I am trying to set up a expect script that logs in to a remote server and
fetches the 3 last created logfiles. The output (1 line) looks like below:
root#server1:/cluster/storage/var/log/alarms$
Last 3 created files are: FmAlarmLog_20180515_1.log FmAlarmLog_20180516_2.log FmAlarmLog_20180517_3.log
How can I split this output and create 3 different variables (one for each logfile) from this output?
The name of the logfiles always starts with "FmAlarmLog_"
I need to add later the part handling the fetching of those files.
#!/usr/bin/expect -f
set passwd "xxx"
set cmd1 "ls -ltr | tail -3 | awk '{print \$NF}'"
set dir "/cluster/storage/var/log/alarms"
set timeout 1
set prompt1 "*\$ "
log_user 0
spawn ssh admin#10.30.35.36
expect {
-re ".*Are.*.*yes.*no.*" {
send "yes\n"
exp_continue
}
"*?assword:*" {
send $passwd
send "\n"
}
}
expect $prompt1 { send "cd $dir\r"}
expect $prompt1 { send "$cmd1\r"}
set Last3LogFiles {}
expect \n
expect {
-re {^([^\r\n]*)\r\n} {
lappend Last3LogFiles $expect_out(1,string)
exp_continue
}
-ex $prompt1
}
send_user "Last 3 created files are: $Last3LogFiles\n"
send "exit\n"
exit 0
Try this:
expect $prompt1
send "$cmd1\r"
# express the prompt as a regular expression.
# best practice is to match the prompt at the end of the current input,
# I don't know if you have a space at the end of your prompt
expect -re {(.*)\r\n\$ ?$}
# command output is in $expect_out(1,string)
set Last3LogFiles [regexp -inline -all {FmAlarmLog_\S+} $expect_out(1,string)]
Related
I tried posting this in the codereview community, but there is no expect tag and I don't have enough karma to create tags.
I have written an expect script to either login to a server or run a simple (usually single) command and return the output.
I have two problems and a wish.
Commands that return nothing--i.e., ssh2server user host false--time out with an error (because I'm not capturing a timeout, though I suppose I should) instead of just returning nothing.
I can capture the return code of the program but I can't get it to exit with the appropriate code.
Is there a way I can take the output of the called program and return it the same way (remote stdout goes to local stdout and remote stderr goes to local stderr)?
Also, any comments or (constructive) criticisms would be appreciated.
#!/usr/bin/expect -f
if {[info exists ::env(SSH2SERVER_PASSWORD)]} {
set password "$env(SSH2SERVER_PASSWORD)"
} else {
puts "SSH2SERVER_PASSWORD not set"
exit 1
}
if {[llength $argv] < 2} {
puts "usage: ssh2server user server"
exit 1
}
set user [lindex $argv 0]
set server [lindex $argv 1]
set command [lrange $argv 2 end]
set pwd_prompt "*assword:"
set prompt "\$ "
set rc 0
expect_before {
#timeout { send_user 'timeout' ; exit 2 }
timeout { send_user 'timeout' ; set rc 2}
}
log_user 0
spawn ssh $user#$server
expect "$pwd_prompt" { send -- "$password\r" }
if { $command == "" } {
interact
} else {
expect {
"$prompt" {
send -- "PROMPT_COMMAND=\rPS1='_MYPROMPT_'\r$command\r"
#expect -re "$command\r\n(.*)\r\n\[^\r]*\[#\$%]"
expect -re "$command\r\n(.*)\r\n\[^\r]*_MYPROMPT_"
set results $expect_out(1,string)
puts $results
send -- "^D"
expect eof
#catch wait ec
#set rc [lindex $ec 3]
#puts [lindex $ec 3]
#exit [lindex $ec 3]
}
#eof { send_user $expect_out(buffer); exit 3}
eof { send_user $expect_out(buffer); set rc 3}
}
}
log_user 1
lassign [wait] pid spawnid os_flag rc
#puts $rc # outputs correct value
exit $rc
I suspect this is the problem:
send -- "^D"
You are not sending a Ctrl-D, you are sending the characters ^ and D.
To send a Ctrl-D
send -- "\04"
To solve the "no output, timeout" problem, you need to alter your expected regex: you have too many newlines for that case. Using expect -d would have revealed this to you. Like this:
send -- "unset PROMPT_COMMAND; PS1='_MYPROMPT_'\r"
expect -re "_MYPROMPT_$"
send -- "$command\r"
expect -re "$command(.*)\r\n_MYPROMPT_$"
The content of the capturing parentheses may now be empty.
I split off setting the prompt for clarity.
To capture the exit status of the command, you may have to do this:
send -- "$command; echo $?\r"
expect -re "$command(.*)\r\n(\d+)\r\n_MYPROMPT_$"
set results [regsub {^\r\n} $expect_out(1,string) ""]
set status $expect_out(2,string)
I don't think you can separate stdout and stderr with the expect command. I think both streams are captured as "output". (I don't have my Exploring Expect book nearby to confirm)
If that's important, you might want to invoke the command redirecting stdout and/or stderr to file(s), and then cat and capture the file contents.
I'm trying to write a shell function that spawns a ssh process and authentificates with a password. Then, I'd like to use the spawned process to do further stuff with expect.
Here's the function I have so far:
ssh_cmd() {
ssh $USER#$HOST 2>&1 | expect -c "
log_user 0
set timeout 5
expect password: {
send \"$PASS\n\"
sleep 2
log_user 1
}
"
}
And then I'd like to use given function in other places to interact with the ssh process like this:
ssh_cmd | expect -c "
expect '#' {
send pwd\n
send exit\n
}
expect eof
"
However, running the ssh_cmd function with -d option for expect I get the following result:
expect version 5.45.4
expect: does "" (spawn_id exp0) match glob pattern "password:"? no
ubnt#ui1's password: expect: timed out
From what I understand, the output of ssh does not get piped correctly. I know the common way to do this would be to use spawn, but that would mean the process would get killed after expect exits and I could not have a generic function that authentificates ssh sessions and keeps the process alive for further usage.
What you're designing won't work. Expect needs the process to be spawned from within the expect interpreter using the spawn command. Passing the command's stdout into expect is insufficient.
You could try this:
ssh_cmd() {
# a default bit of code if user does not provide one.
# you probably want some checking and emit an error message.
local user_code=${1:-set timeout 1; send "exit\r"; expect eof}
expect -c "
log_user 0
set timeout 5
spawn ssh -l $USER $HOST
expect password: {
send \"$PASS\n\"
sleep 2
log_user 1
}
$user_code
"
}
and then invoke it like:
ssh_cmd '
expect "#" {
send pwd\r
send exit\r
}
expect eof
'
Note that single quotes have no special meaning in expect, they are just plain characters: you probably don't want to expect the prompt to be the 3 character pattern '#'
I have make an example as below. The password（mingps）is the shell variable. When execute the shell script, in the mean while, execute command "ps -ef", I found the result of "ps" showed the password(mingps). For security reason, I don't want to show the password when execute command "ps -ef". So how to hide it? Thanks in advance.
#!/bin/sh
MalbanIP="XXX.XXX.XXX.XXX"
MalbanLogin="ming"
MalbanPwd="mingps"
MalbanCmd="netstat"
firstTime="true"
/usr/bin/expect <<EOF
set timeout 10
log_user 0
spawn /usr/bin/ssh $MalbanIP -l $MalbanLogin
expect {
-nocase "continue connecting (yes/no)?" {
send "yes\r"
expect "password:" {
send "$MalbanPwd\r"; set firstTime "false"; exp_continue
}
}
"password" {
if {$firstTime == "true"} {
send "$MalbanPwd\r"; set firstTime "false"
} else {
log_user 1; puts stdout "password is wrong"; log_user 0;
exit 1
}
}
}
expect "0-0-3"
log_user 1
send "$MalbanCmd \r"
set results \$expect_out(buffer)
expect "0-0-3" { send "exit\r" }
expect eof
EOF
exit 0
Option 1
The best way is to switch to using RSA keys to log in, as this will enable you to significantly strengthen your overall system security substantially. With that, you can probably avoid using Expect entirely.
Option 2
However, if you can't do that, the key to fixing things is to not pass it as either an argument or an environment variable (since ps can see both with the right options). Instead, you pass the password by writing it into a file and giving the name of that file to the Expect script. The file needs to be in a directory that only the current user can read; chmod go-rx will help there.
MalbanPwdFile=/home/malban/.securedDirectory/examplefile.txt
# Put this just before the spawn
set f [open $MalbanPwdFile]
set MalbanPwd [gets $f]
close $f
You might also need to put a backslash in front of the use of $MalbanPwd so that it doesn't get substituted by the shell script part too early.
Option 3
Or you could stop using that shell wrapper and do everything directly in Tcl/Expect.
#!/usr/bin/expect
set MalbanIP "XXX.XXX.XXX.XXX"
set MalbanLogin "ming"
set MalbanPwd "mingps"
set MalbanCmd "netstat"
set firstTime true
set timeout 10
log_user 0
spawn /usr/bin/ssh $MalbanIP -l $MalbanLogin
expect {
-nocase "continue connecting (yes/no)?" {
send "yes\r"
expect "password:" {
send "$MalbanPwd\r"
set firstTime false
exp_continue
}
}
"password" {
if {$firstTime} {
send "$MalbanPwd\r"
set firstTime false
} else {
log_user 1
puts stdout "password is wrong"
log_user 0
exit 1
}
}
}
expect "0-0-3"
log_user 1
send "$MalbanCmd \r"
set results \$expect_out(buffer)
expect "0-0-3" { send "exit\r" }
expect eof
I suspect that this last option will work best for you in the longer term. It's definitely the simplest one (other than switching to RSA keys, which is what I've got deployed on my own infrastructure) and I think it is going to avoid some subtle bugs that you've got in your current code (due to substitution of variables at the wrong time).
I wrote the following expect script:
set prompt {$}
set domain $::env(METEOR_DOMAIN)
puts "$domain"
spawn meteor mongo "$domain" --url
set pass "mypassword"
expect {
Password: {
send "$pass\r";
}
}
expect $prompt
puts "The output is '$expect_out(buffer)'."
and the puts command outputs:
The output is ' mypassword
mongodb://client:56099867-e806-3a7a-e5b4-93127e0a3b42#production-db-a1.meteor.io:27017/db_meteor_com'.
which I imagine is what is in the buffer, but I only want the second part (e.g.) the mongo string
How do I make expect only put the last part the buffer or only retrieve the last part in the buffer for storage in an environmental variable?
You can turn off stdout output before the password, and turn it back on afterward. Furthermore, you can parse the output and extract the mongo string. Here is one way to do it:
log_user 0
spawn ...
expect "Password:" {
send "mypassword\r"
}
log_user 1
...
if {[regexp -line {^mongodb:.*$} $expect_out(buffer) url]} {
set url [string trimright $url]
puts "URL is: '$url'"
}
According to the documentation, log_user 0 will turn off stdout, and log_user 1 will turn it back on.
I have a bash+expect script which has to connect via ssh to the remote comp (and i can't use ssh keys, need password identification in here), read the file there, find specific line with the "hostname" (like "hostname aaaa1111") and store this hostname into the variable to be used after while. How can i get the value of the "hostname" parameter? I thought that line content will be in $expect_out(buffer) variable (so i can scan it and analyze), but it's not. My script is:
#!/bin/bash
----bash part----
/usr/bin/expect << ENDOFEXPECT
spawn bash -c "ssh root#$IP"
expect "password:"
send "xxxx\r"
expect ":~#"
send "cat /etc/rc.d/rc.local |grep hostname \r"
expect ":~#"
set line $expect_out(buffer)
puts "line = $line, expect_out(buffer) = $expect_out(buffer)"
...more script...
ENDOFEXPECT
When i try to see line variable, i see only this: line = , expect_out(buffer) = (buffer) What is the right way to get the line from the file into the variable?
Or is it possible to open the file on the remote computer with expect, scan the file and get what i need to the variable?
Here http://en.wikipedia.org/wiki/Expect there is an example:
# Send the prebuilt command, and then wait for another shell prompt.
send "$my_command\r"
expect "%"
# Capture the results of the command into a variable. This can be displayed,
set results $expect_out(buffer)
seems that it doesn't work in this case?
You might just want to try and do it all from expect, as expect can control bash.
The following should do what you've described. Not sure if this is exactly what you are trying to do.
#!/bin/sh
# the next line restarts using tclsh \
exec expect "$0" "$#"
spawn bash
send "ssh root#$IP\r"
expect "password:"
send "xxxx\r"
expect ":~#"
send "cat /etc/rc.d/rc.local |grep hostname \n"
expect ":~#"
set extractedOutput $expect_out(buffer)
set list [split $extractedOutput "\n"]
foreach line $list {
set re {(?x)
.*
(*)
-S.*
}
regexp $re $line total extractedValue
if {[info exists extractedValue] && [string length $extractedValue] > 1} {
set exportValue $extractedValue
break # We've got a match!
}
send "exit\r" # disconnect from the ssh session
if {[info exists exportValue] && [string length $exportValue] > 1}{
send "export VARIABLE $exportValue\r"
} else {
send_user "No exportValue was found - exiting\n"
send "exit\r"
close
exit 1
}
# now you can do more things in bash if you like