Expect doesn't execute script in screen

Question

I'm trying to execute a script in screen through expect with ssh, but it's never executed. I know this because I do not see a screen session with screen -list. Expects' exit code is 0. If I execute the command through SSH manually, it works.

What am I doing wrong? (Other ways to achieve my goal are welcome as well).

The script:

#! /bin/bash
expect -d <<-EOF
    set timeout -1
    spawn ssh ${user}@${host}
    expect {
        "yes/no" { send "yes\r"; exp_continue }
        "password: " { send "${pass}\r" }
    }
    expect "*# "
    send "screen -dm bash -c './${CLIENT_SCRIPT_LOG}'\r"
    exit 0
EOF
exit $?

Debug output:

[.. cut ..]
expect: set expect_out(buffer) "\r\nLinux client 4.9.76-Rxx-rt61-gb7ccafd-dirty #1 SMP PREEMPT RT Wed Apr 1 13:14:00 CEST 2020 armv7l\r\n\r\nThe programs included with the Debian GLinux system are free software;\r\nthe exact distribution terms for each program are described in the\r\nindividual files in /usr/share/doc/*/copyright.\r\n\r\nDebian GNU/Linux cs with ABSOLUTELY NO WARRANTY, to the extent\r\npermitted by applicable law.\r\nLast login: Thu Jan  1 05:29:03 1970 from 192.168.138.2\r\r\nroot@client:~# "
send: sending "screen -dm bash -c './log.sh'\r" to { exp5 }

Versions client:
- Debian Wheezy
- Bash 4.2.37
- Screen 4.01.00devel

Versions host:
- Debian Stretch
- Bash 4.4.12(1)-release
- Screen version 4.05.0
- Expect 5.45

Take a look at my [sexpect (Expect for Shells)](https://github.com/clarkwang/sexpect) which you can use to write Expect scripts with **shell code only**. — sexpect - Expect for Shells, May 16 '20 at 14:05

score 1 · Accepted Answer · answered May 15 '20 at 21:08

1

Alright, it seems that I have to wait until the command is executed and exit the terminal. I think expect is too fast otherwise.

send "screen -dm bash -c './${CLIENT_SCRIPT_LOG}'\r"
expect "*# " { send "exit\r" }
exit 0

answered May 15 '20 at 21:08

Bayou

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1

I'd recommend your last line be `expect eof` to allow ssh to exit gracefully. – glenn jackman May 16 '20 at 21:12

Expect doesn't execute script in screen

1 Answers1