dbfilediff - Man Page

compare two fsdb tables

Synopsis

    dbfilediff [-Eq] [-N diff_column_name] --input table1.fsdb --input table2.fsdb

OR

    cat table1.fsdb  | dbfilediff [-sq] --input table2.fsdb

Description

Dbfilediff compares two Fsdb tables, row by row. Unlike Unix diff(1), this program assumes the files are identical line-by-line and we compare fields. Thus, insertion of one extra row will result in all subsequent lines being marked different.

By default, all columns must be unique. (At some point, support to specific specific columns may be added.)

Output is a new table with a new column diff (or something else if the -N option is given), "-"  and "+" for the first and second non-equal rows, "=" for matching lines,  or "~" if they are equal with epsilon numerics (in which case only the second row is included). Unlike Unix diff(1), we output all rows (the "=" lines), not just diffs (the --quiet option suppresses this output).

Optionally, with -E it will do a "epsilon numeric" comparision, to account for things like variations in different computer's floating point precision and differences in printf output.

Epsilon comparision is asymmetric, in that it assumes the first input is correct an allows the second input to vary, but not the reverse.

Because two tables are required, input is typically in files. Standard input is accessible by the file "-".

Options

-E or --epsilon

Do epsilon-numeric comparison. (Described above.)

Epsilon-comparision is only done on columns that look like floating point numbers, not on strings or integers. Epsilon comparision allows the last digit to vary by 1, or for there to be one extra digit of precision, but only for floating point numbers.

Rows that are within epsilon are not considered different  for purposes of the exit code.

--exit

Exit with a status of 1 if some differences were found. (By default, the exit status is 0 with or without differences if the file is processed successfully.)

-N on --new-name

Specify the name of the diff column, if any. (Default is diff.)

-q or --quiet

Be quiet, suppressing output for identical rows. (This behavior is different from Unix diff(1)  where -q suppresses all output.) If repeated, omits epsilon-equivalent rows.

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 event clock absdiff pctdiff
    _null_getpage+128   815812813.281756        0       0
    _null_getpage+128   815812813.328709        0.046953        5.7554e-09
    _null_getpage+128   815812813.353830        0.025121        3.0793e-09
    _null_getpage+128   815812813.357169        0.0033391       4.0929e-10

And in the file TEST/dbfilediff_ex.in-2:

    #fsdb event clock absdiff pctdiff
    _null_getpage+128   815812813.281756        0       0
    _null_getpage+128   815812813.328709        0.046953        5.7554e-09
    _null_getpage+128   815812813.353830        0.025121        3.0793e-09
    _null_getpage+128   815812813.357169        0.003339        4.0929e-10

Command

    cat TEST/dbfilediff_ex.in | dbfilediff -i - -i TEST/dbfilediff_ex.in-2

Output

    #fsdb event clock absdiff pctdiff diff
    _null_getpage+128   815812813.281756        0       0       =
    _null_getpage+128   815812813.328709        0.046953        5.7554e-09      =
    _null_getpage+128   815812813.353830        0.025121        3.0793e-09      =
    _null_getpage+128   815812813.357169        0.0033391       4.0929e-10      -
    _null_getpage+128   815812813.357169        0.003339        4.0929e-10      +
    #   | dbfilediff --input TEST/dbfilediff_ex.in-2

By comparision, if one adds the -s option, then all rows will pass as equal.

See Also

Fsdb. dbrowuniq. dbfilediff.

dbrowdiff, dbrowuniq, and dbfilediff are similar but different. dbrowdiff computes row-by-row differences for a column, dbrowuniq eliminates rows that have no differences, and dbfilediff compares fields of two files.

Info

2024-08-02 perl v5.40.0 User Contributed Perl Documentation