Cisco IOS Command Tips and Tricks – 3 Command Line Habits a CCNA Network Engineer Should Have

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Whether or not you’ve still in the process of CCNA preparation or are already working as a CCNA certified network engineer, it’s best to form good command line habits as early as possible. Even with many GUI configuration tools, most Cisco network engineers still spend a lot of time in the Cisco IOS command-line interface. For many tasks, it’s simply much faster to use the command-line. The below 3 habits and associated Cisco IOS commands are essential for any networks engineer. The earlier you start doing these, the better. A good place to start would be at your home lab (if you have one).

Always Save Your Configuration

After doing any configuration to the Cisco IOS router and switch, and verifying that the configuration change was good, the configuration should be saved to the startup configuration. Please note that (most) configuration changes take place almost immediately, however in case of power loss or in the rare event that your device crashes, you’ll want the device to have the latest configuration. The command used in most CCNA preparation books and CCNA materials is “copy running-configuration startup-configuration” or “copy run start” for short.

One extremely useful tip here is that the older command “wr” and “wr mem” almost always works and is much easier to type and to remember to do (see below). However please note that the “wr” commands are not available when you are attempting the actual CCNA test and are doing the simulation questions in the test.

Router#wr Building configuration... [OK] Router# Router#wr ? core Write Core File erase Erase NV memory memory Write to NV memory mib-data Write MIB persistence data to NV memory network Write to network TFTP server terminal Write to terminal

Router#wr

Always Backup Your Configuration

By backing up your configuration I mean to copy the running configuration off the network device. In terms of data redundancy you should always have a copy of the configuration somewhere else. The easiest way to do this is via TFTP. Various free TFTP servers are available for all platforms.

Stay Out of Enable Mode – Unless Necessary

All network engineers should be careful when entering privileged mode in the Cisco IOS command-line interface. One thing I have seen CCNA network engineers do is to make going into and staying in enable mode a habit. In my opinion, this is extremely dangerous as you are allowed to execute practically any command in privileged mode. A typical network engineer would be logged into several devices at once. To safeguard against the possibility that you accidentally copy and paste text (while in enable mode), you should make it a habit to exit enable mode once you are done executing any command that require that level of access. The command to do this is “disable“.