Have bash script answer interactive prompts

Question

Is it possible to have a bash script automatically handle prompts that would normally be presented to the user with default actions   Currently I am using a bash script to call an in-house tool that will display prompts to the user  prompting for Y N  to complete actions  however the script I m writing needs to be completely  hands-off   so I need a way to send Y N to the prompt to allow the program to continue execution   Is this possible

User · Answer

There is a special build-in util for this - 'yes'.

To answer all questions with the same answer, you can run

yes [answer] |./your_script

Or you can put it inside your script have specific answer to each question

User · Answer

In my situation I needed to answer some questions without Y or N but with text or blank   I found the best way to do this in my situation was to create a shellscript file   In my case I called it autocomplete sh  I was needing to answer some questions for a doctrine schema exporter so my file looked like this   -- This is an example only --  php vendor bin mysql-workbench-schema-export mysqlworkbenchfile mwb   doctrine  lt  lt  EOF   Export to Doctrine Annotation Format                                      1   Would you like to change the setup configuration before exporting         y   Log to console                                                            y   Log file                                                                  testing log   Filename   entity   extension      Indentation  4     Use tabs  no     Eol delimeter  win  unix   win     Backup existing file  yes     Add generator info as comment  yes     Skip plural name checking  no     Use logged storage  no     Sort tables and views  yes     Export only table categorized       Enhance many to many detection  yes     Skip many to many tables  yes     Bundle namespace       Entity namespace       Repository namespace       Use automatic repository  yes     Skip column with relation  no     Related var name format   name  related      Nullable attribute  auto  always   auto     Generated value strategy  auto  identity  sequence  table  none   auto     Default cascade  persist  remove  detach  merge  all  refresh     no     Use annotation prefix  ORM      Skip getter and setter  no     Generate entity serialization  yes     Generate extendable entity  no                                            y   Quote identifier strategy  auto  always  none   auto     Extends class       Property typehint  no   EOF   The thing I like about this strategy is you can comment what your answers are and using EOF a blank line is just that  the default answer    Turns out by the way this exporter tool has its own JSON counterpart for answering these questions  but I figured that out after I did this      to run the script simply be in the directory you want and run  sh autocomplete sh  in terminal   In short by using  lt  lt  EOL  amp  EOF in combination with Return Lines you can answer each question of the prompt as necessary   Each new line is a new answer   My example just shows how this can be done with comments also using the   character so you remember what each step is   Note the other advantage of this method is you can answer with more then just Y or N     in fact you can answer with blanks   Hope this helps someone out

User · Answer

This is not  auto-completion   this is automation  One common tool for these things is called Expect   You might also get away with just piping input from yes

User · Answer

If you only have Y to send       gt  yes Y    your script   If you only have N to send       gt  yes N    your script

User · Answer

I found the best way to send input is to use cat and a text file to pass along whatever input you need   cat  input txt      Script sh

User · Answer

A simple  echo  Y Y N N Y N Y Y N      your script   This allow you to pass any sequence of  Y  or  N  to your script

[linux] Have bash script answer interactive prompts

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