I'm working on a shell script, which has lot of network calls and installations. When it is executed I need to enter yes/no for each prompt. Which is fine.
But now i have a requirement to run it as cron. In which case i won't be able to give inputs for each of the prompt that comes up.
Is there any way I can automate this or have some mechanism of knowing in script that a prompt has come up?
Use the yes command to answer interactive prompts,
yes Y | ./script.sh
The above syntax constantly puts the string Y to all your prompts. You can pass the string as you need after yes.
You can also use expect tool meant for this, but you need to know the exact prompt message for capturing and responding to it accordingly. If your prompt is simple and just need a simple input to pass yes would be the right tool.
Also you can use bash built-in printf, but you need to add the responses manually depending upon the number of prompts you have to respond to, e.g.
printf 'Y\nY\nY\n' | ./script.sh
to send response as Y for three prompts. As again, to avoid doing this manually, prefer using the yes command.
Related
I have a Bourne-Again shell script text executable named engine.bin that I want to install.
If I install the executable manually ./engine.bin I get a screen with the EULA I have to accept (by pushing space), then accept it by writing yes and then enter the installation path by typing /usr/local/engine.
Now I want to do the installation automatically through provisioning scripts without manual interaction. Is there a way to do this? I do not know if the installer accepts any parameters, unfortunately the thing is undocumented.
Based on the suggestion of bill-agee and jgr208 I wrote the following which is working for me:
#!/usr/bin/expect -f
set timeout -1
spawn /tmp/engine.bin
expect {
-gl "*Press SPACE or PAGE DOWN key to continue, U or PAGE UP key to scroll back*" { send -- " "; exp_continue }
-gl "*yes/no*"
}
send -- "yes\r"
expect -gl "*press ENTER to accept the default*"
send -- "/tmp/tce\r"
expect eof
If the executable allows you to spam input at it without waiting for each separate prompt to appear, you might be able to accomplish this with bash.
For example, this script will run program_that_takes_several_lines_of_input.py and send it four lines of input - three with text and one blank line:
#!/bin/bash -eux
./program_that_takes_several_lines_of_input.py <<EOD
first line
one enter keypress later
yet another line of input after the empty line above
EOD
If you need to stop and wait for each prompt to appear, the cram Python package may be a good fit for this scenario - I find it useful for tasks like this where you only need to send a few lines of input, but each line of input is different.
See:
https://bitheap.org/cram/
https://pypi.python.org/pypi/cram
Expect would also work, but I find that I reach working solutions a bit faster when using cram than with Expect.
pexpect is a great choice as well! See:
https://pexpect.readthedocs.org/en/stable/
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 run a linux command that sometimes asks for user input (press y or n).
After that for the same command I need to pass (yes/no)
I always want to answer y,and after that yes, how can I pass this value automatically ?
For 1 argument I knew that we can use
echo y|command
But,for multiple inputs I do not know how????
After Passing y, I should also able to give yes
Is there a way???
Use yes Utility
You can use the yes command if you always want to pass the same value. For example:
yes | ./script.sh
Use Expect, Variables, or Configuration Files
If you need anything more complex, then yes usually can't do what you want directly. Instead, you should use expect to script complex interactions, or rewrite your shell scripts to use variables or configuration files to pass parameters.
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.
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.