We have a shell script that expects multiple user inputs to be entered when prompted. e.g
At first it may ask for the operation to be performed. When that answer is given, it may ask for username then password etc. We want to automate this task by providing the inputs using file redirection i.e.
script < input.
The input file will have all the answers for different questions that the script may ask. However it is not working and the shell script is reading only the first line of the input file. What do I need to change or use to make this work?
What you can use is the program expect. You create a script for it that tells it when to give what input to some command it executes. This way you can automate exactly the kind of thing you're struggling with.
More info on Google and here:
http://www.linuxjournal.com/article/3065
man page: http://linux.die.net/man/1/expect
You say 'it only reads the first line of input.'
So you have to kill the script?
Is there any output? (error messages especially)?
Are you redirecting STDERR to /dev/null or else where? If so, remove that.
Here is the hightest probability helper ... Modify the top-level script and add set -vx at the 2nd line. Then you'll be able to see what was processed, where it has stopped and possibly formulate theories about why it is not processing data.
Any chance that the input file was created in a Windows environment and the cr\lf pair is messing up the expected input?
I hope this helps.
Thanks all for commenting and answering. I tried except and that did not work. So I am going to mention what worked for us. Here was our workflow - 1. At the linux prompt, type the command, it was connect() in our case. 2. Once that command is given, the script would ask for parameters for the command like port number, server etc. we had to provide that manually 3. Then we again are presented with a shell prompt with another input. In our case, we were able to provide the first command connect() at the prompt using file redirection, but the parameter passing was an issue. The solution we found was provide the parameters inside the parentheses of connect only i.e. our input file for redirection would contain - connect(). This worked for us.
Related
EDIT: I'm re-writing this because the first time was a bit unclear.
Let's say I have a program (an executable) such that when I run it, it prompts me to enter an input.
For example, I execute ./myProgram
and the program prompts: Please enter your username:
Here, I would type in my username.
Now, how would I write a bash script so that after I start the above program, I can enter inputs to it?
Something along the lines of this:
#!/bin/bash
path/to/myProgram
# And here I would enter the commands, such as providing my username
Thanks
reading values interactively is rather uncommon in *nix scripts, and is frowned upon by those who want to do exactly what you're trying to do. The standard way of doing this would be changing myProgram to accept arguments. At that point it's trivial to do this.
If you really need to use this pattern you need to use some tool like expect, as pointed out by #EricRenouf.
If myProgram reads from standard input, you can use a here-document:
path/to/myProgram <<\END
username
more input if needed
END
I need to run a shell script that should interact with couple of servers / routers in daily schedule. The script will simply login to the remote end, run a command. Up to here i hear that you are saying it is easy. The real problem here is that i need to analyze the output of the first command and based on the output i need to organize the second command. This is also doable, but the situation here is that i do not want to login and logout from the box for every command.
What i need is to login once, stay alive ,run the command take the output, analyze it and then run the second command later on logout and close connection.
Correct me if i am wrong but expect is not an option here. I want to ask for your suggestions.
Which language / module of this language i can use to complete this requirement.
Environment is not pure ssh, so i should have something general that can be used for both ssh/telnet.
Thanks in advance
Since you mentioned python, pexpect should do the job pretty well:
https://pexpect.readthedocs.org/en/latest/overview.html
Trying to make a small script and cron job it in order to automate a task. Said script runs another script which has already been created, grabs the output, emails to specified recipients, and cleans up the output. I've got it almost down however am running into one major issue. The script that mine is running has a menu on the outset. That is to say, running the script by itself manually, i would have to select option 1 in order to get the output i want (the only other option, 2, is quit.)
How can I automatically enter (or simulate entering) the value 1 into the other script, so it does not hang when in a cron job waiting for user input?
Is there a sane way to do this?
Thanks in Advance.
You could try something as simple as using yes | command if answering yes is all that is needed. Otherwise you probably want to use expect to drive the imaginary keyboard for you.
http://expect.sourceforge.net/
Using autoexpect to record your session is a convenient way to come up with rough draft expect scripts as well.
I wanted to know if there was some means of keeping track of every command executed on command line in a chronological manner along with the working directory where it was executed and the output of the command. Like putting all of this information for a session into a log file that you can go through later.
The acct program allows the system administrators to know exactly what their users were doing on their command line.
This site: http://www.cyberciti.biz/tips/howto-log-user-activity-using-process-accounting.html has a detailed description on how to enable it.
I'm looking for a method to check from within my shell script that script specific completion have been initialized by user using complete -F ...
I want this check to print out an advice on how to initialize the completion like:
Warning: Auto completion is not initialized. Please run : source ....; complete -F ...
The problem is that the script,being run in a sub-shell has no information about "complete" environment of the parent shell where user is working.
So complete -p| grep my-script-name never return any result.
User is expected to run "source" and "complete" commands or add them into his .bashrc manually, because we're working on a server where we have no access to the bash completion system directory.
Alternatively if you know a method of initializing(and not only checking) the auto-complete from within the script, I would happily accept it.
The only way your script can have access to such information for the parent shell is if it is included instead of executed as a sub-shell. Rather than instructing your users they can include some configuration, you can design your script so it works whether it is run or included.
Then you can simply inform your users that if they want completion enabled they need to include your script rather than run it as an executable script (with instuctions to use source or . as you wish).
However, in this case, I would be inclined to either add this information in documentation or add it into a banner which is always displayed (but can be disabled with an option switch like -q), rather than support two modes of running the script (since the gain is so small).
Either you want every user to use bash completion (which I don't think is good, for example I prefer to have it turned off), or let users decide themselves, but having them this message printed out on each TABTAB is a threat, don't you think?
I'd put into /etc/bash.bashrc what you think every user should run.