Bash script need help with Loop

[Purell86]

hey i need some help with a loop statement. i know i'm close at least i think i am.

i have a file called colors.txt that has this in it:



white
black
red
blue
yellow


now im making a small script that asks the user "choose a color" and if the user spells the word incorrectly or chooses a color thats not in the list i need to loop it by asking the user" try again"

i thought i could try it using the while loop but im having problems with it:



#!/bin/bash

read -p "choose a color: " Color

grep_color="$(grep -i -w $Color colors.txt)"

while [ -z "$grep_color" ]
do
read -p " try again: " Color

done



still not working the way i want to
hopefully someone can fix my script
thanks in advanced

[ibuclaw]

hey i need some help with a loop statement. i know i'm close at least i think i am.

i have a file called colors.txt that has this in it:



white
black
red
blue
yellow


now im making a small script that asks the user "choose a color" and if the user spells the word incorrectly or chooses a color thats not in the list i need to loop it by asking the user" try again"

i thought i could try it using the while loop but im having problems with it:



#!/bin/bash

read -p "choose a color: " Color

grep_color="$(grep -i -w $Color colors.txt)"

while [ -z "$grep_color" ]
do
read -p " try again: " Color

done



still not working the way i want to
hopefully someone can fix my script
thanks in advanced

Try to think in a procedural manner.
You have the while loop running forever because the variable ($grep_color) never changes once you enter the loop.

Putting the grep command inside the while loop will fix your issue.


while ! grep -iwq "$Color" dab.c
do
read -p " try again: " Color
done

# Assign the value after validating it.
grep_color=$(grep -iw "$Color" dab.c)

[Martin Witte]

see this link (http://tldp.org/LDP/abs/html/commandsub.html) on how to store the result from a command into a variable

[Purell86]

GOT IT THANKS A LOT Tinivole (http://ubuntuforums.org/member.php?u=490875)

[ibuclaw]

GOT IT THANKS A LOT Tinivole (http://ubuntuforums.org/member.php?u=490875)

Your welcome, but the real question is...

Do you understand it?

[Purell86]

oh definately it makes perfect sense i think i was practically working backwards in my script.. that why i was getting errors

[ghostdog74]

here's a simple construction with bash, without using external tools like grep etc



declare -a ARRAY
exec 10<"file"
let count=0
while read LINE <&10; do
ARRAY[$count]=$LINE
((count++))
done
exec 10>&-

while true
do
read -p "choose a color, [Q|q] to quit: " Color
ELEMENTS=${#ARRAY[@]}
for (( i=0;i<$ELEMENTS;i++)); do
case "${ARRAY[${i}]}" in
$Color) echo "found: $Color";break;;
* )echo "Not found: ";break;;
esac
done
done