Outputs the unique lines from all the input files.
Processes the lines in each input file. All lines are added to an associated array.
The first time a line is seen it is output. If key fields are being used these are
used as the basis for the associative array entries rather than the full line.
Outputs the unique lines from all the input files.
Processes the lines in each input file. All lines are added to an associated array. The first time a line is seen it is output. If key fields are being used these are used as the basis for the associative array entries rather than the full line.