dbrowcount man page
dbrowcount — count the number of rows in an Fsdb stream
Count the number of rows and write out a new fsdb file with one column (n) and one value: the number of rows. This program is a strict subset of dbcolstats.
Although there are other ways to get a count of rows (
"dbrowaccumulate -C 1" and some processing), counting is so common it warrants its own command. (For example, consider how often
"wc -l" is used in regular shell scripting.) There are some gross and subtle differences, though, in that
"dbrowcount" doesn't require one to specify a column to search, and it also doesn't look for and skip null data items.
No program-specific options.
This module also supports the standard fsdb options:
Enable debugging output.
- -i or --input InputSource
Read from InputSource, typically a file name, or
"-"for standard input, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.
- -o or --output OutputDestination
Write to OutputDestination, typically a file name, or
"-"for standard output, or (if in Perl) a IO::Handle, Fsdb::IO or Fsdb::BoundedQueue objects.
- --autorun or --noautorun
By default, programs process automatically, but Fsdb::Filter objects in Perl do not run until you invoke the run() method. The
"--(no)autorun"option controls that behavior within Perl.
Show full manual.
#fsdb absdiff 0 0.046953 0.072074 0.075413 0.094088 0.096602 # | /home/johnh/BIN/DB/dbrow # | /home/johnh/BIN/DB/dbcol event clock # | dbrowdiff clock # | /home/johnh/BIN/DB/dbcol absdiff
cat data.fsdb | dbrowcount
#fsdb n 6 # | /home/johnh/BIN/DB/dbrow # | /home/johnh/BIN/DB/dbcol event clock # | dbrowdiff clock # | /home/johnh/BIN/DB/dbcol absdiff
As another example, this input produces the same output as above in
"dbrowcount", but different output in
#fsdb absdiff - - - - - - # | /home/johnh/BIN/DB/dbrow # | /home/johnh/BIN/DB/dbcol event clock # | dbrowdiff clock # | /home/johnh/BIN/DB/dbcol absdiff
dbcolaccumulate(1), dbcolstats(1), Fsdb(3)
AUTHOR and COPYRIGHT
Copyright (C) 2007-2015 by John Heidemann <email@example.com>
This program is distributed under terms of the GNU general public license, version 2. See the file COPYING with the distribution for details.