I want to pause input in a shell script, and prompt the user for choices. The standard 'Yes, No, or Cancel' type question. How do I accomplish this at a typical bash prompt?
Source: Tips4all, CCNA FINAL EXAM
Source: Tips4all, CCNA FINAL EXAM
I am looking to create a system which on signup will create a subdomain on my website for the users account area.
The simplest and most widely available method to get user input at a shell prompt is the 'read' command. The best way to illustrate its use is a simple demonstration:
ReplyDeletewhile true; do
read -p "Do you wish to install this program?" yn
case $yn in
[Yy]* ) make install; break;;
[Nn]* ) exit;;
* ) echo "Please answer yes or no.";;
esac
done
Another method, pointed out by Steven Huwig, is bash's 'select' command. Here is the same example using select:
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
With select you don't need to sanitize the input... it prompts you with your choices, and you type a number corresponding to the choice you want. Select also loops automatically... there's no need for a 'while true' loop to retry if they give invalid input.
echo "Please enter some input: "
ReplyDeleteread input_variable
echo "You entered: $input_variable"
Since BASH4, you can now suggest an answer (-i), so the user only have to press return to enter it :
ReplyDeleteread -e -p "Enter the path to the file: " -i "/usr/local/etc/" FILEPATH
(remember to use the readline option (-e) to allow line editing with arrow keys)
Bash has select for this purpose.
ReplyDeleteselect result in Yes No Cancel
do
echo $result
done
read -p "Are you alright? (y/n) " RESP
ReplyDeleteif [ "$RESP" = "y" ]; then
echo "Glad to hear it"
else
echo "You need more bash programming"
fi
Use the read command
ReplyDeleteJust do:
echo Would you like to install? "(Y or N)"
read x
if [ "x" = "y"]
and then all of the other stuff you need
I suggest you use dialog... 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.
ReplyDeleteinquire () {
ReplyDeleteecho -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.
echo "Do you wish to install this program?"
ReplyDeleteselect 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 !