Linux Bash Script - Yes or No - read answer

Question

little script

#!/bin/sh

cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 24 | head -n 4

printf 'do you like this? (y/n)? '
read answer
if [ "$answer" != "${answer#[Yy]}" ] ;then
    echo Yes
else
    echo No
    goto?!? jumpto?!? urandom line
fi

it reads from urandom and ask if this ok, if yes the script end.

if not yes, i will read and ask again - how to do this?

do i need goto? or jumpto or anything other?

Answer 1

As I understand it, you want to execute an infinite loop containing your script, and exit from the script when the answer to the prompt is y.

The way to create an infinite loop in bash is using while true:

while true ; do
    # script
done

The way to exit from a script is using the appropriately named exit.

That would make your script:

#!/bin/sh

while true ; do
    cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 24 | head -n 4
    printf 'do you like this? (y/n)? '
    read answer
    if [ "$answer" != "${answer#[Yy]}" ] ;then
        echo Yes
        exit 0
    else
        echo No
    fi
done

There are a number of other remarks for your consideration.

The #!/bin/sh ensures that the script runs under sh and not under bash. If you want to use bash, change the line to #!/bin/bash.

read is able to provide the prompt for you. You do not need a printf for that.

read -p 'do you like this? (y/n)? ' answer

As if condition, I would (in bash, sh does not support this):

if [[ $answer =~ ^[yY] ]]; then

That is more readable (I think).