What is a build tool?

Question

For past 4 years, I have been programming with Eclipse (for Java), and Visual Studio Express (for C#). The IDEs mentioned always seemed to provide every facility a programmer might ask for (related to programming, of course).

Lately I have been hearing about something called "build tools". I heard they're used almost in all kind of real world development. What are they exactly? What problems are they designed to solve? How come I never needed them in past four years? Are they kind of command-line stripped down IDEs?

Answer 1

These are different types of processes by which you can get your builds done.

1. Continuous Integration build: In this mainly developers check-in their code and right after their check-in a build initiates for building of the recent changes so we should know whether the changes done by the developer has worked or not right after the check-in is done. This is preferred for smaller projects or components of the projects. In case where multiple teams are associated with the project or there are a large no. of developers working on the same project this scenario becomes difficult to handle as if there are 'n' no. of check-in’s and the build fails at certain points it becomes highly difficult to trace whether all the breakage has occurred because of one issue or with multiple issues so if the older issues are not addressed properly than it becomes very difficult to trace down the later defects that occurred after that change. The main benefit of these builds is that we get to know whether a particular check-in is successful or not.

2. Gated check-in builds: In this type of check in a build is initiated right after the check in is done keeping the changes in a shelve sets. In this case if the build succeeds than the shelve-set check-in gets committed otherwise it will not be committed to the Team Foundation Server. This gives a slightly better picture from the continuous integration build as only the successful check-in's are allowed to get committed.

3. Nightly builds: This is also referred as Scheduled builds. In this case we schedule the builds to run for a specific time in order to build the changes. All the previous uncommitted changes from the last build are built during this build process. This is practiced when we want to check in multiple times but do not want a build every time we check in our code so we can have a fixed time or period in which we can initiate the build for building of the checked-in code.

The more details about these builds can be found at the below location.

Gated-check in Builds

Continuous Integration Builds

Nightly Builds

Answer 2

You have been using them - IDE is a build tool. For the command line you can use things like make.

People use command line tools for things like a nightly build - so in the morning with a hangover the programmer has realised that the code that he has been fiddling with with the latest builds of the libraries does not work!