Trouble getting regex to work with grep/sed - regex

Question

I've been working on a script to update the PRODUCT_BUNDLE_IDENTIFIER in a pbxproj file with a new value using a build script. The regex I've come up with selects everything between 'PRODUCT_BUNDLE_IDENTIFIER = ' and any text following up to 2 occurrences of '.' which is what I want.
The regex I've put together to find these occurences is shown here:
(?<=PRODUCT_BUNDLE_IDENTIFIER = )([a-zA-Z0-9_]+(?:\.[a-zA-Z0-9_]+){0,2})
I've tested it with a validator here: https://regex101.com/r/jUhJm7/1
To save time, here's a screenshot with the regex applied and the green portions selected as desired, so the regex seems to be working and recognizes the bundle id portion of the following examples as expected:
The issue I'm experiencing is that when using this regex with grep, grep -e, egrep, or sed it doesn't seem to be working in the same manner. I would like to use sed to run the string replacement and have tried the following methods to achieve this:
# variable definitions
BUNDLE_ID='mynew.bundle.id'
PBXFILE="$SRCROOT/myproject.xcodeproj/project.pbxproj"
# check if the test bundle id is currently in the file
if grep -Fq "REPLACEABLE_BUNDLE_ID" $PBXFILE; then
# this commented version works as expected as it's using simple string replacement
#sed -i '' "s/REPLACEABLE_BUNDLE_ID/$BUNDLE_ID/g" $PBXFILE
# these are the versions of the regex I've tried with sed #
# basic version working in validator & testing with sublime text regex engine
(?<=PRODUCT_BUNDLE_IDENTIFIER = )([a-zA-Z0-9_]+(?:\.[a-zA-Z0-9_]+){0,2})
# added extra parentheses around product id first portion
(?<=(PRODUCT_BUNDLE_IDENTIFIER = ))([a-zA-Z0-9_]+(?:\.[a-zA-Z0-9_]+){0,2})
# escaped version
\(?<=PRODUCT_BUNDLE_IDENTIFIER = \)\([a-zA-Z0-9_]+\(?:\.[a-zA-Z0-9_]+\){0,2}\)
# try replacing the current bundle id using the regex
sed -i -E '' "s/I put the regex here/$BUNDLE_ID/g" $PBXFILE
fi
I'm fairly new with regex and have not used sed before. I've read about extended regular expressions here: http://www.grymoire.com/Unix/Regular.html#uh-12 and feel like I'm just failing to put the pieces together properly.

Answer 1

Try this for GNU sed (use -E for unix):
$ sed -r "s/(PRODUCT_BUNDLE_IDENTIFIER = )[a-zA-Z0-9_]+(\.[a-zA-Z0-9_]+){0,2}/\1${BUNDLE_ID}/"
for example:
$ cat test.txt
PRODUCT_BUNDLE_IDENTIFIER = com.test.mybundle.keyboard;
PRODUCT_BUNDLE_IDENTIFIER = com.test.mybundle.iMessage;
PRODUCT_BUNDLE_IDENTIFIER = com.test;
PRODUCT_BUNDLE_IDENTIFIER = replaceable;
$ BUNDLE_ID='mynew.bundle.id'
$ sed -r "s/(PRODUCT_BUNDLE_IDENTIFIER = )[a-zA-Z0-9_]+(\.[a-zA-Z0-9_]+){0,2}/\1${BUNDLE_ID}/" test.txt
PRODUCT_BUNDLE_IDENTIFIER = mynew.bundle.id.keyboard;
PRODUCT_BUNDLE_IDENTIFIER = mynew.bundle.id.iMessage;
PRODUCT_BUNDLE_IDENTIFIER = mynew.bundle.id;
PRODUCT_BUNDLE_IDENTIFIER = mynew.bundle.id;