Bash Script: "Yes/No" User Input.

[jusmurph]

I have begun playing with bash scripting and i want to make a very simple script for when i do a fresh reinstall.

Simply it is a list of:

"Sudo apt-get install XXX
Sudo apt-get install YYY...etc"

What i want to do is put in a question before each install so its something like:

"do you want to install XXX?
If yes sudo apt-get install XXX
if no continue onto the next line
do you want to install YYY?
If yes sudo apt-get install YYY
if no continue onto the next line...etc"

[Wybiral]

Look for info on the "read" command.

[vanadium]

i.e. type "info read" at the prompt. Curiously, there is no man page ("man read") available.

[Mr. C.]

This post has some examples of how to use the read command:

http://ubuntuforums.org/showthread.php?t=530833

MrC

[sacherjj]

How about something like this:

read -p "Install XXX (y/n)?"
[ "$REPLY" == "y" ] || sudo apt-get install XXX
read -p "Install YYY (y/n)?"
[ "$REPLY" == "y" ] || sudo apt-get install YYY

If the user types "y", it runs the or'ed (||) code. Otherwise it skips it.

Edit: Might want to force running as root when you start, instead of sudo'ing each statement, like my script that MrC linked to right above.

[Siljrath]

i just tried that out with my adapted script to test that out.

#!/bin/bash
echo hey!
read -p "write 'gooba gooba gooba' (y/n)?"
[ "$REPLY" == "y" ] || echo "gooba gooba gooba"
read -p "Install YYY (y/n)?"
[ "$REPLY" == "y" ] || sudo apt-get install YYY

and as this screenshot shows, i said yes to gooba and no to install, and it did it the wrong way around!
how'd that come about!?

edit:
ah!

Last edited by sacherjj; August 21st, 2007 at 07:46 PM.. Reason: changed != "y" to == "y".

you were right the first time.
glad u did that though, now i know how to make it a "press this" or a "press anything but this"

[Mr. C.]

Use && when you want the second part to run (be evaluated) when the first part is true.

Use || when you want the second part to run (be evaluated) when the first part is false.

[Siljrath]

Use && when you want the second part to run (be evaluated) when the first part is true.

Use || when you want the second part to run (be evaluated) when the first part is false.

ah, cool. so you can invert the true/false with both &&/|| and !=/==.


edit:
so for example,

#!/bin/bash
echo hey!
read -p "write 'gooba gooba gooba' (y/n)?"
[ "$REPLY" != "y" ] || echo "gooba gooba gooba"
read -p "Install YYY (y/n)?"
[ "$REPLY" == "y" ] && sudo apt-get install YYY

both work. ... except of course YYY is just a placeholder, not a package.

[geirha]

You can also combine them to get something similar to an if/else, though if either [[ or aptitude fails, it will jump to the part after ||

read -n1 -p "Install foo? (y/n) "
echo
[[ $REPLY = [yY] ]] && echo sudo aptitude install foo || { echo "You didn't answer yes, or installation failed."; exit 1; }

[lswb]

i.e. type "info read" at the prompt. Curiously, there is no man page ("man read") available.

"read" is part of bash, it is covered in "man bash"