Strangely the tail of unixes has diverted. OSX tail does not have
support for "--" or long args. But the same functionality is hidden
under short args.

`--follow=name`, `--lines=` and `--retry` is not supported by OSX tail.

- `--lines=` is replaced by the short alternative `-n`

>      -n, --lines=[+]NUM
>             output the last NUM lines, instead of the last 10; or use
>             -n +NUM to output starting with line NUM
>
> tail(1) — Linux manual page

- `--follow=name` and `--retry` by `-F`

>      -F     same as --follow=name --retry
>
> tail(1) — Linux manual page

There is some trade off regarding descriptiveness but OSX support
seams preferable - OSX user

Tested on linux as well so I don't belive this will break on linux.
---
 detached.el           | 8 ++++----
 test/detached-test.el | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/detached.el b/detached.el
index b878ea6..73c3eee 100644
--- a/detached.el
+++ b/detached.el
@@ -919,8 +919,8 @@ Optionally CONCAT the command return command into a string."
 Optionally CONCAT the command return command into a string."
   (detached-connection-local-variables
    (let* ((log (detached--session-file session 'log t))
-          (tail-command `(,detached-tail-program "--follow=name" "--retry"
-                                                 ,(concat "--lines="
detached-session-context-lines)
+          (tail-command `(,detached-tail-program "-F"
+                                                 ,(concat "-n "
detached-session-context-lines)
                                                  ,log)))
      (cond ((eq 'create detached-session-mode)
             (detached--dtach-command session))
@@ -957,7 +957,7 @@ Optionally CONCAT the command return command into a string."
          (if concat
              (string-join
               `(,(when detached-show-session-context
-                   (format  "%s --lines=%s %s;" detached-tail-program
detached-session-context-lines log))
+                   (format  "%s -n %s %s;" detached-tail-program
detached-session-context-lines log))
                 ,detached-dtach-program
                 ,dtach-arg
                 ,socket
@@ -965,7 +965,7 @@ Optionally CONCAT the command return command into a string."
               " ")
            (append
             (when detached-show-session-context
-              `(,detached-tail-program ,(format "--lines=%s"
detached-session-context-lines)
+              `(,detached-tail-program ,(format "-n %s"
detached-session-context-lines)
                                        ,(concat log ";")))
             `(,detached-dtach-program ,dtach-arg ,socket "-r" "none")))
        (if concat
diff --git a/test/detached-test.el b/test/detached-test.el
index 513eb72..b53c02c 100644
--- a/test/detached-test.el
+++ b/test/detached-test.el
@@ -96,11 +96,11 @@
      (let* ((detached-session-mode 'attach)
             (log (detached--session-file session 'log t))
             (expected `(,detached-tail-program
-                        ,(format "--lines=%s" detached-session-context-lines)
+                        ,(format "-n %s" detached-session-context-lines)
                         ,(format "%s;" log)
                         ,detached-dtach-program "-a"
,(detached--session-file session 'socket t) "-r" "none"))
             (expected-concat (format "%s %s; %s -a %s -r none"
-                                     (format "%s --lines=%s"
detached-tail-program detached-session-context-lines)
+                                     (format "%s -n %s"
detached-tail-program detached-session-context-lines)
                                      log
                                      detached-dtach-program
                                      (detached--session-file session
'socket t))))
-- 
2.30.1 (Apple Git-130)