Matching a string with a known prefix and suffix with regex using Grep

Question

I'm trying to match all strings with a known prefix and a mostly known suffix.

The prefix will be any 3 uppercase characters.

The suffix will be one uppercase C and zero or one numbers afterward. ex. C or Cx where x is any number

The middle substring is of unknown length and is uppercase letters only.

Examples:

GORABJKAC3 [match]
GORCCCCC [match]
GORBBBBCCC [match
GORBBBBCA [no match]
BORBBBBCA2 [no match]

I tried something like grep ^GOR[:upper:]*C[:digit:]* but that doesn't work.

I think [:upper:] may just consume all uppercase letters, including the suffix C I want to match.

How can I match my desired string with regex using grep?

Answer 1

You can use this regex:

\b[A-Z]{3}.*?C[0-9]?\b

RegEx Demo

Or using anchor (if these strings are on separate lines):

^[A-Z]{3}.*?C[0-9]?$

Answer 2

Use [AZ] instead of [:upper:] and [0-9] instead of [:digit:] .

Also, * means 0 or more, + means 1 or more, and ? means 0 or 1. I think you want to be using + and ? .

+ and ? are special Perl regex characters so add the -P flag to your grep command.

So final regex : grep -P ^GOR[AZ]+C[0-9]?