Number-to-string conversion, testing assertions, rounding, random number generation, converting characters to numbers, joining strings, getting easily usable time-of-day information, and reading a whole file in one shot
Noting data file boundaries, rereading the current file, checking for readable files, checking for zero-length files, and treating assignments as file names
An awk version of the standard C getopt() function
Two sets of routines that parallel the C library versions
Two functions that traverse an array of arrays to any depth