AnyError returns an `ErrorMatcher` that returns true for an error that matches any of the `ems`.

Command returns a pipeline `Stage` based on the specified external `command`, run with the given command-line `args`.

Command returns a pipeline `Stage` with the name `name`, based on the specified `cmd`.

Function returns a pipeline `Stage` that will run a `StageFunc` in a separate goroutine to process the data.

IgnoreError creates a stage that acts like `s` except that it ignores any errors that are matched by `em`.

IsError returns an ErrorIdentifier for the specified target error, matched using `errors.Is()`.

IsSIGPIPE returns an `ErrorMatcher` that matches `*exec.ExitError`s that were caused by the specified signal.

LinewiseFunction returns a function-based `Stage`.

NewPipeline returns a Pipeline struct with all of the `options` applied.

ScanLFTerminatedLines is a `bufio.SplitFunc` that splits its input into lines at LF characters (not treating CR specially).

ScannerFunction creates a function-based `Stage`.

WithDir sets the default directory for running external commands.

WithStdin assigns stdin to the first command in the pipeline.

WithStdout assigns stdout to the last command in the pipeline.

WithStdoutCloser assigns stdout to the last command in the pipeline, and closes stdout when it's done.

FinishEarly is an error that can be returned by a `Stage` to request that the iteration be ended early (possibly without reading all of its input).

IsEPIPE is an `ErrorMatcher` that matches `syscall.EPIPE` using `errors.Is()`.

IsErrClosedPipe is an `ErrorMatcher` that matches `io.ErrClosedPipe` using `errors.Is()`.

IsPipeError is an `ErrorMatcher` that matches a few different errors that typically result if a stage writes to a subsequent stage that has stopped reading from its stdin.

IsSIGPIPE is an `ErrorMatcher` that matches `*exec.ExitError`s that were caused by SIGPIPE.

Env represents the environment that a pipeline stage should run in.

Pipeline represents a Unix-like pipe that can include multiple stages, including external processes but also and stages written in Go.

Scanner defines the interface (which is implemented by `bufio.Scanner`) that is needed by `AddScannerFunction()`.

Stage is an element of a `Pipeline`.

ErrorFilter is a function that can filter errors from `Stage.Wait()`.

ErrorMatcher decides whether its argument matches some class of errors (e.g., errors that we want to ignore).

LinewiseStageFunc is a function that can be embedded in a `goStage`.

NewScannerFunc is used to create a `Scanner` for scanning input that is coming from `r`.

Option is a type alias for Pipeline functional options.

StageFunc is a function that can be used to power a `goStage`.