1Fsdb::Filter::dbrowcounUts(e3r)Contributed Perl DocumentFastdibo:n:Filter::dbrowcount(3)
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NAME

6       dbrowcount - count the number of rows in an Fsdb stream
7

SYNOPSIS

9       dbrowcount
10

DESCRIPTION

12       Count the number of rows and write out a new fsdb file with one column
13       (n) and one value: the number of rows.  This program is a strict subset
14       of dbcolstats.
15
16       Although there are other ways to get a count of rows ("dbcolstats", or
17       "dbrowaccumulate -C 1" and some processing), counting is so common it
18       warrants its own command.  (For example, consider how often "wc -l" is
19       used in regular shell scripting.)  There are some gross and subtle
20       differences, though, in that "dbrowcount" doesn't require one to
21       specify a column to search, and it also doesn't look for and skip null
22       data items.
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OPTIONS

25       No program-specific options.
26
27       This module also supports the standard fsdb options:
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29       -d  Enable debugging output.
30
31       -i or --input InputSource
32           Read from InputSource, typically a file name, or "-" for standard
33           input, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue
34           objects.
35
36       -o or --output OutputDestination
37           Write to OutputDestination, typically a file name, or "-" for
38           standard output, or (if in Perl) a IO::Handle, Fsdb::IO or
39           Fsdb::BoundedQueue objects.
40
41       --autorun or --noautorun
42           By default, programs process automatically, but Fsdb::Filter
43           objects in Perl do not run until you invoke the run() method.  The
44           "--(no)autorun" option controls that behavior within Perl.
45
46       --help
47           Show help.
48
49       --man
50           Show full manual.
51

SAMPLE USAGE

53   Input:
54           #fsdb      absdiff
55           0
56           0.046953
57           0.072074
58           0.075413
59           0.094088
60           0.096602
61           #  | /home/johnh/BIN/DB/dbrow
62           #  | /home/johnh/BIN/DB/dbcol event clock
63           #  | dbrowdiff clock
64           #  | /home/johnh/BIN/DB/dbcol absdiff
65
66   Command:
67           cat data.fsdb | dbrowcount
68
69   Output:
70           #fsdb n
71           6
72           #  | /home/johnh/BIN/DB/dbrow
73           #  | /home/johnh/BIN/DB/dbcol event clock
74           #  | dbrowdiff clock
75           #  | /home/johnh/BIN/DB/dbcol absdiff
76
77   Input 2:
78       As another example, this input produces the same output as above in
79       "dbrowcount", but different output in "dbstats":
80
81           #fsdb      absdiff
82           -
83           -
84           -
85           -
86           -
87           -
88           #  | /home/johnh/BIN/DB/dbrow
89           #  | /home/johnh/BIN/DB/dbcol event clock
90           #  | dbrowdiff clock
91           #  | /home/johnh/BIN/DB/dbcol absdiff
92

SEE ALSO

94       dbcolaccumulate(1), dbcolstats(1), Fsdb(3)
95

CLASS FUNCTIONS

97   new
98           $filter = new Fsdb::Filter::dbrowcount(@arguments);
99
100   set_defaults
101           $filter->set_defaults();
102
103       Internal: set up defaults.
104
105   parse_options
106           $filter->parse_options(@ARGV);
107
108       Internal: parse options
109
110   setup
111           $filter->setup();
112
113       Internal: setup, parse headers.
114
115   run
116           $filter->run();
117
118       Internal: run over all IO
119
120   finish
121           $filter->finish();
122
123       Internal: write trailer.
124

126       Copyright (C) 2007-2022 by John Heidemann <johnh@isi.edu>
127
128       This program is distributed under terms of the GNU general public
129       license, version 2.  See the file COPYING with the distribution for
130       details.
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134perl v5.38.0                      2023-07-20       Fsdb::Filter::dbrowcount(3)
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