'How to reverse Regex comparison in BASH
how can I reverse my regex comparison result
Solution 1:[1]
The problem is that the regular expression is invalid. Specifically, the bracket expression ([a-z0-9-_]) is invalid because it contains a dash in the wrong place.
To include a literal dash character in a bracket expression, you need to put it at the beginning of the expression ([-otherchars]), at the end ([otherchars-]), or at at the end of a range ([*--] will match "*", "+", ",", and "-" in the C locale). Your bracket expression includes 0-9-_, which looks like two ranges stuck together, and is invalid.
To fix it, just move the "-" to the beginning or end of the bracket expression:
USERNAME_REGEX="^[a-z0-9_-]{2,15}$" # or
USERNAME_REGEX="^[-a-z0-9_]{2,15}$"
Sources
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Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Gordon Davisson |