Question

I’m trying to do some conditional text processing on Unix and struggling with the syntax. I want to acheive

Find the first 2, 3 or 4 digits in the string
if 2 characters before the found digits are 'WR' (could also be lower case)
    Variable = the string we've found (e.g. WR1234)
    Type = "work request"
else
    if 2 characters before the found digits are 'RN' (could also be lower case)
      Variable = the string we've found (e.g. RN1234)
      Type = "release note"
    else
      Variable = "WR" + the string we've found (Prepend 'WR' to the digits)
      Type = "Work request"
    fi
fi

I’m doing this in a Bash shell on Red Hat Enterprise Linux Server release 5.5 (Tikanga)

Thanks in advance,
Karl

Answer 1

I’m not sure how you read in your strings but this example should help you get there. I loop over 4 example strings, WR1234 RN456 7890 PQ2342. You didn’t say what to do if the string doesn’t match your expected format (PQ2342 in my example), so my code just ignores it.

#!/bin/bash

for string in "WR1234 - Work Request Name.doc" "RN5678 - Release Note.doc"; do
  [[ $string =~ ^([^0-9]*)([0-9]*).*$ ]]
  case ${BASH_REMATCH[1]} in
    "WR")
          var="${BASH_REMATCH[1]}${BASH_REMATCH[2]}"
          type="work request"
          echo -e "$var\t-- $type"
          ;;
    "RN")
          var="${BASH_REMATCH[1]}${BASH_REMATCH[2]}"
          type="release note"
          echo -e "$var\t-- $type"
          ;;
    "")
          var="WR${BASH_REMATCH[2]}"
          type="work request"
          echo -e "$var\t-- $type"
          ;;
  esac
done

Output

$ ./rematch.sh
WR1234  -- work request
RN5678  -- release note