[SOLVED] Allow only one number in grep Regex

Issue

I have to accept the strings that only have a single number, it doesn't matter the content of the string, it just needs to be a single number.

I was trying something like this:

echo "exaaaamplee1" | grep '[0-9]\{1\}'

This string is accepted, but this string also is accepted:

echo "exaaaamplee11" | grep '[0-9]\{1\}'

Solution

You probably want to use something like [^0-9]. This represents any character except a digit 0-9, and you can use [0-9] (or \d) for the one digit that is allowed.

Something like ^[^0-9]*[0-9][^0-9]*$ should match any string with exactly one digit. (^ being the start and $ the end of the string)

Answered By - Timothy Egenton