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CONSOLE stage v1.2
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Pipelines v1.9
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>>__CONSole__ ____________ __ _______________________ _________________________________><
|_EOF_string_| |_DELIMpair_char1,char2_|
(1) (2)
Notes:
(1) May only be specified when console is the first stage of the first pipeline.
(2) May only be specified when console is not the first stage of a pipeline.
Use the CONSOLE
stage to read lines from the keyboard or write lines to the console.
When CONSOLE is
the first stage of the first pipeline; CONSOLE reads records from the keyboard
and writes them to its primary output stream. CONSOLE stops reading if its primary
output stream becomes disconnected. If no operands are specified, CONSOLE stops
reading when a null line is entered from the keyboard. To enter a null line,
press <enter> without typing anything on the command-line.
When CONSOLE is
not the first stage of a pipeline; CONSOLE reads records from its primary input
stream and writes them to the console and to its primary output stream, if it
is connected. CONSOLE appends a Line-Feed character to each output record that
it writes to the console, primary output stream records are written unchanged.
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EOF
specifies that CONSOLE is to stop reading from the keyboard when the input
text matches string.
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string
is a string that you want CONSOLE to recognise as a signal to stop
reading from the keyboard. The string
is not written to the output stream. Uppercase and lowercase
representations of the same characters do not match. CONSOLE stops reading
from the keyboard if the line read matches the target string you specify.
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DELIMpair
specifies that records written to the console are prefixed and
appended with a pair of delimiting characters. The CONSOLE stage only uses
the delimiting characters when writing the record to the console, they are
not included in the record written to the primary output stream.
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char1
char2
are a pair of characters that will surround the record
displayed on the console.
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For example: to display a record
surrounded by a leading > and trailing <:
. . . console delimpair >,< . . .
The following streams are used by the CONSOLE
stage:
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Stream
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Action
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Primary input
stream
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When CONSOLE is not the first stage of the
pipeline, CONSOLE reads records from its primary input stream.
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Primary output
stream
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When CONSOLE is the first stage of the first pipeline, CONSOLE writes
the records it reads from the keyboard to its primary output stream. When
CONSOLE is not the first stage of the pipeline, CONSOLE writes the records it
reads from its primary input stream to its primary output stream.
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1)
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CONSOLE
does not delay the records.
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2)
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When
CONSOLE is the first stage of the first pipeline and it discovers that its
primary output stream is not connected, the CONSOLE stage ends.
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3)
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CONSOLE may stop reading from the keyboard
before the condition specified in the operands is satisfied. If a stage that
reads records which flow out of the CONSOLE stage, ends or disconnects its
input stream, the CONSOLE stage ends; as in the following example: The first
CONSOLE stage stops reading from the keyboard after the second line of data
or a null has been entered. (The TAKE stage reads exactly 2 records and then
disconnects is primary input stream; causing the primary output stream of the
CONSOLE stage to become disconnected; which terminates the stage).
C:\>pipe “console | take
2 | console”
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4)
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When the pipe
TRACE ON option is specified (or the pipeline has inherited the TRACE ON
setting through the CALLPIPE stage command); the CONSOLE stage encloses it’s
console output in angle brackets – prefixed with the CONSOLE stage name. For
example:
CONSOLE: >some
output text<
However; the CONSOLE stage only uses this output format
when writing a record to the console; records that are written to the primary
output stream are written without modification.
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5)
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CONSOLE verifies
that its secondary input and output streams are not connected and then begins
execution.
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None.
Reference
the following links for additional information:
IN, OUT