awk has saved my backside on more occasions than I can remember. pcregrep is another surprisingly powerful command line tool. Very useful for extracting json with nested data structures from logs. GNU grep is more or less as powerful via the -P (pcre) flag. Another underrated command line tool is the venerable POSIX look command. It is able to perform binary searches on lexically sorted files. Very useful for quickly zeroing in on slices of interest from ginormous log files where each line is prefixed with an ISO timestamp.