Re: [PATCH] tail: flush initial output before possibly blocking

[Pádraig Brady]

Jim Meyering wrote:
> I noticed that tail -f "didn't work" when run via ssh.
> I.e., it printed nothing, when I expected it to print the
> last 10 lines.

well spotted.

I was wondering about the loop in the test though.
Can the `kill -0` ever fail. Even if that's not redundant
I'm not sure the file is guaranteed to be written at this stage?
How about:

diff --git a/tests/tail-2/flush-initial b/tests/tail-2/flush-initial
index 2deff84..378440c 100755
--- a/tests/tail-2/flush-initial
+++ b/tests/tail-2/flush-initial
@@ -28,10 +28,11 @@ echo line > in || fail=1
 stdbuf --output=1K tail -f in > out &
 tail_pid=$!

-# Wait for the backgrounded `tail' to start.
-while :; do
-  env kill -0 $tail_pid && break
-  sleep .1
+# wait for a second for the file to be flushed
+count=0
+until test -s out -o $count = 10; do
+    count=$((count+1))
+    sleep .1
 done

 test -s out || fail=1

cheers,
Pádraig.