Is it possible to extract a package.json version value in a bamboo task? I want to extract the version field and save its value in a bamboo.variable.
Yes, try adding "Script" task into your Bamboo Job. In the script body you can add a code to read package.json version by using grep function from cat command output, and assign to a variable you like, e.g. PACKAGE_VERSION:
# Version key/value should be on his own line
PACKAGE_VERSION=$(cat package.json \
| grep version \
| head -1 \
| awk -F: '{ print $2 }' \
| sed 's/[",]//g')
echo $PACKAGE_VERSION