manually, I can confirm "install complete" echos as expected.

Answer 1

The code as shown doesn't include a newline ("\n") after the cd command, so the actual data sent appears likely to be "cd somepath./install.sh\n" which isn't going to work...

Also I'd avoid using the term "echo" here, since with telnet "echo" is really the part where the characters you send are sent back to you (for remote echo). In this case, whether that happens or not, the read_until() wouldn't care. In short, this isn't about echo at all.