The No Version; Run And Do Commands - Juniper SYSTEM BASICS - CONFIGURATION GUIDE V 11.1.X Configuration Manual

Chapter 2: Command-Line Interface

The no Version

With very few exceptions, every system configuration command has a no version,
which you can use to negate a command (or a portion of it as specified by an optional
keyword) or to restore its default setting. When you use a command without the
keyword no, you can reenable a disabled feature or override a default setting.
You have the option of using the default keyword whenever the no keyword is also
a choice; simply enter the keyword default instead of no.
In most cases, when you execute the default version of a command, it produces the
exact results as the no version. There are some commands for which the default
version yields a different result from the no version.
Commands for which the default behavior differs from the no behavior are clearly
identified in the JUNOSe Command Reference Guide. Unless otherwise specified,
therefore, the default command is identical to the no command and is neither
documented nor discussed.
The syntax for each no command is described in the JUNOSe Command Reference
Guide. The few system configuration commands that do not have a no version are
indicated in the individual command description.
Because show commands are for the purpose of monitoring your configurations,
they do not have no versions. Most User Exec and Privileged Exec mode commands
do not have no versions.
The CLI can act on no versions of commands when you have entered sufficient
information to distinguish the command syntactically; the CLI ignores all subsequent
input on that line.
To be compatible with some non-Juniper Networks implementations, the no versions
of commands will accept the same options as the affirmative version of the
commands. The CLI ignores the optional input if it has no effect on the command
behavior. If using the option changes the behavior of the no version, the individual
command entry in this guide describes the difference in behavior.

run and do Commands

You can run Exec mode commands while in any configuration mode by preceding
the command with the keyword run or do. For example:
host1(config)#run show users
NOTE: The run and do commands are interchangeable.
By using the run or do command in this way, you can obtain show command
information without leaving configuration mode.
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Overview