exex provides a custom Cmd type that wraps exec.Cmd in a way that it will always capture standard error stream if execution fails with an exec.ExitError.

The standard library exec package contains a very useful API to execute commands, however, the exec.Cmd.Run and exec.Cmd.Output methods behave differently in the case of a failed execution. In particular, exec.Cmd.Run will NOT populate exec.ExitError.Stderr in the case of failure, whereas exec.Cmd.Output will do. While this is explicitly noted in the exec package documentation, it is a source of confusion even for experienced users.

Another issue with the standard library package is that if we use exec.Cmd.Output to only capture the error we will be incurring in unnecessary allocations because it uses a bytes.Buffer for capturing STDOUT, and also STDERR will be truncated. The wrappers defined in this library do not have this peformance penalization nor truncate any output.

In order to avoid importing both this package and os/exec, this package provides aliases for the variables and top-level functions os/exec provides.

See LICENSE, but basically, MIT.