Use this "cheat sheet" as a quick reference and practical aid to efficent use of ClearCase. Tips, reminders, and expert advice to address the most common user needs.

Tom Milligan, Software configuration specialist, IBM Rational

Tom MilliganTom J. Milligan is a software configuration management specialist in IBM Rational's worldwide technical marketing department. Previously, as a member of Rational's western region consulting organization, he assisted Rational ClearCase and Rational ClearQuest customers. He has also worked in development roles ranging from programming to QA, tools acquisition, and system administration.



24 November 2003

Use this "cheat sheet" as a quick reference and practical aid to efficent use of IBM Rational® ClearCase®. Tips, reminders, and expert advice from one of Rational's in-house ClearCase pros answer the most common user needs.

Views


How many Views do I need?

Generally, one per discrete task is a good idea, though this is not a requirement. Views should be regarded as "cheap" entities that are easily created and destroyed. Create one for each task you need to do and when that task is done, delete the view.

Dynamic versus Snapshot Views

ClearCase and ClearCase LT offer snapshot views as workspaces. Snapshot views work by copying versions of elements from VOBs to your computer. To see the latest versions of elements, you need to update your snapshot view periodically. An update operation copies the latest versions of elements from the VOB to your view.

ClearCase (but not ClearCase LT) also offers dynamic views. A dynamic view uses the Multiversion File System (MVFS) to provide immediate, transparent access to data stored in VOBs. When you work in a dynamic view, you do not need to copy data fromVOBs to your view; you always see the latest versions of elements. Dynamic views also provide advanced functionality such as build auditing and binary sharing.

How to create a Dynamic View

cleartool mkview -tag atag  storage-location

Where atag is the view-tag (the "name" of the view which should be a name that you can easily remember) and storage-location is the location of a place on a disk where the view can store information.

Alternatively, there is a simplified command:

cleartool mkview -tag atag -stgloc -auto

In this example, you don't need to specify a storage location, but rather this command enables you to use a storage location that has been set up by your ClearCase admin.

How to delete a Dynamic View

cleartool rmview -tag atag

Where atag is the view-tag of the view you want to remove.

How to create a Snapshot View

cleartool mkview -snapshot -tag atag -stgloc -auto apathname

Where apathname is the path to which you want your source code (work area) to reside. The -tag atag is optional - if you omit it, ClearCase will make one up based on your username and the workspace you specify in apathname.

How to delete a Snapshot View

cleartool rmview apathname

Where apathname is the path to where your source code (work area) resides.


Modifying files


Checkout

To modify an element you need to check it out. Do this with the following command:

cleartool co anelement

where anelement is the name of the file or directory you want to check out.

Checkin

Once you are happy with the changes you have made to a checked-out element, you can check it in with the following command:

cleartool ci anelement

where anelement is the name of the file or directory you want to check in. Once you check-in an element, the changes you made to that element are usable by everyone on your project.

Uncheckout

If you want to cancel a checkout, you can do so with the following command:

cleartool unco anelement

where anelement is the name of the file or directory you want to check in.


Creating new files


Creation

To create a new file, you can use whatever editor or command you would normally use to create the file. The new file will be a view-private entity until you take the next step to put it under ClearCase control.

Putting a file under version control

To put a file under ClearCase control you must first check-out the directory that will be containing the file, issue the command to tell ClearCase to put the file under version control, and then check-in the directory containing the new file. Here are commands to perform these steps:

cleartool co thedirectory 
cleartool mkelem thefile 
cleartool ci thedirectory

After this sequence is performed, the file thefile is still checked-out and can be modified further before you check it in.


Deleting elements

To remove an element you should use the cleartool rmname command. This command removes the name of the specified element from the directory in which it is contained. Similar to placing an element under ClearCase control, you must first check-out the directory containing the element to be removed, do the cleartool rmname of the element, and then check-in the new version of the directory. Here is an example:

cleartool co thedirectory 
cleartool rmname anelement 
cleartool ci thedirectory

After this sequence, anelement is no longer listed in subsequent versions of thedirectory. It is, however, still listed in previous versions of the directory. If, at a later date you want to re-add anelement to a new version of thedirectory (or any other directory), you can do so easily.


Renaming elements

Renaming an element is similar to deleting it. First you check-out the old directory containing the element, and you also check-out the new directory to which the element is to be moved. Then you use the cleartool mv command to perform the move operation. Be sure to check-in the old and new directories when you are done.

cleartool co . 
cleartool co newdirectory 
cleartool mv anelement newdirectory 
cleartool ci . 
cleartool ci newdirectory

Renaming an element is also accomplished using the cleartool mv command except the old directory and the new directory are the same.

cleartool co . 
cleartool mv anelement anewname 
cleartool ci .

In subsequent versions of the directory, the name anelement will not appear, having been replaced by anewname but the name anelement will still appear in prior versions of the directory. Both the names anewname and anelement will still refer to the same element; only the name associated with the element in the directory will have changed.


Getting information


More about Views

What View am I in?

At any given time you can tell what view you are in by issuing the following command:

cleartool pwv

pwv means "print working view" in the tradition of the UNIX command pwd for "print working directory"

What is my "config-spec"?

Recall that a configuration specification (config-spec) is the set of rules that tells ClearCase what configuration of elements you want to work with. You can see that set of rules by issuing the following command:

cleartool  catcs

How do I change my config-spec?

You can edit your config-spec by issuing the following command:

cleartool edcs

Your favorite editor , as specified by the environment variable WINEDITOR (first choice), VISUAL (second choice), or EDITOR (third choice) will be invoked for the editing operation. If none of these environment variables is set then vi will be invoked for the editing operation on UNIX systems and Notepad will be invoked for the editing operation on Windows systems.

About files/directories


What is checked-out and to whom?

If you want to see who has what checked-out, you can use the cleartool lsco command. This command has a number of possible arguments to use depending on the specific information you want. Here are some common ones:

cleartool lsco
Lists all checkouts of elements in the current directory.
cleartool lsco anelement
List checkout information about the element anelement.
cleartool lsco -recurse
Lists all checkouts of elements in the current directory and below.
cleartool lsco -cview
Lists checkouts of elements in the current directory that are checked-out to the current view.
cleartool lsco -cview -recurse
Lists checkouts of elements in the current directory and below that are checked-out to the current view.
cleartool lsco -me
Lists checkouts of elements in the current directory that the current user has checked-out.
cleartool lsco -user fred
Lists checkouts of elements in the current directory that the user with login id "fred" has checked-out.

Please refer to the ClearCase Reference Manual for more detailed information about the cleartool lsco command.

What is the change history of this file/directory?

If you want to see the change history associated with a particular element, you can use the cleartool lsh command.

cleartool lsh anelement
Where anelement is the name of an element under ClearCase control

What versions of what files/directories am I looking at?

To see exactly what versions of elements are being projected to you by your view and why, you can use the cleartool ls command.

cleartool ls

What are the differences between this version of a file/directory and a different version?

To view the differences between the versions of an element visible in your view and another version of the element you can use the cleartool diff command.

cleartool diff -g -pred anelement
Graphically presents the differences between the version of anelement selected by your view and it's immediate predecessor version.
cleartool diff -g anelement anelement@@/main/5
Graphically presents the differences between the version of anelement selected by your view and version 5 on the main branch of anelement.

You can also use this command without the -g option to present the difference information to you textually rather than graphically.

See the cleartool diff entry in the ClearCase Reference Manual for more detailed information on these commands.

What does the version tree look like for this file/directory?

To view a graphical representation of the version tree associated with an element you can use the xlsvtree command.

cleartool lsvtree -g anelement

You can view a textual representation of the version tree associated with an element with the cleartool lsvtree command.

cleartool lsvtree anelement

I want more information about this element?

You can get more detailed information about a particular element with the cleartool describe command.

cleartool describe anelement
Lists information about anelement such as the version selected by your view, who created it and when, the comment associated with the version, the element type and the predecessor version.

Resources

Learn

  • To learn more about IBM Rational products, visit the developerWorks Rational zone. You'll find technical documentation, how-to articles, education, downloads, product information, and more.
  • To get your team up to speed on IBM Rational product technology as quickly as possible, take a self-paced, online training course. There are a variety of web-based training modules available.
  • Browse the technology bookstore for books on these and other technical topics.
  • Learn about upcoming events; including webcasts, seminars, trade shows, user group meetings, and the IBM Rational Software Development User Conference.
  • Whitepapers, analyst reports, and datasheets for IBM Rational ClearCase are available here.
  • IBM Rational software has helped thousands of companies worldwide achieve success in their software development efforts. Read about some of them here.

Get products and technologies

  • Find more resources for ClearCase users and administrators in the ClearCase area of the developerWorks Rational zone, including articles and whitepapers, plug-ins, scripts and triggers; and links to training, discussion forums, product documentation and support.

Discuss

  • The ClearCase discussion forum on developerWorks is a great place to post questions and get answers about configuration management and UCM with IBM Rational ClearCase.

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