Yes/no Shell Script Prompt Issue

[rhss6-2011]

I'm trying to create a yes/no prompt within a shell script that I'm making for someone else and it's starting to get irritating right now... I've been up and down the forums, checked my 833 page PDF book on Bash/Shell scripting for reference and I can not get this to work at all...
Every time I build a script with various aspects to it I test it out piece by piece. I usually use Zenity for prompts and other scripts, but this is for someone who doesn't have it installed on their system. So far everything works until the yes/no prompt here.

Here's the NOT WORKING test prompt:

#!/bin/bash
read -p "Yes or no? If you don't know please type 'no': " prompt
if [ $prompt == [Yy][Ee][Ss] ] ; then
    #Execute desired command if user agrees.
    printf "Thank you, please wait one moment \n"
    sleep 2
    #Execute functions
    function1
    sleep 2
    function2
    sleep2
    printf "Everything worked just fine without any errors, have a nice day!"
else
    #Exit if user decided against the action
    printf "Thank you for your time, have a nice day \n"
fi

My terminal output is

test.sh: 3: [: yes: unexpected operator
No worked just fine

The crazy thing is, I tested the function which works, I tested it using my zenity prompt, but as soon as I use my prompt above, it stops working!
Can anyone offer me some help or suggestions?

[rai4shu2]

Why not just check for "y" or "n"? Then it's a simple case of:

if "$prompt" = "y"; then

[steeldriver]

I think you might need to use the double bracket [[ ... ]] syntax (aka extended test) to get the regex test to work

if [[ $prompt == [Yy][Ee][Ss] ]] ; then

[rhss6-2011]

Thanks Steel diver but that didn't work either
I tried that before, and just now but:

Yes or no? If you don't know please type 'no': yes
test.sh: 3: test.sh: [[: not found
Thank you for your time, have a nice day

@rai4shu2

I want to make sure that anyone who types "yes" with caps or no, or whatever that it will work...

[steeldriver]

well it works for me... I copied your exact script and modified it (no spaces between the [[ btw i.e. '[[' and ']]' are keywords not literal brackets)

#!/bin/bash

read -p "Yes or no? If you don't know please type 'no': " prompt
if [[ $prompt == [Yy][Ee][Ss] ]] ; then
    #Execute desired command if user agrees.
    printf "Thank you, please wait one moment \n"
    sleep 2
    #Execute functions
    function1
    sleep 2
    function2
    sleep2
    printf "Everything worked just fine without any errors, have a nice day!"
else
    #Exit if user decided against the action
    printf "Thank you for your time, have a nice day \n"
fi

[sisco311]

[[ is a bashism. It doesn't work in dash (sh is a symlink to dash in Ubuntu).

I'd use a case statement

read -r ans
case $ans in
    [yY]|[yY][eE][sS])
        do something
        ;;
    [nN]|[nN][oO])
        do something else
        ;;
    *)
        whatever
        ;;
esac

[rhss6-2011]

I don't get it... I copied EXACTLY what you have, then:

usr@usr:path/to/script$ sh test.sh
Yes or no? If you don't know please type 'no': yes
test.sh: 4: test.sh: [[: not found
Thank you for your time, have a nice day 
usr@usr:path/to/script$

[sisco311]

sh is NOT bash.

[rhss6-2011]

Oh wow... I typed "bash test.sh" and it worked... Why does it do that if both commands run it!?!?