I am able to open a spawned telnet session in a shell script to run some commands. Afterwards, I am trying to send the escape character using send (see syntax below) but it never gets to the part where I am able to close the session. Can someone point me in the right direction? Due to this issue, I am opening up multiple telnet sessions this way, which I do not want to do.
send "^]\r"
expect "telnet>"
send "close\r"
close $spawn_id
You send the ESC control sequence. Try send "\x1b\r"
I was trying to solve this question since the past couple of days and finally found a solution :)
The \x1b\r and \x1d\r did not work for me. I found the solution here:Using Control character in a script with tr and echo
I used the following code:
escseq=`echo 'e' | tr 'e' '\035'`
Use $escseq to get Ctrl+].
How this works:
If your echo can't make control characters directly, the tr utility can do it for you. tr understands octal sequences, too. Make your echo output characters you don't want, and have tr translate them into the control characters you do want.
For example, to make the 4-character sequence ESCape CTRL-a [ CTRL-w , use a command like this:
escseq=`echo 'ea[w' | tr 'eaw' '\033\001\027'`
tr reads the four characters down the pipe from echo ; it translates the e into ESCape (octal 033), the a into CTRL-a (octal 001), and the w into CTRL-w (octal 027). The left bracket isn't changed; tr prints it as is.
Note: This is extremely useful if you want to automate logout of a telnet session using a shell script.
CTRL+R represents the "^]" escape sequence to get out of telnet
Related
I have a program read from stdin and process it. ( like "tee /some/file" )
This program wait stdin end to exit itself.
If I spawn it from Expect, after I send many content, how to send an "EOF" to the program?
there is a close command in Expect, but it will also send a SIGHUP, and can not expect program output anymore.
Expect works (on non-Windows) by using a virtual terminal which the spawned program runs within. This means that you can do things by sending character sequences to simulate keys. In particular, the EOF control sequence is done with Ctrl+D, which becomes the character U+000004. The terminal processes this to turn it into a true EOF.
There's a few ways to write it, depending on which escape sequence you prefer, but one of these will work:
# Hexadecimal-encoded escape
send \x04
# Octal-encoded escape
send \004
# UNICODE escape (also hexadecimal)
send \u0004
# Generate by a command
send [format "%c" 4]
When Expect is using Tcl 8.6, these all generate the same bytecode so use whichever you prefer.
I am trying to port my first app I ever wrote from old Borland Pascal to FreePascal and run it in Linux unicode shell.
Unfortunately, the app uses CRT unit and writes non-standard ASCII graphical characters. So I tried to rewrite statements like these:
gotoxy(2,3); write(#204);
writeln('3. Intro');
to these:
gotoxy(2,3); write('╠');
write('3. Intro', #10);
Two notes:
I use unicode characters directly in code because I did not find out how to write unicode characters via their code.
I used write procedure instead of writeln to make sure that unix line endings will be produced.
But after replacing all non-standard ASCII characters and getting rid of all writeln statements, it became even worse.
Before changes:
After changes:
Why it ends up like this? What I can do better?
After some time here is an update what I found out.
1) I cannot port it
As user #dmsc rightly pointed out, CRT does not support UTF-8. His suggested hack that did not work for me.
2) When you can't port it, emulate environment.
The graphical characters I needed were part of CP-437. There is a program called luit that is made for converting application output from the locale's encoding into UTF-8. Unfortunately this does not work for me. It simple erased the characters:
# Via iconv, everything is OK:
$ printf "top right corner in CP437: \xbf \n" | iconv -f CP437 -t UTF-8
top right corner in CP437: ┐
# But not via luit, that simply omit the character:
$ luit -gr g2 -g2 'CP 437' printf "top right corner in CP437: \xbf \n"
top right corner in CP437:
So my solution is to run gnome-terminal, add and set Hebrew (IBM862) encoding (tutorial here) and enjoy your app!
The CRT unit does not currently works with UTF-8, as it assumes that each character on the screen is exactly one byte, see http://www.freepascal.org/docs-html-3.0.0/rtl/crt/index.html
But, simple applications can be made to work by "tricking" GotoXY to always do a full cursor positioning, by doing:
GotoXY(1,1);
GotoXY(x, y);
To replace all the strings in your source file, you can use recode, in a terminal type:
recode cp437..u8 < original.pas > fixed.pas
Then, you need to replace all the numeric characters (like your #204 example) with the equivalent UTF-8, you can use:
echo -e '\xCC' | recode cp437/..u8
The 'CC' is hexadecimal for 204, and as a result the character '╠' will be printed.
I am navigating a Java-based CLI menu on a remote machine with expect inside a bash script and I am trying to extract something from the output without leaving the expect session.
Expect command in my script is:
expect -c "
spawn ssh user#host
expect \"#\"
send \"java cli menu command here\r\"
expect \"java cli prompt\"
send \"java menu command\"
"
###I want to extract a specific string from the above output###
Expect output is:
Id Name
-------------------
abcd 12 John Smith
I want to extract abcd 12 from the above output into another expect variable for further use within the expect script. So that's the 3rd line, first field by using a double-space delimiter. The awk equivalent would be: awk -F ' ' 'NR==3 {$1}'
The big issue is that the environment through which I am navigating with Expect is, as I stated above, a Java CLI based menu so I can't just use awk or anything else that would be available from a bash shell.
Getting out from the Java menu, processing the output and then getting in again is not an option as the login process lasts for 15 seconds so I need to remain inside and extract what I need from the output using expect internal commands only.
You can use regexp in expect itself directly with the use of -re flag. Thanks to Donal on pointing out the single quote and double quote issues. I have given solution using both ways.
I have created a file with the content as follows,
Id Name
-------------------
abcd 12 John Smith
This is nothing but your java program's console output. I have tested this in my system with this. i.e. I just simulated your program's output with cat. You just replace the cat code with your program commands. Simple. :)
Double Quotes :
#!/bin/bash
expect -c "
spawn ssh user#domain
expect \"password\"
send \"mypassword\r\"
expect {\\\$} { puts matched_literal_dollar_sign}
send \"cat input_file\r\"; # Replace this code with your java program commands
expect -re {-\r\n(.*?)\s\s}
set output \$expect_out(1,string)
#puts \$expect_out(1,string)
puts \"Result : \$output\"
"
Single Quotes :
#!/bin/bash
expect -c '
spawn ssh user#domain
expect "password"
send "mypasswordhere\r"
expect "\\\$" { puts matched_literal_dollar_sign}
send "cat input_file\r"; # Replace this code with your java program commands
expect -re {-\r\n(.*?)\s\s}
set output $expect_out(1,string)
#puts $expect_out(1,string)
puts "Result : $output"
'
As you can see, I have used {-\r\n(.*?)\s\s}. Here the braces prevent any variable substitutions. In your output, we have a 2nd line with full of hyphens. Then a newline. Then your 3rd line content. Let's decode the regex used.
-\r\n is to match one literal hyphen and a new line together. This will match the last hyphen in the 2nd line and the newline which in turn make it to 3rd line now. So, .*? will match the required output (i.e. abcd 12) till it encounters double space which is matched by \s\s.
You might be wondering why I need parenthesis which is used to get the sub-match patterns.
In general, expect will save the expect's whole match string in expect_out(0,string) and buffer all the matched/unmatched input to expect_out(buffer). Each sub match will be saved in subsequent numbering of string such as expect_out(1,string), expect_out(2,string) and so on.
As Donal pointed out, it is better to use single quote's approach since it looks less messy. :)
It is not required to escape the \r with the backslash in case of double quotes.
Update :
I have changed the regexp from -\r\n(\w+\s+\w+)\s\s to -\r\n(.*?)\s\s.
With this way - your requirement - such as match any number of letters and single spaces until you encounter first occurrence of double spaces in the output
Now, let's come to your question. You have mentioned that you have tried -\r\n(\w+)\s\s. But, there is a problem here with \w+. Remember \w+ will not match space character. Your output has some spaces in it till double spaces.
The use of regexp will matter based on your requirements on the input string which is going to get matched. You can customize the regular expressions based on your needs.
Update version 2 :
What is the significance of .*?. If you ask separately, I am going to repeat what you commented. In regular expressions, * is a greedy operator and ? is our life saver. Let us consider the string as
Stackoverflow is already overflowing with number of users.
Now, see the effect of the regular expression .*flow as below.
* matches any number of characters. More precisely, it matches the longest string possible while still allowing the pattern itself to match. So, due to this, .* in the pattern matched the characters Stackoverflow is already over and flow in pattern matched the text flow in the string.
Now, in order to prevent the .* to match only up to the first occurrence of the string flow, we are adding the ? to it. It will help the pattern to behave as non-greedy manner.
Now, again coming back to your question. If we have used .*\s\s, then it will match the whole line since it is trying to match as much as possible. This is common behavior of regular expressions.
Update version 3:
Have your code in the following way.
x=$(expect -c "
spawn ssh user#host
expect \"password\"
send \"password\r\"
expect {\\\$} { puts matched_literal_dollar_sign}
send \"cat input\r\"
expect -re {-\r\n(.*?)\s\s}
if {![info exists expect_out(1,string)]} {
puts \"Match did not happen :(\"
exit 1
}
set output \$expect_out(1,string)
#puts \$expect_out(1,string)
puts \"Result : \$output\"
")
y=$?
# $x now contains the output from the 'expect' command, and $y contains the
# exit status
echo $x
echo $y;
If the flow happened properly, then exit code will have value as 0. Else, it will have 1. With this way, you can check the return value in bash script.
Have a look at here to know about the info exists command.
Hello and thank you for any help you can provide
I have my Apache2 web server set up so that when I go to a specific link, it will run and display the output of a shell script stored on my server. I need to output the results of an SVN command (svn log). If I simply put the command 'svn log -q' (-q for quiet), I get the output of:
(of course not blurred), and with exactly 72 dashes in between each line. I need to be able to take these dashes, and turn them into an html line break, like so:
Basically I need the shell script to take the output of the 'svn log -q' command, search and replace every chunk of 72 dashes with an html line break, and then echo the output.
Is this at all possible?
I'm somewhat a noob at shell scripting, so please excuse any mess-ups.
Thank you so much for your help.
svn log -q | sed -e 's,-{72},<br/>,'
If you want to write it in the script this might help:
${string//substring/replacement}
Replace all matches of $substring with $replacement.
stringZ=abcABC123ABCabc
echo ${stringZ/abc/xyz} # xyzABC123ABCabc
# Replaces first match of 'abc' with 'xyz'.
echo ${stringZ//abc/xyz} # xyzABC123ABCxyz
# Replaces all matches of 'abc' with # 'xyz'.
I am half-way through writing an Expect script on a Linux server which is supposed to telnet to a router in order to collect some system information. So far my script can successfully make the connection, run a router command, disconnect and terminate.
The command displays a few lines which I need to parse, something I am not sure how to do in Expect. How can I save the output, grep a line, then a column from the line, and finally save the result in a file? If possible, I would like to use Expect entirely rather than a work-around (for example Expect embdded in Bash).
Thanks for your time.
jk04
Two tips for expect development:
autoexpect to lay out a framework for your automation
exp_internal 1 to show verbosely what expect is doing internally. This one is indispensable when you can't figure out why your regular expression isn't capturing what you expect.
basically, $expect_out(buffer) [1]. holds the output from last expect match to the current one. you can find your command output there.
and for the string manipulation, you can simply employ the tcl's built-in [2][3].
"How to access the result of a remote command in Expect" http://wiki.tcl.tk/2958
"regexp" http://wiki.tcl.tk/986
"string match" http://wiki.tcl.tk/4385
I've faced and solved a similar problem for interacting with bash. I believe the approach generalizes to any other interactive environment that provides no-op, fixed-string output.
Basically, I wrap the command with two fixed strings and then search for the pattern that includes these strings at the beginning and end, and save the content in between them. For example:
set var "";
expect $prompt { send "echo PSTART; $command; echo PEND;\r"; }
expect {
-re PSTART\r\n(.*)PEND\r\n$prompt { set var [ string trim $expect_out(1,string) ]; send "\r"; }
-re $prompt { set var "" ; send "\r"; }
timeout { send_user "TIMEOUT\n"; exit }
}
I suspect that this approach would work with a shell's comment characters as well, or a simple status command that returns a known output.
Then you can do whatever you need with the content of 'var'.