I'm using expect scripts to reconfigure a bunch of Cisco routers. Mostly, its working well, I have a file of addresses that is read by a script, which passes the addresses, one at a time to another script that logs on, goes into enable mode, then pulls a series of router configuration commands from a test file, which it issues to the router.
That worked well until I tried to script the logon banner. In this process, you issue the router a command line with a delimiter character, then follow that with whatever you want to have as a banner, formatted as you want to see it, then finish the banner off with a second delimiter character.
That gives a problem: when you move from one line to the next (with C/R) when building the banner, each new line starts with just a blank line (unlike a successful command, which will open a new line with #). That means that expect has no trigger to let it know to place the next line of banner, so it hangs.
I've tried things with embedded "\n" and "0x0a" to no avail.
has anyone any suggestions? has anyone succeeded in doing this before?
OK, I fixed it. Expect is waiting for the # prompt before it provides the next line. If you end each line of the banner with a #, it works, even though the C/R and # are round the wrong way. It may not be the most tidy programming but it works
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I've compiled my first web crawler script with AppleScript and I'm at the point now where I've gained a lot of knowledge and tricks from what I've written. I want to parse down the script now and disable some things that I thought would be helpful (for example: I coded it so the script completely quits Excel after entering the data in some workbooks from web pages because I noticed when you didn't start Excel fresh running the code it would return an error. But now I have the script running every 15 minutes so I worry that I will be working in Excel on some forecasting or formatting and the script will run and kick me out of Excel while I'm working and interrupt me or worse, quit without the option of saving). I vaguely remember C++ coding there was the ability to mark some text with a certain character that disabled it from running in the environment but made it so you could still see the original code before editing out stuff you decided wasn't necessary. Is there a way to mark a certain statement with a symbol so that AppleScript doesn't run the commands? I haven't experimented at all but I don't know what to guess that would do it. I may be mistaken that you can blank out or "white out" text while leaving it in the original position, still readable and able to be put back in when you want it or left for you so you have a collection of all the research you put into the process of building a script for a project. Well I suppose I'll just wonder a while and find something else to burn hours on.
In applescript there are three ways to "comment" out text in your code.
--A line beginning with two dashes is a comment.
#In applescript 2.+, the number sign also works as a comment symbol.
(* Multi-line text
can be commented out
using these symbols. *)
(Please, help me adjust title and tags.)
When I run connmanctl I get a different prompt,
enrico:~$ connmanctl
connmanctl>
and different commands are available, like services, technologies, connect, ...
I'd like to know how this thing works.
I know that, in general, changing the prompt can be just a matter of changing the variable PS1. However this thing alone (read "the command connmanctl changes PS1 and returns) wouldn't have any effect at all on the functionalities of the commands line (I would still be in the same bash process).
Indeed, the fact that the available commands are changed, looks to me like the proof that connmanctl is running all the time the prompt is connmanctl>, and that, upon running connmanctl, a while loop is entered with a read statement in it, followed by a bunch of commands which process the the input.
In this latter scenario that I imagine, there's not even need to change PS1, as the connmanctl> line could simply be obtained by echo -n "connmanctl> ".
The reason behind this curiosity is that I'm trying to write a wrapper to connmanctl. I've already written it, and it works as intended, except that I don't know how to properly setup the autocompletion feature, and I think that in order to do so I first need to understand what is the right way to write an interactive shell script.
I am creating a browser-based application for interacting with my local terminal, and I'm using the script command in the terminal (actually in a Java process) to feed input and capture output to display in the browser.
I have found that the virtual terminal inside the script process has 80 columns by default, and when a line of input exceeds that number, I see unexpected behavior. When it reaches the length limit, it adds a space, then a return, then continues with the line. For example, if I input the following:
user_name ~/my/current/directory$ ls /some/really/long/path/to/some/directory/somewhere
The following is what is actually transcribed (and forwarded to my browser app):
user_name ~/my/current/directory$ ls /some/really/long/path/to/some/directory/so ^Mmewhere
Notice the so ^Mmewhere instead of somewhere.
When I hit the up arrow after that to retrieve the last input, I get something different:
user_name ~/my/current/directory$ ls /some/really/long/path/to/some/directory/som^Mmewhere
This time, instead of the extra space character, it's duplicating the m: som^Mmewhere.
What is going on here? Is it that the script command is really intended to produce text output for a human reader, and therefore favors visual formatting over executability? Is there an alternative to script that would work better for my purpose?
Edit
I should have mentioned that I'm doing this in macOS Sierra. Not sure if that makes a difference.
How can I capture the input/ output from a script in realtime (such as with tee), but line-by-line instead of character-by-character? My goal is to capture the input typed into the interactive prompts of a script only after backspaces and auto-completion have finished processing (after the RETURN key is hit).
Specifically, I am trying to create a wrapper script for ssh that creates a timestamped log of commands used on remote servers. The script, which uses tee to redirect the output for filtering, works well, but the redirected output gets jumbled with unsubmitted characters whenever I use the backspace key or the up/down keys to scroll through my remote history. For example: service test stopexitservice test stopart or cd ..logs[1Pls -al.
Perhaps there is a way to capture the terminal's scrollback and redirect that like with tee?
Update: I have found a character-based cleanup solution that does what I want most of the time. However, I am still hoping for an answer to this question (which may well be msw's answer that it is very difficult to do).
In the Unix world there are two primary modes of handling keyboard input. These are known as 'raw' in which characters are passed from the terminal to the reading program one at a time. This is the mode that editors (and such) will use because the editor needs to respond immediately when you press a key.
The other terminal discipline is called 'cooked' which is the line by line behavior that you think of as the bash line by line input where you get to backspace and the command is not executed until you press return. Ssh has to take your input in raw, character-by-character mode because it has no idea what is running on the other side. For example, if you are running an editor on the far side, it can't wait for a return before sending the key-press. So, as some have suggested, grabbing shell history on the far side is the only reasonable way to get a command-by-command record of the bash commands you typed.
I oversimplified for clarity; actually most installations of bash take input in raw mode because they allow editor like command modification. For example, Ctrl-P scrolls up the command history or Ctrl-A goes to the beginning of the line. And bash needs to be able to get those keys the moment they are typed not waiting for a return.
This is another reason that capturing on the local side is obnoxiously difficult: if you capture on the local side, the stream will be filled with Backspaces and all of bash's editing commands. To get a true transcript of what the remote shell actually executed you have to parse the character stream as if you were the remote shell. There also a problem if you run something like
vi /some_file/which_is_on_the_remote/machine
the input stream to the local ssh will be filled with movement commands snippets of text including backspaces and so on and it would be bloody difficult to figure out what is part of a bash command and what is you talking to the editor.
Few things involving computers are impossible; getting clean input from the local side of an ssh invocation is really, really hard.
I question the actual utility of recording the commands that you execute on a local or remote machine. The reason is that there is so much state which is not visible from a command log. As a simple example here's a log of two commands:
17:00$ cp important_file important_file.bak
17:15$ rm important_file
and two days later you are trying to figure out whether important_file.bak should have the contents you intended or not. Given that log you can't answer that simple question. Even if you had the sequence
16:58$ cat important_file
17:00$ cp important_file important_file.bak
17:15$ rm important_file
If you aren't capturing the output, the cat in the log will not tell you anything. Give me almost any command sequence and I can envision a scenario in which it will not give you the information you need to make sense of what was done.
For a very similar purpose I use GNU screen which offer the option to record everything you do in a shell session (INPUT/OUTPUT). The log it creates also comes with undesirable characters but I clean them with perl:
perl -ne 's/\x1b[[()=][;?0-9]*[0-9A-Za-z]?//g;s/\r//g;s/\007//g;print' < screenlog.0
I hope this helps.
Some features of screen:
http://speaking-my-language.blogspot.com/2010/09/top-5-underused-gnu-screen-features.html
Site I found the perl-oneliner:
https://superuser.com/questions/99128/removing-the-escape-characters-from-gnu-screens-screenlog-n
I'm writing a command interpreter like BASH, and a \ followed by a newline implies a continuation of the input stream; how can I implement that in Win32?
If I use the console mode with ENABLE_LINE_INPUT, then the user can't press backspace in order to go back to the previous line; Windows prevents him from doing so. But if I don't set ENABLE_LINE_INPUT, then I have to manually reposition the cursor, which is rather tedious given that (1) the user might have redirected the input stream, and that (2) it might be prone to race conditions, and I'd rather have Windows do it if I can.
Any way to have my newline and eat it too?
Edit:
If this would require undocumented CSRSS port requests, then I'm still interested!
Assuming you want this to run in a window, like command prompt does by default, rather than full screen, you could create a GUI application with a large textbox. Users would type into the textbox, and you could parse whatever was entered, and output to the same box (effectively emulated the Win32 Console).
This way whatever rules you want to set for how the console behaves is completely up to you.
I might be mistaken is saying this, but I believe that the Win32 Console from XP onward works exactly like this, and it just listens for output on stdout; there shouldn't be any reason you can't do the same.
Hope this was helpful.