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早期freebsd实现

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Copyright (C) AT&T 1993
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This is the version of awk described in "The AWK Programming Language",
by A. V. Aho, B. W. Kernighan, and P. J. Weinberger
(Addison-Wesley, 1988, ISBN 0-201-07981-X).
Changes, mostly bug fixes, are listed in FIXES.
If you distribute this code further, please please please
distribute FIXES with it.  If you find errors, please report
them to [e-mail].  Thanks.

The program itself is created by
	make
which should produce a longish sequence of
messages roughly like this:

	yacc -d awk.g.y
	
	conflicts: 43 shift/reduce, 85 reduce/reduce
	cc -g  -c y.tab.c
	rm y.tab.c
	mv y.tab.o awk.g.o
	cmp -s y.tab.h prevy.tab.h || (cp y.tab.h prevy.tab.h; echo change maketab)
	prevy.tab.h: No such file or directory
	change maketab
	lex  awk.lx.l
	cc -g  -c lex.yy.c
	rm lex.yy.c
	mv lex.yy.o awk.lx.o
	cc -g  -c b.c
	cc -g  -c main.c
	cc -g  -c parse.c
	cc maketab.c -o maketab
	./maketab >proctab.c
	cc -g  -c proctab.c
	cc -g  -c tran.c
	cc -g  -c lib.c
	cc -g  -c run.c
	cc -g  awk.g.o awk.lx.o b.o main.o parse.o proctab.o tran.o lib.o run.o    -lm

This produces an executable a.out;  you will eventually
want to move this to some place like /usr/bin/awk.

The -g option (which generates symbol table information
for debuggers) can be disabled by removing the line
	CFLAGS = -g
from the makefile.  Alternatively, you might replace
it by
	CFLAGS = -O
if your compiler does significant optimization.

NOTE: This version uses ANSI C, as you should also.