# Installing Files in Other Directories: the &Install; Builder

Once a program is built, it is often appropriate to install it in another directory for public use. You use the &Install; method to arrange for a program, or any other file, to be copied into a destination directory:

env = Environment() hello = env.Program('hello.c') env.Install('__ROOT__/usr/bin', hello)
int main() { printf("Hello, world!\n"); }

Note, however, that installing a file is still considered a type of file "build." This is important when you remember that the default behavior of &SCons; is to build files in or below the current directory. If, as in the example above, you are installing files in a directory outside of the top-level &SConstruct; file's directory tree, you must specify that directory (or a higher directory, such as `/`) for it to install anything there:

scons -Q
scons -Q __ROOT__/usr/bin

It can, however, be cumbersome to remember (and type) the specific destination directory in which the program (or other file) should be installed. A call to &Default; can be used to add the directory to the list of default targets, removing the need to type it, but sometimes you don't want to install on every build. This is an area where the &Alias; function comes in handy, allowing you, for example, to create a pseudo-target named `install` that can expand to the specified destination directory:

env = Environment() hello = env.Program('hello.c') env.Install('__ROOT__/usr/bin', hello) env.Alias('install', '__ROOT__/usr/bin')
int main() { printf("Hello, world!\n"); }

This then yields the more natural ability to install the program in its destination as a separate invocation, as follows:

scons -Q
scons -Q install

## Installing Multiple Files in a Directory

You can install multiple files into a directory simply by calling the &Install; function multiple times:

env = Environment() hello = env.Program('hello.c') goodbye = env.Program('goodbye.c') env.Install('__ROOT__/usr/bin', hello) env.Install('__ROOT__/usr/bin', goodbye) env.Alias('install', '__ROOT__/usr/bin')
int main() { printf("Hello, world!\n"); }
int main() { printf("Goodbye, world!\n"); }

Or, more succinctly, listing the multiple input files in a list (just like you can do with any other builder):

env = Environment() hello = env.Program('hello.c') goodbye = env.Program('goodbye.c') env.Install('__ROOT__/usr/bin', [hello, goodbye]) env.Alias('install', '__ROOT__/usr/bin')

Either of these two examples yields:

scons -Q install

## Installing a File Under a Different Name

The &Install; method preserves the name of the file when it is copied into the destination directory. If you need to change the name of the file when you copy it, use the &InstallAs; function:

env = Environment() hello = env.Program('hello.c') env.InstallAs('__ROOT__/usr/bin/hello-new', hello) env.Alias('install', '__ROOT__/usr/bin')
int main() { printf("Hello, world!\n"); }

This installs the `hello` program with the name `hello-new` as follows:

scons -Q install

## Installing Multiple Files Under Different Names

If you have multiple files that all need to be installed with different file names, you can either call the &InstallAs; function multiple times, or as a shorthand, you can supply same-length lists for both the target and source arguments:

env = Environment() hello = env.Program('hello.c') goodbye = env.Program('goodbye.c') env.InstallAs(['__ROOT__/usr/bin/hello-new', '__ROOT__/usr/bin/goodbye-new'], [hello, goodbye]) env.Alias('install', '__ROOT__/usr/bin')
int main() { printf("Hello, world!\n"); }
int main() { printf("Goodbye, world!\n"); }

In this case, the &InstallAs; function loops through both lists simultaneously, and copies each source file into its corresponding target file name:

scons -Q install

## Installing a Shared Library

If a shared library is created with the &cv-link-SHLIBVERSION; variable set, &scons; will create symbolic links as needed based on that variable. To properly install such a library including the symbolic links, use the &InstallVersionedLib; function.

For example, on a Linux system, this instruction:

foo = env.SharedLibrary(target="foo", source="foo.c", SHLIBVERSION="1.2.3")

Will produce a shared library `libfoo.so.1.2.3` and symbolic links `libfoo.so` and `libfoo.so.1` which point to `libfoo.so.1.2.3`. You can use the Node returned by the &SharedLibrary; builder in order to install the library and its symbolic links in one go without having to list them individually:

env.InstallVersionedLib(target="lib", source=foo)

On systems which expect a shared library to be installed both with a name that indicates the version, for run-time resolution, and as a plain name, for link-time resolution, the &InstallVersionedLib; function can be used. Symbolic links appropriate to the type of system will be generated based on symlinks of the source library.