dbrowcount - count the number of rows in an Fsdb stream

NOTE: this page was directly converted from the perl FSDB manual pages from FSDB version 3.1

SYNOPSIS

dbrowcount

DESCRIPTION

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 (dbcolstats, or 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.

OPTIONS

No program-specific options.

This module also supports the standard fsdb options:

-d

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.

--help

Show help.

--man

Show full manual.

SAMPLE USAGE

Input:

#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

Command:

cat data.fsdb | dbrowcount

Output:

#fsdb n 6 # | /home/johnh/BIN/DB/dbrow # | /home/johnh/BIN/DB/dbcol event clock # | dbrowdiff clock # | /home/johnh/BIN/DB/dbcol absdiff

Input 2:

As another example, this input produces the same output as above in dbrowcount, but different output in dbstats:

#fsdb absdiff - - - - - - # | /home/johnh/BIN/DB/dbrow # | /home/johnh/BIN/DB/dbcol event clock # | dbrowdiff clock # | /home/johnh/BIN/DB/dbcol absdiff

SEE ALSO

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