While working with this I noticed that setting content from stdin only works with pipes/FIFOs. Redirecting a files content to stdin using shell redirection command < file is not treated as "having data in stdin".
Is there any particular reason for this check? It is in https://github.com/ankitpokhrel/jira-cli/blame/eb842e18014303a575fde8e19508b3c7c13982c5/internal/cmdutil/utils.go#L135

if fi.Mode()&os.ModeNamedPipe == 0 {
		return false
	}

With this removed, both of these work:

jira issue edit IN-4 --no-input < upgrade-clusters.md 
cat upgrade-clusters.md | jira issue edit IN-4 --no-input 

Hi @erpel, apologies for the late response.

I don't exactly remember the reason behind this check, TBH. Perhaps it was overlooked when working on the initial feature. I think we can update the method StdinHasData to something like the one below, so that it considers both stdin and file redirection.

import "golang.org/x/crypto/ssh/terminal"

func StdinHasData() bool {
	if terminal.IsTerminal(int(os.Stdin.Fd())) {
		return false
	}
	return true
}

Thanks for looking into this.
I took a look at "golang.org/x/crypto/ssh/terminal" and its IsTerminal function. Since it's just a wrapper around functionality in "golang.org/x/term" which was an indirect dependency already I opted to use this instead. Let me know what you think.