Fix last commit (had newline before first ==> name <==) and add -f tests.

2 files changed, 20 insertions, 5 deletions

diff --git a/tests/tail.test b/tests/tail.test
index b3d744aa..c1c44c6a 100755
--- a/tests/tail.test
+++ b/tests/tail.test
@@ -59,3 +59,18 @@ testing "-c 12345 -n 3 bigfile" "tail -c 12345 -n 3 bigfile | md5sum" \
   "347bbdcbad8a313f4dc7bd558c5bfcb8  -\n" "" ""
 testing "-n 3 -c 12345 bigfile" "tail -n 3 -c 12345 bigfile | md5sum" \
   "1698825a750288284ec3ba7d8a59f302  -\n" "" ""
+rm bigfile
+
+echo 111 > one
+testing "-f one" \
+  'tail -f one & sleep .25 ; echo two >> one; sleep .25; echo three >> one; sleep .25; kill $! >/dev/null' \
+  "111\ntwo\nthree\n" "" ""
+rm one
+
+echo uno > one
+echo dos > two
+echo tres > three
+testing "-f one two three" \
+  'tail -f one two three & sleep .25 ; echo more >> three ; echo also >> one; sleep .25; kill $! >/dev/null' \
+  "==> one <==\nuno\n\n==> two <==\ndos\n\n==> three <==\ntres\nmore\n\n==> one <==\nalso\n" "" ""
+rm one two three
diff --git a/toys/posix/tail.c b/toys/posix/tail.c
index bf25a149..1204f1c6 100644
--- a/toys/posix/tail.c
+++ b/toys/posix/tail.c
@@ -3,6 +3,8 @@
  * Copyright 2012 Timothy Elliott <tle@holymonkey.com>
  *
  * See http://opengroup.org/onlinepubs/9699919799/utilities/tail.html
+ *
+ * Deviations from posix: -f waits for pipe/fifo on stdin (nonblock?).
 
 USE_TAIL(NEWTOY(tail, "?fc-n-[-cn]", TOYFLAG_USR|TOYFLAG_BIN))
 
@@ -136,7 +138,7 @@ static void do_tail(int fd, char *name)
   int linepop = 1;
 
   if (toys.optflags & FLAG_f) {
-    int f = (TT.file_no++)*2;
+    int f = TT.file_no*2;
     char *s = name;
 
     if (!fd) sprintf(s = toybuf, "/proc/self/fd/%d", fd);
@@ -145,10 +147,8 @@ static void do_tail(int fd, char *name)
       perror_msg("bad -f on '%s'", name);
   }
 
-  if (toys.optc > 1) {
-    if (TT.file_no) xputc('\n');
-    xprintf("==> %s <==\n", name);
-  }
+  if (TT.file_no++) xputc('\n');
+  if (toys.optc > 1) xprintf("==> %s <==\n", name);
 
   // Are we measuring from the end of the file?