Date: Tue, 2 Jul 2002 01:05:53 -0500 From: Bob Willcox <bob@immure.com> To: questions list <freebsd-questions@freebsd.org> Subject: awk getline question/odditiy Message-ID: <20020702060553.GA72170@luke.immure.com>
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I noticed tonight that awk (this includes gawk, nawk, and mawk) won't
re-execute a command once it has run it once. For example this simple
program (called exmpl later on):
#!/usr/bin/awk -f
{
while ($0 | getline line > 0)
print line
}
Running the program with some simple input you get:
bob@luke:pl /home/bob/work/local/src/linux_dbg> ./exmpl
ps -T
PID TT STAT TIME COMMAND
37977 pl Ss 0:00.19 ksh
72370 pl S+ 0:00.03 /usr/bin/awk -f ./exmpl
72377 pl S+ 0:00.00 sh -c ps -T
72378 pl R+ 0:00.00 ps -T
ps -T
ps -T
PID TT STAT TIME COMMAND
37977 pl Ss 0:00.19 ksh
72370 pl S+ 0:00.03 /usr/bin/awk -f ./exmpl
72377 pl Z+ 0:00.00 (sh)
72389 pl S+ 0:00.02 sh -c ps -T
72390 pl R+ 0:00.01 ps -T
Notice that the second attempt to run "ps -T" produces no output
whereas specifying it as "ps -T" (two spaces between the command and
flag) causes it to run. I tried a number of combinations and awk was
consistent in _never_ executing the exact same command string more than
once.
Is there some way to override this behavior? I couldn't find any
mention of it in the man page or "The Awk Programming Language" by Aho,
Kernighan, & Weinberger.
Thanks,
Bob
--
Bob Willcox Vital papers will demonstrate their vitality by
bob@vieo.com spontaneously moving from where you left them to where
Austin, TX you can't find them.
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