Output in grep command

Question

I'm new with regexp and I believe this is a beginner's glitch in getting the output.

My regexp for AB(CD) digits/digits is: [A-Z]+[^a-zA-Z0-9][A-Z]+[^a-zA-Z0-9] [0-9]+[^a-zA-Z0-9][0-9]+

Grep command is: grep "regexp" xyz.txt

there's no output to above command, but when I use sublime editor for same regex, i gets the desired result. Tried many attempts with grep command , the only time it gave results is when I deleted the [0-9]+[^a-zA-Z0-9][0-9]+ portion from regex because there is a space in between but still the results were not desired. Tried grep -e and grep --regexp= too, no results.

Can someone tell me where I went wrong or the correct syntax for this command. Much grateful.

Edit:

The data looks like the following:

AB(C.D.) nnnnn/nnnnnn A.B(C.D.) nnnnnn/nnnnn A.B.(CD) nnnnn/nnnnnn AB(CD) nnnnn/nnnnnn AAB(CD) nnnnn/nnnnnn .... .... further P & C

I was looking only for AB(CD) nnnn/nnnnnn. Would really like to learn the correct expression.

Answer 1

Use grep -E as it switches grep into a special mode so that the expression is evaluated as an ERE (Extended Regular Expression) as opposed to its normal pattern matching.