Rdb: Ruby-Nachbau der MWC /rdb-Werkzeuge

man/difference.man

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+.TH difference "" "" "/rdb Command"
+.PC "Output table of rows that are in only one table"
+\fBdifference \fItable1 table2\fR
+.PP
+.II table^difference
+.II table^subtract
+.II "subtract tables"
+.II sort
+.II uniq
+The command
+.B difference
+uses the COHERENT commands
+.B sort
+and
+.B uniq
+to subtract logically
+.I table2
+from
+.IR table1 .
+Its output consists of the rows that are in
+.I table1
+but not in
+.IR table2 .
+The two input tables must have the same columns
+(\fIunion compatible\fR in the technical data-base literature),
+and the rows must be exactly identical \(em including every space, tab,
+and nonprinting character.
+If two rows look the same to you but not to
+.BR difference ,
+try the
+.B see
+command to discover any blank spaces and nonprinting characters.
+.SH Example
+In this example, consider the table
+.BR journal ,
+which appears as follows:
+.DM
+Date    Amount  Account Ref     Description
+------- ------- ------- ------- --------------------------------
+820107    14.00 meal    v       meal with jones
+820113   101.62 car     v       car repairs
+820114    81.80 insur   c       car insurance allstate
+820114    93.00 car     c       car registration dmv
+820119    81.72 vitamin c       sundown vitamins
+820121    20.83 meal    v       meal with scott
+820121  2500.00 keogh   c       keogh payment
+820125    99.00 dues    v       dues to uni-ops unix conference
+.DE
+.PP
+And consider the table
+.BR carexpense ,
+which appears as follows:
+.DM
+Date    Amount  Account Ref     Description
+------- ------- ------- ------- --------------------------------
+820113   101.62 car     v       car repairs
+820114    81.80 insur   c       car insurance allstate
+820114    93.00 car     c       car registration dmv
+.DE
+.PP
+The command
+.DM
+	difference journal carexpense
+.DE
+.PP
+logically ``subtracts''
+.B carexpense
+from
+.BR journal ,
+to produce the following output:
+.DM
+Date    Amount  Account Ref     Description
+------- ------- ------- ------- --------------------------------
+820107    14.00 meal    v       meal with jones
+820119    81.72 vitamin c       sundown vitamins
+820121    20.83 meal    v       meal with scott
+820121  2500.00 keogh   c       keogh payment
+820125    99.00 dues    v       dues to uni-ops unix conference
+.DE
+.SH "See Also"
+COHERENT Lexicon:
+.B
+diff,
+diff3,
+sort,
+uniq
+.R
+.SO difference