re = /(?<=:\s).*/m
str = 'Turning on API signature validation for service : PGL
Turning off API signature validation for service : PLATFORM
Turning off API signature validation for service : WEBWORKS
Turning on API signature validation for service : TIMER_SINK
Turning on API signature validation for service : MESSAGING
Turning on API signature validation for service : EMAIL
Turning off API signature validation for service : USER_SECURITY
Initializing MDM for :USER_SECURITY
<MDM/>'
subst = '$1'
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html