Bash 脚本正则表达式问题

Question

I've got the following code and have looked at numerous examples but cannot figure out what I'm doing wrong. I know the regular expression works (see https://regex101.com/r/cB9hN1/1 ) - just not in my bash script. It's for a git update hook, but clearly I'm doing something wrong! Here's what I've got:

regex='ref:( |)([D]|[U])([E]|[S])(\d+)';
string="My commit ref: US2233556"

if [[ $string =~ $regex ]];
  then
    echo "[SUCCESS] Your message contains ref: for a Story or Defect."
    exit 0
else
    echo "[POLICY] Your message is not formatted correctly. Please include a \"ref: USXXXXX\" or \"ref: DEXXX\" in the commit message."
    exit 1
fi

I'd appreciate any help! Thank you!

Answer 1

You should use [0-9] instead of \\d and you can merge alternated character classes into single classes ( [D]|[U] = [DU] ):

regex='ref:( |)([DU])([ES])([0-9]+)';

See demo here

If you are not using capture groups, just remove them:

regex='ref: ?[DU][ES][0-9]+';

Here is another demo . Note that ( |) can be written shorter as ( ?) or ( )? and this way it will cause less backtracking.