Function grep_cli::is_readable_stdin

pub fn is_readable_stdin() -> bool

Returns true if and only if stdin is believed to be readable.

When stdin is readable, command line programs may choose to behave differently than when stdin is not readable. For example, command foo might search the current directory for occurrences of foo where as command foo < some-file or cat some-file | command foo might instead only search stdin for occurrences of foo.