In the preceding example, the %setup macro simply uncompressed and unpacked the sources.

In this case, the tar file containing the original sources was created so that the top-level directory was included in the tar file. The name of the top-level directory was also identical to that of the tar file, which was in <name>-<version> format.

However, this is not always the case. Quite often, the original sources unpack into a directory whose name is different from the original tar file. Since RPM assumes that the directory will be called <name>-<version>, when the directory is called something else, it's necessary to use %setup's -n option. Here's an example: Assume for a moment that the cdplayer sources, when unpacked, create a top-level directory named cd-player. In this case, our %setup line would look like this:

%setup -n cd-player

and the resulting commands would look like this:

cd /usr/src/redhat/BUILD

rm -rf cd-player

gzip -dc /usr/src/redhat/SOURCES/cdplayer-1.0.tgz | tar -xvvf -

if [ $? -ne 0 ]; then

  exit $?

fi

cd cd-player

cd /usr/src/redhat/BUILD/cd-player

chown -R root.root .

chmod -R a+rX,g-w,o-w .

The results are identical to using %setup with no options, except for the fact that %setup now does a recursive delete on the directory cd-player (instead of cdplayer-1.0) and changes directory into cd-player (instead of cdplayer-1.0).

Note that all subsequent build-time scripts will change directory into the directory specified by the -n option. This makes -n unsuitable as a means of unpacking sources in directories other than the top-level build directory. In the following sections, we'll show a way around this restriction.

A quick word of warning: If the name specified with the -n option doesn't match the name of the directory created when the sources are unpacked, the build will stop pretty quickly, so it pays to be careful when using this option.

How many times have you grabbed a tar file and unpacked it, only to find that it splattered files all over your current directory? Sometimes source archives are created without a top-level directory.

As you can see from the examples so far, %setup expects the archive to create its own top-level directory. If this isn't the case, you'll need to use the -c option.

This option simply creates the directory and changes directory into it before unpacking the sources. Here's what it looks like:

cd /usr/src/redhat/BUILD

rm -rf cdplayer-1.0

mkdir -p cdplayer-1.0

cd cdplayer-1.0

gzip -dc /usr/src/redhat/SOURCES/cdplayer-1.0.tgz | tar -xvvf -

if [ $? -ne 0 ]; then

  exit $?

fi

cd /usr/src/redhat/BUILD/cdplayer-1.0

chown -R root.root .

chmod -R a+rX,g-w,o-w .

The only changes from using %setup with no options are the mkdir and cd commands, prior to the commands that unpack the sources. Note that you can use the -n option along with -c, so something like %setup -c -n blather works as expected.

The -D option keeps the %setup macro from deleting the software's top-level directory. This option is handy when the sources being unpacked are to be added to an already-existing directory tree. This would be the case when more than one %setup macro is used. Here's what %setup does when the -D option is employed:

cd /usr/src/redhat/BUILD

gzip -dc /usr/src/redhat/SOURCES/cdplayer-1.0.tgz | tar -xvvf -

if [ $? -ne 0 ]; then

  exit $?

fi

cd cdplayer-1.0

cd /usr/src/redhat/BUILD/cdplayer-1.0

chown -R root.root .

chmod -R a+rX,g-w,o-w .

As advertised, the rm prior to the tar command is gone.

The -T option disables %setup's normal unpacking of the archive file specified on the source0 line. Here's what the resulting commands look like:

cd /usr/src/redhat/BUILD

rm -rf cdplayer-1.0

cd cdplayer-1.0

cd /usr/src/redhat/BUILD/cdplayer-1.0

chown -R root.root .

chmod -R a+rX,g-w,o-w .

Doesn't make much sense, does it? There's a method to this madness. We'll see the -T in action in the next section.

The -b option is used in conjunction with the source tag. Specifically, it is used to identify which of the numbered source tags in the spec file are to be unpacked.

The -b option requires a numeric argument matching an existing source tag. If a numeric argument is not provided, the build will fail:

# rpm -ba cdplayer-1.0.spec

Package: cdplayer

Need arg to %setup -b

Build failed.

#

Remembering that the first source tag is implicitly numbered 0, let's see what happens when the %setup line is changed to %setup -b 0:

cd /usr/src/redhat/BUILD

rm -rf cdplayer-1.0

gzip -dc /usr/src/redhat/SOURCES/cdplayer-1.0.tgz | tar -xvvf -

if [ $? -ne 0 ]; then

  exit $?

fi

gzip -dc /usr/src/redhat/SOURCES/cdplayer-1.0.tgz | tar -xvvf -

if [ $? -ne 0 ]; then

exit $?

fi

cd cdplayer-1.0

cd /usr/src/redhat/BUILD/cdplayer-1.0

chown -R root.root .

chmod -R a+rX,g-w,o-w .

That's strange. The sources were unpacked twice. It doesn't make sense until you realize that this is why there is a -T option. Since -T disables the default source file unpacking, and -b selects a particular source file to be unpacked, the two are meant to go together, like this:

%setup -T -b 0

Looking at the resulting commands, we find this:

cd /usr/src/redhat/BUILD

rm -rf cdplayer-1.0

gzip -dc /usr/src/redhat/SOURCES/cdplayer-1.0.tgz | tar -xvvf -

if [ $? -ne 0 ]; then

  exit $?

fi

cd cdplayer-1.0

cd /usr/src/redhat/BUILD/cdplayer-1.0

chown -R root.root .

chmod -R a+rX,g-w,o-w .

That's more like it! Let's go on to the next option.