Issue
Say I have a simple statement:
read number
[[ ! $number =~ ^[1-3245][,][1-3245]$ ]] && echo "Not a valid number."
I want to check to see if the number is between 1-3245. But it seems like it's looking for a number between 1 and 3 for the first integer, then 2,4,5. How do get this to check if the number entered looks like 1-3245,1-3245? I've tried with {} and .. instead of - But still no go. I'd like to avoid a crazy long string .
*Edit I should be more specific here. I am looking to check user input and match it to a desired format; that format being 'int,int,int....' where int is = an integer between 1-3245. I hope this makes sense.
Solution
Assuming your criteria is: integer between 1 and 3245 (included), comma, integer between 1 and 3245 (included), you can use a mixture of regular expression and arithmetic:
$ foo() {
[[ "$1" =~ ^([0-9]*),([0-9]*)$ ]] || return 1
a=${BASH_REMATCH[1]}; b=${BASH_REMATCH[2]}
(( a >= 1 && a <= 3245 && b >= 1 && b <= 3245 ))
}
$ foo 2,2 && echo "OK" || echo "Not a valid number."
OK
$ foo 2,4000 && echo "OK" || echo "Not a valid number."
Not a valid number.
$ foo 2,bar
Not a valid number.
If the number of comma-separated integers is unknown (but minimum one) and you want to use only bashyou will need a loop:
$ foo() {
n="$1"
while [[ "$n" =~ ^([0-9]+)((,[0-9]+)*)$ ]]; do
(( BASH_REMATCH[1] < 1 || BASH_REMATCH[1] > 3245 )) && return 1
n="${BASH_REMATCH[2]#,}"
[[ -z "$n" ]] && return 0
done
return 1
}
$ foo 2,2,2,2,2 && echo "OK" || echo "Not a valid number."
OK
$ foo 2,2,4000,2,2 && echo "OK" || echo "Not a valid number."
Not a valid number.
$ foo 2,2,bar,2,2 && echo "OK" || echo "Not a valid number."
Not a valid number.
But if you can also use external utilities GNU awk would be a bit simpler:
$ foo() {
awk -F, 'NR > 1 { exit 1 } {
for(i=1; i<NF; i++)
if($i !~ /^[0-9]+$/ || $i < 1 || $i > 3245) exit 1
}' <<< "$1"
}
$ foo 2,2,2,2,2 && echo "OK" || echo "Not a valid number."
OK
$ foo 2,2,4000,2,2 && echo "OK" || echo "Not a valid number."
Not a valid number.
$ foo 2,2,2,bar,2 && echo "OK" || echo "Not a valid number."
Not a valid number.
Answered By - Renaud Pacalet Answer Checked By - Marilyn (WPSolving Volunteer)
