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Edit:

Seems to work within bash. It appears the problem is related to zsh. If there is a better site to post this issue on let me know.


I am writing a simple script that creates a series of directories. I want the user to give a confirmation before I do so. I'm using the following as a basis, but cannot seem to get it to run within a bash function. If I put it outside of a function it works fine. Here is an isolated example:

read.sh

#!/bin/bash
test() {
  read -p "Here be dragons. Continue?" -n 1 -r
  if [[ $REPLY =~ ^[Yy]$ ]]
  then
    echo "You asked for it..."
  fi
}

code from this SO post.

Sourcing the file and/or test results in the following error: read:1: -p: no coprocess. Same output when I place it in my .bashrc

Edit::

@hennes

  1. I want the function to be in a config file, so I can call it from whatever directory (ideally my .bashrc or .zshrc)
  2. I've corrected the formatting of the first commented line. Problem still exists in zsh
  3. Bash version is 3.2, but you've helped me figure out that the problem is with zsh and not bash.
share|improve this question
    
1) Is there any place where you actually call the function test() ? 2) #! /bin/bash with a space behind she shebang? I thought those were not allowed? 3) '#!/usr/bin/env bash' is probably better. 4) Which bash version? (I tested with bash 4.1.10 on FreeBSD and got no errors) –  Hennes Feb 22 '13 at 17:05
    
I improperly tagged the question, I'm using zsh but didn't think that there would be conflict with bash scripts (i have several other similar scripts running all right). I've retagged it, and responded to your questions. Thanks for pointing me in the right direction! –  Nick Tomlin Feb 22 '13 at 17:33
    
How do you start the program? The shebang (#!)interpreter` line is only needed if you want to execute the file with ./read.sh. It is not needed it you run it in any other way or if you put it in an startup script. And if you want to run it in zsh with `zsh ./read.sh' then the lines starting with a # get ignored. They also confuse since their give the impression that you use bash when you use zsh). –  Hennes Feb 22 '13 at 20:48

2 Answers 2

up vote 6 down vote accepted

The –p option doesn’t mean the same thing to bash’s read built-in command and zsh’s read built-in command.  In zsh’s read command, –p means –– guess –– “Input is read from the coprocess.”  I suggest that you display your prompt with echo or printf.

You may also need to replace –n 1 with –k or –k 1.


The zsh equivalent of bash's read -p prompt is

read "?Here be dragons. Continue?"

Anything after a ? in the first argument is used as the prompt string.

And of course you can specify a variable name to read into (and this may be better style):

read "brave?Here be dragons. Continue?"
if [[ "$brave" =~ ^[Yy]$ ]]
then
    ...
fi

(Quoting shell variables is generally a good idea, too.)

share|improve this answer
    
Thanks for the explanation of why this is not functioning properly. I will check for differences like this in the future. –  Nick Tomlin Feb 22 '13 at 22:04

This code seems to do what you want in zsh.
(Note that the question you refered to explicitly mentions it is for bash).

#!/usr/bin/env zsh

test()
{
  echo -n "Here be dragons. Continue?"
  read REPLY

  if [[ $REPLY =~ ^[Yy]$ ]]
  then
    echo "You asked for it..."
  fi
}

test

Three comments:

share|improve this answer
    
Thank you for your help. I've given the answer to @scott because of the explanation of why this is not functioning, but the snippet you've given me works perfectly. –  Nick Tomlin Feb 22 '13 at 22:05
1  
Just three more things: This was probably best asked on SO (as it is a programming question). 2) Not all shells are compatible (man zsh returns different stuff for read -p then man bash does. 3) Another solution would be to searchj for vared -c -p 'prompt question' –  Hennes Feb 22 '13 at 22:10
    
+1 Thanks for letting me know. I'll direct future programming-centric questions to SO. –  Nick Tomlin Feb 22 '13 at 22:31

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