Flex is a tool for generating scanners, programs which recognized
lexical patterns in text.  Flex reads the given input files, or its
standard input if no file names are given, for a description of a
scanner to generate.  The description is in the form of pairs of
regular expressions and C code, called rules.  Flex generates as
output a C source file, lex.yy.c, which defines a routine yylex().
This file is compiled and linked with the -lfl library to produce an
executable.  When the executable is run, it analyzes its input for
occurrences of the regular expressions.  Whenever it finds one, it
executes the corresponding C code.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
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-rw-rw-r-- 20025/200    184990  450560  41.1% -lh5- 758b Mar 30  1998 flex-2.5.4-bin.tar
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 Total         1 file   184990  450560  41.1%            Mar 16  1998