\-r is not an option in some mailx versions.
``` grant@grantbsd:~[20250827-9:43][#290629]> mailx -h mailx: illegal option -- h Usage: mailx [-dEiInv] [-s subject] [-c cc-addr] [-b bcc-addr] [-F] to-addr ... [-sendmail-option ...] mailx [-dEHiInNv] [-F] -f [name] mailx [-dEHiInNv] [-F] [-u user] mailx [-d] -e [-f name] grant@grantbsd:~[20250827-9:43][#292628]> ```
no options for "from" or "reply to"
You can call sendmail options (though I am running postfix, these options are still valid).
I wasn't able to find a flag for REPLYTO, but found if I set an environmental variable, it was honored, and the "Reply-To:" field was present when I received my test email.
``` grant@grantbsd:~[20250827-9:21][#282634]> setenv REPLYTO noreply@companyx.com grant@grantbsd:~[20250827-9:21][#284633]> echo `now` | mail -s "mail test from grantbsd" grant.j@companyx.com -Fnoreply -fnoreply@companyx.com grant@grantbsd:~[20250827-9:21][#286632]> ```
\-F sets the "sender full name", -f sets the "envelope sender address". These options are noted in the sendmail man page.

I found an alternative solution. You can call sendmail options (though I am running postfix, these options are still valid).
``` grant@grantbsd:~[20250827-9:43][#290629]> mailx -h mailx: illegal option -- h Usage: mailx [-dEiInv] [-s subject] [-c cc-addr] [-b bcc-addr] [-F] to-addr ... [-sendmail-option ...] mailx [-dEHiInNv] [-F] -f [name] mailx [-dEHiInNv] [-F] [-u user] mailx [-d] -e [-f name] grant@grantbsd:~[20250827-9:43][#292628]> ```
no options for "from" or "reply to"
I wasn't able to find a flag for REPLYTO, but found if I set an environmental variable, it was honored, and the "Reply-To:" field was present when I received my test email.
``` grant@grantbsd:~[20250827-9:21][#282634]> setenv REPLYTO noreply@companyx.com grant@grantbsd:~[20250827-9:21][#284633]> echo `now` | mail -s "mail test from grantbsd" grant.j@companyx.com -Fnoreply -fnoreply@companyx.com grant@grantbsd:~[20250827-9:21][#286632]> ```
\-F sets the "sender full name", -f sets the "envelope sender address". These options are noted in the sendmail man page.