Question

所以我一直在尝试用期望来学习bash脚本，并且我遇到了一个烦人的问题，即使在我通过将log_user设置为0来关闭输出之后，当我退出ssh服务器时的注销消息仍然打印为“登出与blah.blah.blah的连接关闭“。以hackish方式并在脚本中发出退出命令以期望是不可取的，并且忽略在终端中打印新行，留下难看的终端提示。我如何抑制或在我的expect脚本中关闭此连接已关闭的消息？这是我的expect脚本的代码模板：

#!/usr/bin/expect -f
#-f flag tells expect to read commands from file

# Set Password Prompt and Password
set PASSP "password:"
set PASSW "your_password_here\n"

# Set SFTP Prompt 
set SFTP "sftp> "

# Set Remote Prompt and Project Directories
# The GL server is super weird, so make sure RPROMPT ends in the
# name of the project compilation directory and PROJDIR is the 
# relative path (from home but without the tilde) of the main 
# project directory.

set RPROMPT "projdir_here]"
set PROJDIR "path_to_projdir_here"

# Set SSH Address
set ADDRESS your_username_here@your_address_here

# Annoying long output turned off
log_user 0

send_user "Logging in...\n"

spawn sftp $ADDRESS
expect $PASSP
send $PASSW

expect $SFTP
send_user "Uploading necessary files...\n"

send "cd $PROJDIR\n"
expect $SFTP
send "put *.cpp .\n"
expect $SFTP
send "put *.h .\n"
expect $SFTP
send "put Makefile .\n"
expect $SFTP
send "exit\n"

spawn ssh $ADDRESS
expect $PASSP
send $PASSW
expect "]"
send "cd $PROJDIR\n"

expect $RPROMPT
send_user "Cleaning remote directory...\n"

send "make clean\n"

# Output turned on temporarily so compiler feedback can be determined
expect $RPROMPT
log_user 1
send_user "Compiling on server...\n"

send "make\n"

# Turn off output and submit (this assumes that your makefile has a 'submit'
# target with the command to submit your file there)
expect $RPROMPT
log_user 0
send_user "\nSubmitting Requisite Files...\n"

send "make submit\n"

expect $RPROMPT
send_user "Quitting...\n"

# I can't figure out how to turn off stderr in expect so that an annoying 'connection closed' 
# message is printed even the log_user has been set to 0
send "logout\n"

# Transfer control to user
interact

您可以看到在程序结束时，在使用interact命令之前，在发送“logout \ n”并且关闭与服务器的连接之后打印出有问题的消息。尽管log_user设置为0，但仍会发生这种情况。我如何在脚本中关闭stderr输出？我甚至在expect man page查看了预期的手册页，但那里似乎没什么用处。我不明白如何关闭期望脚本中的stderr，以便不打印此消息，非常感谢帮助！我真的只是希望在我退出时脚本安静。因为很明显我发出了一个logout命令，所以我不确定为什么这个输出会转到stderr。在用户退出时，ssh中是否有一个命令不会输出“Connection to ... closed”消息？如果我能将stderr管道遗忘或以某种方式压制它会更好。正常的方式似乎不起作用，因为这是一个期望脚本。

Answer 1

这只是对log_user的错误使用。它应该用作，

log_user 0
send "logout\r"  
expect eof
log_user 1

请注意，我发送eof后期望logout\r模式，因为它会导致连接关闭。使用\r命令时，始终使用\n代替send。

阅读here以了解有关抑制输出的log_user的更多信息。

不是将提示定义为静态字符串，而是可以概括为

# We escaped the `$` symbol with backslash to match literal '$' 
# The last dollar sign represents line-end.
set prompt "#|>|%|\\\$ $";

在使用expect时，我们必须附带-re标志来指定它作为正则表达式。

expect -re $prompt

<强> SshDemo.exp

#!/usr/bin/expect 
set prompt "#|>|\\\$ $"
spawn ssh dinesh@myserver
expect {
        "(yes/no)" { send "yes\r";exp_continue}
        "password"
}
send "welcome123\r"
expect -re $prompt 
# Simply executing 'ls -l' command...
send "ls -l\r"
expect -re $prompt
log_user 0
send "logout\r"
expect eof
log_user 1

Answer 2

这是我基于上述建议的新改进脚本。我还决定使用scp而不是sftp，因为它更简洁，我只上传文件。

#!/usr/bin/expect -f
#-f flag tells expect to read commands from file

# Set Password Prompt and Password
set PASSP "password: "
set PASSW "your_password_here"

# Set Remote Prompt and Project Directories
# The ssh server is super weird, so make sure PROJDIR is the 
# directory name of the main project directory and PATH is
# the relative path to the project directory from home (with the tilde)

set PROJDIR "your_projdir_name_here"
set PATH "your_projdir_path_here"

# Set SSH Address
set ADDRESS your_username_here@source_hostname_here

# Turn off annoying output
log_user 0

send_user "Logging in and uploading necessary files...\n"

# upload files via scp, (shows upload prompt for user, concise)
spawn bash -c "scp *.cpp *.h Makefile $ADDRESS:$PATH"
expect $PASSP 
send "$PASSW\r"

interact

spawn ssh $ADDRESS
expect $PASSP
send "$PASSW\r"
expect "]"
send "cd $PATH\r"

expect "$PROJDIR]"
send_user "\nCleaning remote directory...\n"

send "make clean\r"

# Output turned on temporarily so compiler feedback can be determined
expect "$PROJDIR]"
log_user 1
send_user "Compiling on server...\n\n"

send "make\r"

# Turn off output and submit (this assumes that your makefile has a 'submit'
# target with the command to submit your file there)
expect "$PROJDIR]"
log_user 0
send_user "\n\nSubmitting Requisite Files...\n"

send "make submit\r"

expect "$PROJDIR]"
send_user "Quitting...\n"

send "logout\r"
expect eof

# Exit
exit

如何在Expect脚本中关闭stderr或退出后停止“连接到...关闭”消息？

2 个答案: