Chapter 45: CLI Overview
STANDARD Revision 1.0 C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved. 1121
This is another use for the ^ symbol. In this example, the following regular expression matches an input string only if the
string starts with 1234:
^1234
The next example shows that the following regular expression is a range that matches any single number, as long as it is
not the numbers 1, 2, 3, or 4:
[^1234]
Parentheses for Recall
You can use parentheses () with multiple-character regular expressions to multiply the occurrence of a pattern. You can
also use parentheses around a single or multiple-character pattern to instruct the software to remember a pattern for use
elsewhere in the regular expression.
To create a regular expression that recalls a previous pattern, you use parentheses to instruct memory of a specific pattern
and a backslash (\) followed by an integer to reuse the remembered pattern. The integer specifies the occurrence of a
parentheses in the regular expression pattern. If you have more that one remembered pattern in your regular expression,
then \1 uses the first remem\-bered pattern and \2 uses the second remembered pattern, up to nine.
The following regular expression uses parentheses for recall:
a(.)bc(.)\1\2
This regular expression matches the letter a followed by any character (call it character #1) followed by bc, followed by any
character (character #2), followed by character #1 again, followed by character #2 again. In this way, the regular
expression could match azbctzt. The software identified character #1 as z and character #2 as t and then uses z and t again
later in the regular expression.
As you will notice, the parentheses do not change the pattern; they only instruct the software to recall that part of the
matched string.
Following is an example of advanced regular expression using double parentheses:
((19.*) (slot|interface))
CLI Repeat Command
The repeat CLI command will provide a single command to allow users to repeat a show command multiple times with an
optional delay in between shows.
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