Showing Information of Packages

You can get detailed information of a package using the spack info command:

spack info <package_name>

For example, to show the detailed information of the zlib package, type:

spack info zlib

Output:

Package:   zlib

Description:
    A free, general-purpose, legally unencumbered lossless data-compression
    library.

Homepage: http://zlib.net

Tags:
    None

Preferred version:
    1.2.11    http://zlib.net/fossils/zlib-1.2.11.tar.gz

Safe versions:
    1.2.11    http://zlib.net/fossils/zlib-1.2.11.tar.gz
    1.2.8     http://zlib.net/fossils/zlib-1.2.8.tar.gz
    1.2.3     http://zlib.net/fossils/zlib-1.2.3.tar.gz

Variants:
    Name [Default]    Allowed values    Description
    ==============    ==============    ================================================

    optimize [on]     on, off           Enable -O2 for a more optimized lib
    pic [on]          on, off           Produce position-independent code (for shared
                                        libs)
    shared [on]       on, off           Enables the build of shared libraries.

Installation Phases:
    install

Build Dependencies:
    None

Link Dependencies:
    None

Run Dependencies:
    None

Virtual Packages:
    None

From the above output, you can have a general idea about the package by looking at the description part. Also, the package information lists the available versions of the package; 1.2.11 which is the default version, 1.2.8, and 1.2.3. Furthermore, the output shows the variants and their value types. For example, optimize is boolean and its default value is always ON. The output shows that there are no dependencies of the zlib package.