How do I prompt for input in a Linux shell script?

echo "Please enter some input: "
read input_variable
echo "You entered: $input_variable"

You can use the built-in read command. Use the -p option to prompt the user with a question.

Since BASH4, you can now use -i to suggest an answer, so the user only have to press return to enter it :

read -e -p "Enter the path to the file: " -i "/usr/local/etc/" FILEPATH

(But remember to use the "readline" option -e to allow line editing with arrow keys)

Bash has select for this purpose.

select result in Yes No Cancel
do
    echo $result
done

read -p "Are you alright? (y/n) " RESP
if [ "$RESP" = "y" ]; then
  echo "Glad to hear it"
else
  echo "You need more bash programming"
fi

Here's something I put together:

#!/bin/sh

promptyn () {
    while true; do
        read -p "$1 " yn
        case $yn in
            [Yy]* ) return 0;;
            [Nn]* ) return 1;;
            * ) echo "Please answer yes or no.";;
        esac
    done
}

if promptyn "is the sky blue?"; then
    echo "yes"
else
    echo "no"
fi

I'm a beginner, so take this with a grain of salt, but it seems to work.

echo "Do you wish to install this program?"  
select yn in "Yes" "No"; do  
case $yn in
    Yes ) make install; break;;
    No ) exit;;
esac
done

Hi Christopher, I used the above code in one of my bash script, even though it says select Yes or No it won't work if I press "Y" or "YES", rather I have to input "1" to say "YES" or 2 to say "NO", it does what it should on option "1" i.e. rm -rf filname (i am deleting a file after its downloaded and extracted) - once it has deleted it, it doesn't returns to the prompt rather it sits on ?#
Any ideas ? Your suggestions would be helpful Thanks again !

This solution reads a single character and calls a function on a yes response.

read -p "Are you sure? (y/n) " -n 1
echo
if [[ $REPLY =~ ^[Yy]$ ]]; then
    do_something      
fi

inquire ()  {
  echo  -n "$1 [$2/$3]? "
  read answer
  finish="-1"
  while [ "$finish" = '-1' ]
  do
    finish="1"
    if [ "$answer" = '' ];
    then
      answer=""
    else
      case $answer in
        y | Y | yes | YES ) answer="y";;
        n | N | no | NO ) answer="n";;
        *) finish="-1";
           echo -n 'Invalid response -- please reenter:';
           read answer;;
       esac
    fi
  done
}

... other stuff

inquire ""Install now? " "y" "n"

...

Where'd my formatting go? I guess that shows what happens if you cut and paste from unix text.

Sorry for posting on such an old post. Some weeks ago I was facing a similar problem, in my case I needed a solution which also worked within an online installer-script, eg: curl -Ss https://raw.github.com/_____/installer.sh | bash

Using read yesno < /dev/tty works fine for me:

echo -n "These files will be uploaded. Is this ok? (y/n) "
read yesno < /dev/tty

if [ "x$yesno" = "xy" ];then

   # Yes
else

   # No
fi

Hope this helps someone.

Use the read command:

echo Would you like to install? "(Y or N)"

read x

if [ "x" = "y"]

and then all of the other stuff you need

yn() {
  if [[ 'y' == `read -s -n 1 -p "[y/n]: " Y; echo $Y` ]];
  then eval $1;
  else eval $2;
  fi }
yn 'echo yes' 'echo no'
yn 'echo absent no function works too!'

Multiple choice version:

ask () {                        # $1=question $2=options
    # set REPLY
    # options: x=..|y=..
    while $(true); do
        printf '%s [%s] ' "$1" "$2"
        stty cbreak
        REPLY=$(dd if=/dev/tty bs=1 count=1 2> /dev/null)
        stty -cbreak
        test "$REPLY" != "$(printf '\n')" && printf '\n'
        (
            IFS='|'
            for o in $2; do
                if [ "$REPLY" = "${o%%=*}" ]; then
                    printf '\n'
                    break
                fi
            done
        ) | grep ^ > /dev/null && return
    done
}

Example:

$ ask 'continue?' 'y=yes|n=no|m=maybe'
continue? [y=yes|n=no|m=maybe] g
continue? [y=yes|n=no|m=maybe] k
continue? [y=yes|n=no|m=maybe] y
$

It will set REPLY to y (inside the script).

To get a nice ncurses-like inputbox use the command dialog like this:

#!/bin/bash
if (dialog --title "Message" --yesno "Want to do something risky?" 6 25)
# message box will have the size 25x6 characters
then 
    echo "Let's do something risky"
    # do something risky
else 
    echo "Let's stay boring"
fi

The dialog package is installed by default at least with SUSE Linux.

I suggest you use dialog...

Linux Apprentice: Improve Bash Shell Scripts Using Dialog

The dialog command enables the use of window boxes in shell scripts to make their use more interactive.

it's simple and easy to use, there's also a gnome version called gdialog that takes the exact same parameters, but shows it GUI style on X.