The procfs library is organized by packages based on whether the gathered data is coming from
/proc, /sys, or both. Each package contains an `FS` type which represents the path to either /proc, /sys, or both. For example, current cpu statistics are gathered from
`/proc/stat` and are available via the root procfs package. First, the proc filesystem mount
point is initialized, and then the stat information is read.
```go
fs, err := procfs.NewFS("/proc")
stats, err := fs.Stat()
```
Some sub-packages such as `blockdevice`, require access to both the proc and sys filesystems.
```go
fs, err := blockdevice.NewFS("/proc", "/sys")
stats, err := fs.ProcDiskstats()
```
## Building and Testing
The procfs library is normally built as part of another application. However, when making
changes to the library, the `make test` command can be used to run the API test suite.
### Updating Test Fixtures
The procfs library includes a set of test fixtures which include many example files from
the `/proc` and `/sys` filesystems. These fixtures are included as a [ttar](https://github.com/ideaship/ttar) file
which is extracted automatically during testing. To add/update the test fixtures, first
ensure the `fixtures` directory is up to date by removing the existing directory and then
extracting the ttar file using `make fixtures/.unpacked` or just `make test`.
```bash
rm -rf fixtures
make test
```
Next, make the required changes to the extracted files in the `fixtures` directory. When
the changes are complete, run `make update_fixtures` to create a new `fixtures.ttar` file
based on the updated `fixtures` directory. And finally, verify the changes using
