Thedward questions

Thedward answers

• Escape PCRE metacharacters in Haskell
• in bash find all files in flat directory that don't exist in another directory tree
• Getting the count of unique values in a column in bash
• Random number between range in shell
• Is there a better way to convert from UTCTime to EpochTime?
• How can I tell if a jq filter successfully pulls data from a JSON data structure?