Grep
From Andreida
It depends on your linux/grep, how you have to build your regular expressions.
Search for letter/digit combinations of a certain length
grep -oe '[[:alnum:]]\{17\}' my_data.txt
E-Mail addresses
grep -E -o "\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,6}\b" rejectlog* | sort -u
