Determining Piped Input in Go

Understanding if a command is piped is crucial in Go applications, especially when processing data from various sources. This article explores how to determine if a command is piped or not, enabling developers to adapt their code accordingly.

Solution

Go provides the os.Stdin.Stat() function to retrieve the file information associated with the standard input. This information includes the file mode, which indicates whether the input is from a terminal or a pipe. The following code snippet demonstrates how to use os.Stdin.Stat() for this purpose:

package main

import (
    "fmt"
    "os"
)

func main() {
    fi, _ := os.Stdin.Stat()

    if (fi.Mode() & os.ModeCharDevice) == 0 {
        fmt.Println("data is from pipe")
    } else {
        fmt.Println("data is from terminal")
    }
}

When the command is piped, fi.Mode() & os.ModeCharDevice evaluates to 0, indicating that the input is not from a character device (such as a terminal). Conversely, a non-zero value signifies that the input is from a character device.

This approach provides a reliable way to distinguish between piped and non-piped inputs, allowing developers to tailor their applications' behavior accordingly.