Configuration Fundamentals Configuration Guide, Cisco IOS Release 15.0S

Contextual Configuration Diff Utility

The Contextual Configuration Diff Utility feature provides the ability to perform a line-by-line comparison of any two configuration files (accessible through the Cisco IOS Integrated File System [IFS]) and generate a list of the differences between them. The generated output includes information regarding configuration lines that have been added, modified, or deleted, and the configuration modes within which a changed configuration line exists.

Finding Feature Information in This Module

Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Contextual Configuration Diff Utility" section.

Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Contents

•Prerequisites for Contextual Configuration Diff Utility

•Restrictions for Contextual Configuration Diff Utility

•Information About Contextual Configuration Diff Utility

•How to Use the Contextual Configuration Diff Utility

•Configuration Examples for the Contextual Configuration Diff Utility

•Additional References

•Command Reference

•Feature Information for Contextual Configuration Diff Utility

Prerequisites for Contextual Configuration Diff Utility

The format of the configuration files used for the Contextual Configuration Diff Utility feature must comply with standard Cisco IOS configuration file indentation rules as follows:

•Start all commands on a new line with no indentation, unless the command is within a configuration submode.

•Indent commands within a first-level configuration submode one space.

•Indent commands within a second-level configuration submode two spaces.

•Indent commands within subsequent submodes accordingly.

The router must have a contiguous block of memory larger than the combined size of the two configuration files being compared.

Restrictions for Contextual Configuration Diff Utility

If the router does not have a contiguous block of memory larger than the combined size of the two configuration files being compared, the diff operation fails.

Information About Contextual Configuration Diff Utility

Before using the Contextual Configuration Diff Utility feature, you should understand the following concepts:

•Benefits of the Contextual Configuration Diff Utility

•Contextual Configuration Diff Utility Output Format

Benefits of the Contextual Configuration Diff Utility

The Contextual Configuration Diff Utility feature provides the ability to perform a line-by-line comparison of any two configuration files (accessible through the Cisco IOS File System [IFS]) and generate a list of the differences between them. The generated output includes information regarding the following items:

•Configuration lines that have been added, modified, or deleted.

•Configuration modes within which a changed configuration line exists.

•Location changes of configuration lines that are order-sensitive. For example, the ip access-list and community-lists commands are order-sensitive commands dependent on where they are listed within a configuration file in relation to other Cisco IOS commands of similar type.

Contextual Configuration Diff Utility Output Format

Diff Operation

The Contextual Configuration Diff Utility feature uses the filenames of two configuration files as input. A diff operation is performed on the specified files and a list of differences between the two files is generated as output. Interpreting the output is dependent on the order in which the two files are configured (show archive config differences command). In this section, we assume that the filename of the file entered first is file1 and the filename of the file entered second is file2. Each entry in the generated output list is prefixed with a unique text symbol to indicate the type of difference found. The text symbols and their meanings are as follows:

•A minus symbol (-) indicates that the configuration line exists in file1 but not in file2.

•A plus symbol (+) indicates that the configuration line exists in file2 but not in file1.

•An exclamation point (!) with descriptive comments is used to identify order-sensitive configuration lines whose location is different in file1 than in file2.

Incremental Diff Operation

Some applications require that the generated output of a diff operation contain configuration lines that are unmodified (in other words, without the minus and plus symbols). For these applications, an incremental diff operation can be performed, which compares a specified configuration file to the running configuration file (show archive config incremental-diffs command).

When an incremental diff operation is performed, a list of the configuration lines that do not appear in the running configuration file (in other words, configuration lines that only appear in the specified file that is being compared to the running configuration file) is generated as output. An exclamation point (!) with descriptive comments is used to identify order-sensitive configuration lines whose location is different in the specified configuration file than in the running configuration file.

How to Use the Contextual Configuration Diff Utility

This section provides the following procedure:

•Using the Contextual Configuration Diff Utility (required)

Using the Contextual Configuration Diff Utility

This task describes how to use the Contextual Configuration Diff Utility feature.

SUMMARY STEPS

1. enable

2. show archive config differences [file1 [file2]]
or
show archive config incremental-diffs [file]

3. exit

DETAILED STEPS

Configuration Examples for the Contextual Configuration Diff Utility

This section contains the following configuration examples:

•Diff Operation: Example

•Incremental Diff Operation: Example

Diff Operation: Example

In this example, a diff operation is performed on the running and startup configuration files. Table 1 shows the configuration files used for this example.

The following is sample output from the show archive config differences command. This sample output displays the results of the diff operation performed on the configuration files in Table 1.

Router# show archive config differences running-config startup-config

+ip subnet-zero

+ip name-server 10.4.4.4

+voice dnis-map 1

 +dnis 111

interface Ethernet1/0

 +no ip address

 +shutdown

+ip default-gateway 10.5.5.5

+ip classless

+access-list 110 deny ip any host 10.1.1.1

+access-list 110 deny ip any host 10.1.1.2

+access-list 110 deny ip any host 10.1.1.3

+snmp-server community private RW

-no ip subnet-zero

interface Ethernet1/0

 -ip address 10.7.7.7 255.0.0.0

-no ip classless

-snmp-server community public RO

Incremental Diff Operation: Example

In this example, an incremental diff operation is performed on the startup and running configuration files. Table 2 shows the configuration files used for this example.

The following is sample output from the show archive config incremental-diffs command. This sample output displays the results of the incremental diff operation performed on the configuration files in Table 2.

Router# show archive config incremental-diffs startup-config

ip subnet-zero

ip name-server 10.4.4.4

voice dnis-map 1

 dnis 111

interface Ethernet1/0

 no ip address

 shutdown

ip default-gateway 10.5.5.5

ip classless

 access-list 110 deny ip any host 10.1.1.1

 access-list 110 deny ip any host 10.1.1.2

 access-list 110 deny ip any host 10.1.1.3

snmp-server community private RW

Additional References

This section provides references related to the Contextual Configuration Diff Utility feature.

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Configuration Fundamentals Command Reference at http://www.cisco.com/en/US/docs/ios/fundamentals/command/reference/cf_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.

•show archive config differences

•show archive config incremental-diffs

Feature Information for Contextual Configuration Diff Utility

Table 3 lists the release history for this feature.

Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.

Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

Note Table 3 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release. Unless noted otherwise, subsequent releases of that Cisco IOS software release also support that feature.

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