Why does it require two key strokes to exit this script?

[GrouchyGaijin]

Hi Guys,

First, thanks to you in the Programming Talk sub-forum, I've learned a lot, but obviously not enough.

I have a couple of questions about bash scripting.

Here is the script:




#!/bin/bash
cd ~/gpodder
bin/gpo update && bin/gpo download
until [ "$x" = "Q" ]; do
echo "Press D to delete episodes, press S to sync or Q to quit. "
read x
if [ "$x" = "D" ]
then
rm /home/john/gpodder-downloads/"Coast to Coast AM Podcast"/*.mp3
elif [ "$x" = "S" ]
then
~/gpodder/bin/gpo sync
echo "Scroll up to see how things worked out."
fi
read x
if [ "$x" = "Q" ]
then
killall OldCoastScript
else
echo "Hey quit already "
fi
done


Question #1:
Why is it that if I choose Q without having run S or D then I need to press the Q key two times to terminate the script?

Question #2:
How should I write the script if I want more than three options? Example: S to sync, D to delete files on the computer, C to clean old files from the walkman and Q to quit.

Thanks guys, I really appreciate the help.

[alarme]

Hi

You are using two read statements.

Try some like this:



#!/bin/bash

cd ~/gpodder
bin/gpo update && bin/gpo download

until false; do
echo "Press D to delete episodes, press S to sync or Q to quit. "
read x

if [ "$x" = "D" ]; then
rm /home/john/gpodder-downloads/"Coast to Coast AM Podcast"/*.mp3
elif [ "$x" = "S" ]; then
~/gpodder/bin/gpo sync
echo "Scroll up to see how things worked out."
elif [ "$x" = "Q" ]; then
echo "Q"
killall OldCoastScript # ????
break # exit loop
else
echo "Hey quit already "
break
fi
done

[alarme]

One tip:

If you are unsure what are you doing, avoid sentences "dangerous" on tests.
If possible, comment lines containing sentences like "rm" and substitute with inoffensive ones as "echo here delete things"

Cheers

[GrouchyGaijin]

Thanks for the insight.
I removed the read command in:




read x
if [ "$x" = "Q" ]



and now the script terminates correctly.

[steeldriver]

A case... esac construction is often a neater way to do this kind of thing



#!/bin/bash

echo -e "Choose one of the following options:\nA - do something\nB - do domething else\nQ - quit"

while true; do
read -p "Please enter your choice: " input;
case "$input" in

a|A) echo "Doing something"
;;

b|B) echo "Doing something else"
;;

q|Q) echo "Quitting"
break;
;;

*) echo "Oops"
;;

esac
done

[GrouchyGaijin]

A case... esac construction is often a neater way to do this kind of thing



#!/bin/bash

echo -e "Choose one of the following options:\nA - do something\nB - do domething else\nQ - quit"

while true; do
read -p "Please enter your choice: " input;
case "$input" in

a|A) echo "Doing something"
;;

b|B) echo "Doing something else"
;;

q|Q) echo "Quitting"
break;
;;

*) echo "Oops"
;;

esac
done


Hey thanks SteelDriver - I'll give your suggestion a try.

[GrouchyGaijin]

@alarme

Thank you so much.
This seems to be working exactly the way I wanted it to work.



#!/bin/bash


cd ~/gpodder
bin/gpo update && bin/gpo download


until false; do
echo "Press D to delete episodes, press S to sync, C to clean or Q to quit. "
read x


if [ "$x" = "D" ]; then
rm /home/john/gpodder-downloads/"Coast to Coast AM Podcast"/*.mp3
elif [ "$x" = "S" ]; then
~/gpodder/bin/gpo sync
echo "Scroll up to see how things worked out."
elif [ "$x" = "C" ]; then
rm /media/WALKMAN/MUSIC/"Coast to Coast AM Podcast"/*.mp3
echo "The Walkman has been cleaned."
elif [ "$x" = "Q" ]; then
echo "Going down"
killall CoastTest2 # ???? This is just the name of the script.
break # exit loop
else
echo "Hey quit already "
break
fi
done





I appreciate the help.
I don't know why but the first time I tried to add the clean option I got an error that [C wasn't a command. I thought I had copied the syntax correctly, but I guess not. The odd thing was that I had the same error on quit, which came from your script. So I copied and pasted the way you wrote the sync part of the script, because that worked, and changed the letters and commands. The problem stopped after that.
One other thing is that until I added done at the end, I had an end of file error. I'm not sure when exactly you need to add done and when you do not.

In any case, thank you :p

[Vaphell]

done tells bash where the loop body (which starts with do) ends, just like fi ends if then/elsif then/else block and esac ends case statement


while <condition>/until <condition>/for x in .../for(( ... ))/select x in ...
do
stuff to repeat
done