nc looks like it just does nothing without it. it's nice to see things like "No such file" or "Permission denied".
ok? Index: netcat.c =================================================================== RCS file: /cvs/src/usr.bin/nc/netcat.c,v retrieving revision 1.191 diff -u -p -r1.191 netcat.c --- netcat.c 27 Apr 2018 15:17:53 -0000 1.191 +++ netcat.c 26 Oct 2018 04:57:19 -0000 @@ -616,8 +616,10 @@ main(int argc, char *argv[]) if (!zflag) readwrite(s, NULL); close(s); - } else + } else { + warn("%s", host); ret = 1; + } if (uflag) unlink(unix_dg_tmp_socket); @@ -855,8 +857,8 @@ unix_connect(char *path) errno = save_errno; return -1; } - return s; + return s; } /*