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Learning objective: (2) Explain the use of the GOTO command and labels in batch files
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The GOTO command allows the normal sequencing of events to jump to other locations in the batch file, either above or below the current location. If the jump is above the current location, the jump provides looping. If the jump is below the current location, the jump provides selection. A :label is the location of the jump. A label is any text, with no spaces, that starts with a colon like ":end". (Spaces act as delimiters.) In the event a batch file ends with an endless loop, you can use "Crtl+C" to stop the loop.
This batch file will generate an endless loop. When the batch file reaches the bottom, the GOTO command sends it to the loop label.
:label
The :label is a marker in the batch file that a GOTO command can jump to. The GOTO jump can either jump up to create looping or jump down for selection. During execution, if a :label is encountered, no action will be taken and processing will continue to the next line. It is good form to have a ":end" section at the bottom of the batch file to act as a termination point for the batch file.
GOTO label
GOTO label (note the reference to the label does NOT start with a ":" colon) will jump to that location in the batch file. If one is not careful, an endless loop can be created. If that occurs, a "Ctrl+C" should stop the runaway loop.
Thinking: What is the functional difference between jumping up or jumping down from a given location in the batch file?
Key terms: GOTO, end, endless loop, label
Resources:
To maximize your learning, please visit these Web sites and review their content
to help reinforce the concepts presented in this section.
Quick links:
GOTO @ ss64.com
GOTO command @ instructables.com
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GOTO @ ss64.com |
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GOTO command @ instructables.com |
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