Merge remote-tracking branch 'toybox/master' into HEAD

Change-Id: I69a04951b0d27c7c3fa05ef51278fb2087851488
diff --git a/android/device/generated/flags.h b/android/device/generated/flags.h
index de3425d..fb87274 100644
--- a/android/device/generated/flags.h
+++ b/android/device/generated/flags.h
@@ -2948,9 +2948,9 @@
 #undef FOR_tac
 #endif
 
-// tail ?fFs#=1c-n-[-cn][-fF] ?fFs#=1c-n-[-cn][-fF]
+// tail ?fFs:c-n-[-cn][-fF] ?fFs:c-n-[-cn][-fF]
 #undef OPTSTR_tail
-#define OPTSTR_tail "?fFs#=1c-n-[-cn][-fF]"
+#define OPTSTR_tail "?fFs:c-n-[-cn][-fF]"
 #ifdef CLEANUP_tail
 #undef CLEANUP_tail
 #undef FOR_tail
diff --git a/android/device/generated/globals.h b/android/device/generated/globals.h
index 73cc23c..6eae6f7 100644
--- a/android/device/generated/globals.h
+++ b/android/device/generated/globals.h
@@ -1472,10 +1472,17 @@
 // toys/posix/tail.c
 
 struct tail_data {
-  long n, c, s;
-  int file_no, last_fd;
+  long n, c;
+  char *s;
+
+  int file_no, last_fd, ss;
   struct xnotify *not;
-  struct follow_file *F;
+  struct {
+    char *path;
+    int fd;
+    dev_t dev;
+    ino_t ino;
+  } *F;
 };
 
 // toys/posix/tar.c
diff --git a/android/device/generated/help.h b/android/device/generated/help.h
index e1e10a6..465475e 100644
--- a/android/device/generated/help.h
+++ b/android/device/generated/help.h
@@ -512,7 +512,7 @@
 
 #define HELP_strings "usage: strings [-fo] [-t oxd] [-n LEN] [FILE...]\n\nDisplay printable strings in a binary file\n\n-f	Show filename\n-n	At least LEN characters form a string (default 4)\n-o	Show offset (ala -t d)\n-t	Show offset type (o=octal, d=decimal, x=hexadecimal)"
 
-#define HELP_split "usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [-n PARTS] [INPUT [OUTPUT]]\n\nCopy INPUT (or stdin) data to a series of OUTPUT (or \"x\") files with\nalphabetically increasing suffix (aa, ab, ac... az, ba, bb...).\n\n-a	Suffix length (default 2)\n-b	BYTES/file (10, 10k, 10m, 10g...)\n-l	LINES/file (default 1000)\n-n	PARTS"
+#define HELP_split "usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [-n PARTS] [INPUT [OUTPUT]]\n\nCopy INPUT (or stdin) data to a series of OUTPUT (or \"x\") files with\nalphabetically increasing suffix (aa, ab, ac... az, ba, bb...).\n\n-a	Suffix length (default 2)\n-b	BYTES/file (10, 10k, 10m, 10g...)\n-l	LINES/file (default 1000)\n-n	PARTS many equal length files"
 
 #define HELP_sort "usage: sort [-Mbcdfginrsuz] [FILE...] [-k#[,#[x]] [-t X]] [-o FILE]\n\nSort all lines of text from input files (or stdin) to stdout.\n-M	Month sort (jan, feb, etc)\n-V	Version numbers (name-1.234-rc6.5b.tgz)\n-b	Ignore leading blanks (or trailing blanks in second part of key)\n-c	Check whether input is sorted\n-d	Dictionary order (use alphanumeric and whitespace chars only)\n-f	Force uppercase (case insensitive sort)\n-g	General numeric sort (double precision with nan and inf)\n-i	Ignore nonprinting characters\n-k	Sort by \"key\" (see below)\n-n	Numeric order (instead of alphabetical)\n-o	Output to FILE instead of stdout\n-r	Reverse\n-s	Skip fallback sort (only sort with keys)\n-t	Use a key separator other than whitespace\n-u	Unique lines only\n-x	Hexadecimal numerical sort\n-z	Zero (null) terminated lines\n\nSorting by key looks at a subset of the words on each line. -k2 uses the\nsecond word to the end of the line, -k2,2 looks at only the second word,\n-k2,4 looks from the start of the second to the end of the fourth word.\n-k2.4,5 starts from the fourth character of the second word, to the end\nof the fifth word. Specifying multiple keys uses the later keys as tie\nbreakers, in order. A type specifier appended to a sort key (such as -2,2n)\napplies only to sorting that key."
 
diff --git a/android/device/generated/newtoys.h b/android/device/generated/newtoys.h
index ad171c5..a37ec0c 100644
--- a/android/device/generated/newtoys.h
+++ b/android/device/generated/newtoys.h
@@ -263,7 +263,7 @@
 USE_SYSCTL(NEWTOY(sysctl, "^neNqwpaA[!ap][!aq][!aw][+aA]", TOYFLAG_SBIN))
 USE_SYSLOGD(NEWTOY(syslogd,">0l#<1>8=8R:b#<0>99=1s#<0=200m#<0>71582787=20O:p:f:a:nSKLD", TOYFLAG_SBIN|TOYFLAG_STAYROOT))
 USE_TAC(NEWTOY(tac, NULL, TOYFLAG_USR|TOYFLAG_BIN))
-USE_TAIL(NEWTOY(tail, "?fFs#=1c-n-[-cn][-fF]", TOYFLAG_USR|TOYFLAG_BIN))
+USE_TAIL(NEWTOY(tail, "?fFs:c-n-[-cn][-fF]", TOYFLAG_USR|TOYFLAG_BIN))
 USE_TAR(NEWTOY(tar, "&(restrict)(full-time)(no-recursion)(numeric-owner)(no-same-permissions)(overwrite)(exclude)*(mode):(mtime):(group):(owner):(to-command):o(no-same-owner)p(same-permissions)k(keep-old)c(create)|h(dereference)x(extract)|t(list)|v(verbose)I(use-compress-program):J(xz)j(bzip2)z(gzip)S(sparse)O(to-stdout)P(absolute-names)m(touch)X(exclude-from)*T(files-from)*C(directory):f(file):a[!txc][!jzJa]", TOYFLAG_USR|TOYFLAG_BIN))
 USE_TASKSET(NEWTOY(taskset, "<1^pa", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT))
 USE_TCPSVD(NEWTOY(tcpsvd, "^<3c#=30<1C:b#=20<0u:l:hEv", TOYFLAG_USR|TOYFLAG_BIN))
diff --git a/android/linux/generated/flags.h b/android/linux/generated/flags.h
index 15e3f81..8ccf8f0 100644
--- a/android/linux/generated/flags.h
+++ b/android/linux/generated/flags.h
@@ -2948,9 +2948,9 @@
 #undef FOR_tac
 #endif
 
-// tail ?fFs#=1c-n-[-cn][-fF] ?fFs#=1c-n-[-cn][-fF]
+// tail ?fFs:c-n-[-cn][-fF] ?fFs:c-n-[-cn][-fF]
 #undef OPTSTR_tail
-#define OPTSTR_tail "?fFs#=1c-n-[-cn][-fF]"
+#define OPTSTR_tail "?fFs:c-n-[-cn][-fF]"
 #ifdef CLEANUP_tail
 #undef CLEANUP_tail
 #undef FOR_tail
diff --git a/android/linux/generated/globals.h b/android/linux/generated/globals.h
index 73cc23c..6eae6f7 100644
--- a/android/linux/generated/globals.h
+++ b/android/linux/generated/globals.h
@@ -1472,10 +1472,17 @@
 // toys/posix/tail.c
 
 struct tail_data {
-  long n, c, s;
-  int file_no, last_fd;
+  long n, c;
+  char *s;
+
+  int file_no, last_fd, ss;
   struct xnotify *not;
-  struct follow_file *F;
+  struct {
+    char *path;
+    int fd;
+    dev_t dev;
+    ino_t ino;
+  } *F;
 };
 
 // toys/posix/tar.c
diff --git a/android/linux/generated/help.h b/android/linux/generated/help.h
index 161d57d..7b121e2 100644
--- a/android/linux/generated/help.h
+++ b/android/linux/generated/help.h
@@ -514,7 +514,7 @@
 
 #define HELP_strings "usage: strings [-fo] [-t oxd] [-n LEN] [FILE...]\n\nDisplay printable strings in a binary file\n\n-f	Show filename\n-n	At least LEN characters form a string (default 4)\n-o	Show offset (ala -t d)\n-t	Show offset type (o=octal, d=decimal, x=hexadecimal)"
 
-#define HELP_split "usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [-n PARTS] [INPUT [OUTPUT]]\n\nCopy INPUT (or stdin) data to a series of OUTPUT (or \"x\") files with\nalphabetically increasing suffix (aa, ab, ac... az, ba, bb...).\n\n-a	Suffix length (default 2)\n-b	BYTES/file (10, 10k, 10m, 10g...)\n-l	LINES/file (default 1000)\n-n	PARTS"
+#define HELP_split "usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [-n PARTS] [INPUT [OUTPUT]]\n\nCopy INPUT (or stdin) data to a series of OUTPUT (or \"x\") files with\nalphabetically increasing suffix (aa, ab, ac... az, ba, bb...).\n\n-a	Suffix length (default 2)\n-b	BYTES/file (10, 10k, 10m, 10g...)\n-l	LINES/file (default 1000)\n-n	PARTS many equal length files"
 
 #define HELP_sort "usage: sort [-Mbcdfginrsuz] [FILE...] [-k#[,#[x]] [-t X]] [-o FILE]\n\nSort all lines of text from input files (or stdin) to stdout.\n-M	Month sort (jan, feb, etc)\n-V	Version numbers (name-1.234-rc6.5b.tgz)\n-b	Ignore leading blanks (or trailing blanks in second part of key)\n-c	Check whether input is sorted\n-d	Dictionary order (use alphanumeric and whitespace chars only)\n-f	Force uppercase (case insensitive sort)\n-g	General numeric sort (double precision with nan and inf)\n-i	Ignore nonprinting characters\n-k	Sort by \"key\" (see below)\n-n	Numeric order (instead of alphabetical)\n-o	Output to FILE instead of stdout\n-r	Reverse\n-s	Skip fallback sort (only sort with keys)\n-t	Use a key separator other than whitespace\n-u	Unique lines only\n-x	Hexadecimal numerical sort\n-z	Zero (null) terminated lines\n\nSorting by key looks at a subset of the words on each line. -k2 uses the\nsecond word to the end of the line, -k2,2 looks at only the second word,\n-k2,4 looks from the start of the second to the end of the fourth word.\n-k2.4,5 starts from the fourth character of the second word, to the end\nof the fifth word. Specifying multiple keys uses the later keys as tie\nbreakers, in order. A type specifier appended to a sort key (such as -2,2n)\napplies only to sorting that key."
 
diff --git a/android/linux/generated/newtoys.h b/android/linux/generated/newtoys.h
index ad171c5..a37ec0c 100644
--- a/android/linux/generated/newtoys.h
+++ b/android/linux/generated/newtoys.h
@@ -263,7 +263,7 @@
 USE_SYSCTL(NEWTOY(sysctl, "^neNqwpaA[!ap][!aq][!aw][+aA]", TOYFLAG_SBIN))
 USE_SYSLOGD(NEWTOY(syslogd,">0l#<1>8=8R:b#<0>99=1s#<0=200m#<0>71582787=20O:p:f:a:nSKLD", TOYFLAG_SBIN|TOYFLAG_STAYROOT))
 USE_TAC(NEWTOY(tac, NULL, TOYFLAG_USR|TOYFLAG_BIN))
-USE_TAIL(NEWTOY(tail, "?fFs#=1c-n-[-cn][-fF]", TOYFLAG_USR|TOYFLAG_BIN))
+USE_TAIL(NEWTOY(tail, "?fFs:c-n-[-cn][-fF]", TOYFLAG_USR|TOYFLAG_BIN))
 USE_TAR(NEWTOY(tar, "&(restrict)(full-time)(no-recursion)(numeric-owner)(no-same-permissions)(overwrite)(exclude)*(mode):(mtime):(group):(owner):(to-command):o(no-same-owner)p(same-permissions)k(keep-old)c(create)|h(dereference)x(extract)|t(list)|v(verbose)I(use-compress-program):J(xz)j(bzip2)z(gzip)S(sparse)O(to-stdout)P(absolute-names)m(touch)X(exclude-from)*T(files-from)*C(directory):f(file):a[!txc][!jzJa]", TOYFLAG_USR|TOYFLAG_BIN))
 USE_TASKSET(NEWTOY(taskset, "<1^pa", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT))
 USE_TCPSVD(NEWTOY(tcpsvd, "^<3c#=30<1C:b#=20<0u:l:hEv", TOYFLAG_USR|TOYFLAG_BIN))
diff --git a/android/mac/generated/flags.h b/android/mac/generated/flags.h
index d015b67..f032f90 100644
--- a/android/mac/generated/flags.h
+++ b/android/mac/generated/flags.h
@@ -2948,9 +2948,9 @@
 #undef FOR_tac
 #endif
 
-// tail ?fFs#=1c-n-[-cn][-fF] ?fFs#=1c-n-[-cn][-fF]
+// tail ?fFs:c-n-[-cn][-fF] ?fFs:c-n-[-cn][-fF]
 #undef OPTSTR_tail
-#define OPTSTR_tail "?fFs#=1c-n-[-cn][-fF]"
+#define OPTSTR_tail "?fFs:c-n-[-cn][-fF]"
 #ifdef CLEANUP_tail
 #undef CLEANUP_tail
 #undef FOR_tail
diff --git a/android/mac/generated/globals.h b/android/mac/generated/globals.h
index 73cc23c..6eae6f7 100644
--- a/android/mac/generated/globals.h
+++ b/android/mac/generated/globals.h
@@ -1472,10 +1472,17 @@
 // toys/posix/tail.c
 
 struct tail_data {
-  long n, c, s;
-  int file_no, last_fd;
+  long n, c;
+  char *s;
+
+  int file_no, last_fd, ss;
   struct xnotify *not;
-  struct follow_file *F;
+  struct {
+    char *path;
+    int fd;
+    dev_t dev;
+    ino_t ino;
+  } *F;
 };
 
 // toys/posix/tar.c
diff --git a/android/mac/generated/help.h b/android/mac/generated/help.h
index 161d57d..7b121e2 100644
--- a/android/mac/generated/help.h
+++ b/android/mac/generated/help.h
@@ -514,7 +514,7 @@
 
 #define HELP_strings "usage: strings [-fo] [-t oxd] [-n LEN] [FILE...]\n\nDisplay printable strings in a binary file\n\n-f	Show filename\n-n	At least LEN characters form a string (default 4)\n-o	Show offset (ala -t d)\n-t	Show offset type (o=octal, d=decimal, x=hexadecimal)"
 
-#define HELP_split "usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [-n PARTS] [INPUT [OUTPUT]]\n\nCopy INPUT (or stdin) data to a series of OUTPUT (or \"x\") files with\nalphabetically increasing suffix (aa, ab, ac... az, ba, bb...).\n\n-a	Suffix length (default 2)\n-b	BYTES/file (10, 10k, 10m, 10g...)\n-l	LINES/file (default 1000)\n-n	PARTS"
+#define HELP_split "usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [-n PARTS] [INPUT [OUTPUT]]\n\nCopy INPUT (or stdin) data to a series of OUTPUT (or \"x\") files with\nalphabetically increasing suffix (aa, ab, ac... az, ba, bb...).\n\n-a	Suffix length (default 2)\n-b	BYTES/file (10, 10k, 10m, 10g...)\n-l	LINES/file (default 1000)\n-n	PARTS many equal length files"
 
 #define HELP_sort "usage: sort [-Mbcdfginrsuz] [FILE...] [-k#[,#[x]] [-t X]] [-o FILE]\n\nSort all lines of text from input files (or stdin) to stdout.\n-M	Month sort (jan, feb, etc)\n-V	Version numbers (name-1.234-rc6.5b.tgz)\n-b	Ignore leading blanks (or trailing blanks in second part of key)\n-c	Check whether input is sorted\n-d	Dictionary order (use alphanumeric and whitespace chars only)\n-f	Force uppercase (case insensitive sort)\n-g	General numeric sort (double precision with nan and inf)\n-i	Ignore nonprinting characters\n-k	Sort by \"key\" (see below)\n-n	Numeric order (instead of alphabetical)\n-o	Output to FILE instead of stdout\n-r	Reverse\n-s	Skip fallback sort (only sort with keys)\n-t	Use a key separator other than whitespace\n-u	Unique lines only\n-x	Hexadecimal numerical sort\n-z	Zero (null) terminated lines\n\nSorting by key looks at a subset of the words on each line. -k2 uses the\nsecond word to the end of the line, -k2,2 looks at only the second word,\n-k2,4 looks from the start of the second to the end of the fourth word.\n-k2.4,5 starts from the fourth character of the second word, to the end\nof the fifth word. Specifying multiple keys uses the later keys as tie\nbreakers, in order. A type specifier appended to a sort key (such as -2,2n)\napplies only to sorting that key."
 
diff --git a/android/mac/generated/newtoys.h b/android/mac/generated/newtoys.h
index ad171c5..a37ec0c 100644
--- a/android/mac/generated/newtoys.h
+++ b/android/mac/generated/newtoys.h
@@ -263,7 +263,7 @@
 USE_SYSCTL(NEWTOY(sysctl, "^neNqwpaA[!ap][!aq][!aw][+aA]", TOYFLAG_SBIN))
 USE_SYSLOGD(NEWTOY(syslogd,">0l#<1>8=8R:b#<0>99=1s#<0=200m#<0>71582787=20O:p:f:a:nSKLD", TOYFLAG_SBIN|TOYFLAG_STAYROOT))
 USE_TAC(NEWTOY(tac, NULL, TOYFLAG_USR|TOYFLAG_BIN))
-USE_TAIL(NEWTOY(tail, "?fFs#=1c-n-[-cn][-fF]", TOYFLAG_USR|TOYFLAG_BIN))
+USE_TAIL(NEWTOY(tail, "?fFs:c-n-[-cn][-fF]", TOYFLAG_USR|TOYFLAG_BIN))
 USE_TAR(NEWTOY(tar, "&(restrict)(full-time)(no-recursion)(numeric-owner)(no-same-permissions)(overwrite)(exclude)*(mode):(mtime):(group):(owner):(to-command):o(no-same-owner)p(same-permissions)k(keep-old)c(create)|h(dereference)x(extract)|t(list)|v(verbose)I(use-compress-program):J(xz)j(bzip2)z(gzip)S(sparse)O(to-stdout)P(absolute-names)m(touch)X(exclude-from)*T(files-from)*C(directory):f(file):a[!txc][!jzJa]", TOYFLAG_USR|TOYFLAG_BIN))
 USE_TASKSET(NEWTOY(taskset, "<1^pa", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT))
 USE_TCPSVD(NEWTOY(tcpsvd, "^<3c#=30<1C:b#=20<0u:l:hEv", TOYFLAG_USR|TOYFLAG_BIN))
diff --git a/lib/dirtree.c b/lib/dirtree.c
index 43ecbd8..4023101 100644
--- a/lib/dirtree.c
+++ b/lib/dirtree.c
@@ -162,7 +162,6 @@
   // according to the fddir() man page, the filehandle in the DIR * can still
   // be externally used by things that don't lseek() it.
 
-  // The extra parentheses are to shut the stupid compiler up.
   while ((entry = readdir(dir))) {
     if ((flags&DIRTREE_PROC) && !isdigit(*entry->d_name)) continue;
     if (!(new = dirtree_add_node(node, entry->d_name, flags))) continue;
diff --git a/lib/lib.c b/lib/lib.c
index 9f9b813..49fd5dd 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -713,9 +713,9 @@
 void loopfiles_rw(char **argv, int flags, int permissions,
   void (*function)(int fd, char *name))
 {
-  int fd, failok = !(flags&WARN_ONLY);
+  int fd, failok = !(flags&WARN_ONLY), anyway = flags & LOOPFILES_ANYWAY;
 
-  flags &= ~WARN_ONLY;
+  flags &= ~(WARN_ONLY|LOOPFILES_ANYWAY);
 
   // If no arguments, read from stdin.
   if (!*argv) function((flags & O_ACCMODE) != O_RDONLY ? 1 : 0, "-");
@@ -726,10 +726,10 @@
     if (!strcmp(*argv, "-")) fd = 0;
     else if (0>(fd = notstdio(open(*argv, flags, permissions))) && !failok) {
       perror_msg_raw(*argv);
-      continue;
+      if (!anyway) continue;
     }
     function(fd, *argv);
-    if ((flags & O_CLOEXEC) && fd) close(fd);
+    if ((flags & O_CLOEXEC) && fd>0) close(fd);
   } while (*++argv);
 }
 
diff --git a/lib/lib.h b/lib/lib.h
index cf1920f..7484eb8 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -112,7 +112,8 @@
 // Tell xopen and friends to print warnings but return -1 as necessary
 // The largest O_BLAH flag so far is arch/alpha's O_PATH at 0x800000 so
 // plenty of headroom.
-#define WARN_ONLY (1<<31)
+#define WARN_ONLY        (1<<31) // don't exit, just warn
+#define LOOPFILES_ANYWAY (1<<30) // call function with fd -1
 
 // xwrap.c
 void xstrncpy(char *dest, char *src, size_t size);
diff --git a/tests/cp.test b/tests/cp.test
index b0d5d3a..3e25f6c 100755
--- a/tests/cp.test
+++ b/tests/cp.test
@@ -140,6 +140,14 @@
   'two\n' '' ''
 testing '-u2' 'echo two>two; sleep .1; echo one>one; cp -u one two; cat two' \
   'one\n' '' ''
+mkdir a b
+
+echo potato > a/one
+echo potato > a/two
+touch b/one b/two
+testing '-i' 'cp -ri a/. b/. 2>/dev/null; cmp -s a/one b/one || cmp -s a/one b/two && echo yes' \
+  'yes\n' '' 'n\ny\n'
+rm -rf one two a b
 
 # cp -r ../source destdir
 # cp -r one/two/three missing
diff --git a/tests/split.test b/tests/split.test
index 4a52243..57270ff 100755
--- a/tests/split.test
+++ b/tests/split.test
@@ -5,21 +5,21 @@
 #testing "name" "command" "result" "infile" "stdin"
 
 testing "split" "seq 1 12345 | split && ls xa[a-z] | wc -l" "13\n" "" ""
-rm xa[a-z]
+rm -f xa[a-z]
 
 testing "-" "seq 1 12345 | split - && ls xa[a-z] | wc -l" "13\n" "" ""
-rm xa[a-z]
+rm -f xa[a-z]
 
 seq 1 12345 > file
 testing "file" "split file && ls xa[a-z] | wc -l" "13\n" "" ""
-rm xa[a-z]
+rm -f xa[a-z]
 
-testing "-l" "split file -l 10k && wc -l xab" "2105 xab\n" "" ""
-rm xa[ab]
+toyonly testing "-l" "split file -l 10k && wc -l xab" "2105 xab\n" "" ""
+rm -f xa[ab]
 
 testing "suffix exhaustion" \
   "split file -l 10 -a 1 walrus 2>/dev/null || ls walrus* | wc -l" "26\n" "" ""
-rm walrus*
+rm -f walrus*
 
 testing "bytes" \
   "seq 1 20000 | split -b 100 -a 3 - whang && ls whang* | wc -l && wc -c whangbpw" "1089\n94 whangbpw\n" "" ""
@@ -27,5 +27,9 @@
 testing "reassembly" \
   'ls whang* | sort | xargs cat > reassembled && seq 1 20000 | diff -u reassembled - && echo yes' \
   "yes\n" "" ""
+rm -f file whang* reassembled
 
-rm file whang* reassembled
+testing "-n" "split -n 3 input; md5sum xaa xab xac" \
+  "494bb8fb423bfa1a5fd66dd0b98f866d  xaa\n449acfdbc692780de30a2df05c5d32aa  xab\n15ab4be57aebe9a1e445195d5094036c  xac\n" \
+  "$(seq 1 10000)" ""
+
diff --git a/tests/tail.test b/tests/tail.test
index 036f433..94644c8 100755
--- a/tests/tail.test
+++ b/tests/tail.test
@@ -73,3 +73,9 @@
   '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
+
+testing "-F" "tail -s .1 -F walrus 2>/dev/null & sleep .2; echo hello > walrus;
+sleep .2; truncate -s 0 walrus; sleep .2; echo potato >> walrus; sleep .2;
+echo hello >> walrus; sleep .2; rm walrus; sleep .2; echo done > walrus;
+  sleep .5; kill %1" "hello\npotato\nhello\ndone\n" "" ""
+rm -f walrus
diff --git a/toys/posix/cp.c b/toys/posix/cp.c
index 8eaecc9..ed62f04 100644
--- a/toys/posix/cp.c
+++ b/toys/posix/cp.c
@@ -124,9 +124,10 @@
 static int cp_node(struct dirtree *try)
 {
   int fdout = -1, cfd = try->parent ? try->parent->extra : AT_FDCWD,
+      save = DIRTREE_SAVE*(CFG_MV && toys.which->name[0] == 'm'), rc = 0,
       tfd = dirtree_parentfd(try);
   unsigned flags = toys.optflags;
-  char *catch = try->parent ? try->name : TT.destname, *err = "%s";
+  char *s = 0, *catch = try->parent ? try->name : TT.destname, *err = "%s";
   struct stat cst;
 
   if (!dirtree_notdotdot(try)) return 0;
@@ -135,8 +136,13 @@
   if (S_ISDIR(try->st.st_mode) && try->again) {
     fdout = try->extra;
     err = 0;
-  } else {
 
+    // If mv child had a problem, free data and don't try to delete parent dir.
+    if (try->child) {
+      save = 0;
+      llist_traverse(try->child, free);
+    }
+  } else {
     // -d is only the same as -r for symlinks, not for directories
     if (S_ISLNK(try->st.st_mode) && (flags & FLAG_d)) flags |= FLAG_r;
 
@@ -150,35 +156,27 @@
       error_msg("'%s' is '%s'", catch, err = dirtree_path(try, 0));
       free(err);
 
-      return 0;
+      return save;
     }
 
     // Handle -inuvF
-
     if (!faccessat(cfd, catch, F_OK, 0) && !S_ISDIR(cst.st_mode)) {
-      char *s;
-
-      if (S_ISDIR(try->st.st_mode)) {
+      if (S_ISDIR(try->st.st_mode))
         error_msg("dir at '%s'", s = dirtree_path(try, 0));
-        free(s);
-        return 0;
-      } else if ((flags & FLAG_F) && unlinkat(cfd, catch, 0)) {
+      else if ((flags & FLAG_F) && unlinkat(cfd, catch, 0))
         error_msg("unlink '%s'", catch);
-        return 0;
-      } else if (flags & FLAG_n) return 0;
-      else if ((flags & FLAG_u) && nanodiff(&try->st.st_mtim, &cst.st_mtim)>0)
-        return 0;
       else if (flags & FLAG_i) {
         fprintf(stderr, "%s: overwrite '%s'", toys.which->name,
           s = dirtree_path(try, 0));
-        free(s);
-        if (!yesno(0)) return 0;
-      }
+        if (yesno(0)) rc++;
+      } else if (!((flags&FLAG_u) && nanodiff(&try->st.st_mtim, &cst.st_mtim)>0)
+                 && !(flags & FLAG_n)) rc++;
+      free(s);
+      if (!rc) return save;
     }
 
     if (flags & FLAG_v) {
-      char *s = dirtree_path(try, 0);
-      printf("%s '%s'\n", toys.which->name, s);
+      printf("%s '%s'\n", toys.which->name, s = dirtree_path(try, 0));
       free(s);
     }
 
@@ -246,13 +244,11 @@
       } else if (!S_ISREG(try->st.st_mode)
                  && (try->parent || (flags & (FLAG_a|FLAG_P|FLAG_r))))
       {
-        int i;
-
         // make symlink, or make block/char/fifo/socket
         if (S_ISLNK(try->st.st_mode)
-            ? ((i = readlinkat0(tfd, try->name, toybuf, sizeof(toybuf))) &&
-               ((!unlinkat(cfd, catch, 0) || ENOENT == errno) &&
-                !symlinkat(toybuf, cfd, catch)))
+            ? readlinkat0(tfd, try->name, toybuf, sizeof(toybuf)) &&
+              (!unlinkat(cfd, catch, 0) || ENOENT == errno) &&
+              !symlinkat(toybuf, cfd, catch)
             : !mknodat(cfd, catch, try->st.st_mode, try->st.st_rdev))
         {
           err = 0;
@@ -307,8 +303,6 @@
 
   // Did we make a thing?
   if (fdout != -1) {
-    int rc;
-
     // Inability to set --preserve isn't fatal, some require root access.
 
     // ownership
@@ -342,23 +336,21 @@
       xclose(fdout);
     }
 
-    if (CFG_MV && toys.which->name[0] == 'm')
+    if (save)
       if (unlinkat(tfd, try->name, S_ISDIR(try->st.st_mode) ? AT_REMOVEDIR :0))
         err = "%s";
   }
 
   if (err) {
-    char *f = 0;
-
     if (catch == try->name) {
-      f = dirtree_path(try, 0);
+      s = dirtree_path(try, 0);
       while (try->parent) try = try->parent;
-      catch = xmprintf("%s%s", TT.destname, f+strlen(try->name));
-      free(f);
-      f = catch;
-    }
+      catch = xmprintf("%s%s", TT.destname, s+strlen(try->name));
+      free(s);
+      s = catch;
+    } else s = 0;
     perror_msg(err, catch);
-    free(f);
+    free(s);
   }
   return 0;
 }
diff --git a/toys/posix/split.c b/toys/posix/split.c
index 5161aff..293343b 100644
--- a/toys/posix/split.c
+++ b/toys/posix/split.c
@@ -22,7 +22,7 @@
     -a	Suffix length (default 2)
     -b	BYTES/file (10, 10k, 10m, 10g...)
     -l	LINES/file (default 1000)
-    -n	PARTS
+    -n	PARTS many equal length files
 */
 
 #define FOR_split
@@ -42,14 +42,10 @@
 
   // posix doesn't cover permissions on output file, so copy input (or 0777)
   st.st_mode = 0777;
+  st.st_size = 0;
   fstat(infd, &st);
 
-  if (!TT.b && TT.n) {
-    if (lseek(infd, 0, SEEK_CUR) < 0)
-      error_exit("cannot determine file size");
-    TT.b = st.st_size / TT.n;
-  }
-
+  if (TT.n && (TT.b = st.st_size/TT.n)<1) return error_msg("%s: no size", in);
   len = pos = filenum = bytesleft = linesleft = 0;
   for (;;) {
     int i, j;
@@ -70,9 +66,7 @@
         j /= 26;
       }
       if (j) error_exit("bad suffix");
-      bytesleft = TT.b;
-      if (TT.n && filenum == TT.n && st.st_size % 2)
-          ++bytesleft;
+      bytesleft = TT.b + ((filenum == TT.n) ? st.st_size%TT.n : 0);
       linesleft = TT.l;
       xclose(outfd);
       outfd = xcreate(TT.outfile, O_RDWR|O_CREAT|O_TRUNC, st.st_mode & 0777);
diff --git a/toys/posix/tail.c b/toys/posix/tail.c
index 842814c..0d13ab0 100644
--- a/toys/posix/tail.c
+++ b/toys/posix/tail.c
@@ -6,7 +6,7 @@
  *
  * Deviations from posix: -f waits for pipe/fifo on stdin (nonblock?).
 
-USE_TAIL(NEWTOY(tail, "?fFs#=1c-n-[-cn][-fF]", TOYFLAG_USR|TOYFLAG_BIN))
+USE_TAIL(NEWTOY(tail, "?fFs:c-n-[-cn][-fF]", TOYFLAG_USR|TOYFLAG_BIN))
 
 config TAIL
   bool "tail"
@@ -27,18 +27,18 @@
 #define FOR_tail
 #include "toys.h"
 
-struct follow_file {
-  char *path;
-  int fd;
-  dev_t dev;
-  ino_t ino;
-};
-
 GLOBALS(
-  long n, c, s;
-  int file_no, last_fd;
+  long n, c;
+  char *s;
+
+  int file_no, last_fd, ss;
   struct xnotify *not;
-  struct follow_file *F;
+  struct {
+    char *path;
+    int fd;
+    dev_t dev;
+    ino_t ino;
+  } *F;
 )
 
 struct line_list {
@@ -132,66 +132,53 @@
   return 1;
 }
 
-static void show_new(int fd, char *path)
+// For -f and -F
+static void tail_continue()
 {
-  int len;
-
-  while ((len = read(fd, toybuf, sizeof(toybuf)))>0) {
-    if (TT.last_fd != fd) {
-      TT.last_fd = fd;
-      xprintf("\n==> %s <==\n", path);
-    }
-    xwrite(1, toybuf, len);
-  }
-}
-
-static void tail_F()
-{
+  long long pos;
+  char *path;
   struct stat sb;
-  int i, old_fd;
+  int i = 0, fd, len;
 
-  for (;;) {
-    for (i = 0; i<TT.file_no; ++i) {
-      old_fd = TT.F[i].fd;
-      if (stat(TT.F[i].path, &sb) != 0) {
-        if (old_fd >= 0) {
-          xprintf("tail: file inaccessible: %s\n", TT.F[i].path);
-          close(old_fd);
+  for (i = 0; ; i++) {
+    if (FLAG(f)) fd = xnotify_wait(TT.not, &path);
+    else {
+      if (i == TT.file_no) {
+        i = 0;
+        msleep(TT.ss);
+      }
+      fd = TT.F[i].fd;
+      path = TT.F[i].path;
+ 
+      if (stat(TT.F[i].path, &sb)) {
+        if (fd >= 0) {
+          close(fd);
           TT.F[i].fd = -1;
+          error_msg("file inaccessible: %s\n", TT.F[i].path);
         }
         continue;
       }
 
-      if (old_fd < 0 || sb.st_dev != TT.F[i].dev || sb.st_ino != TT.F[i].ino) {
-        if (old_fd >= 0) close(old_fd);
-        TT.F[i].fd = open(TT.F[i].path, O_RDONLY);
-        if (TT.F[i].fd == -1) continue;
-        else {
-          xprintf("tail: following new file: %s\n", TT.F[i].path);
-          TT.F[i].dev = sb.st_dev;
-          TT.F[i].ino = sb.st_ino;
-        }
-      } else if (sb.st_size && sb.st_size < lseek(TT.F[i].fd, 0, SEEK_CUR)) {
-        // If file was truncated, move to start.
-        xprintf("tail: file truncated: %s\n", TT.F[i].path);
-        xlseek(TT.F[i].fd, 0, SEEK_SET);
+      if (fd<0 || sb.st_dev!=TT.F[i].dev || sb.st_ino!=TT.F[i].ino) {
+        if (fd>=0) close(fd);
+        if (-1 == (TT.F[i].fd = fd = open(path, O_RDONLY))) continue;
+        error_msg("following new file: %s\n", path);
+        TT.F[i].dev = sb.st_dev;
+        TT.F[i].ino = sb.st_ino;
+      } else if (sb.st_size <= (pos = lseek(fd, 0, SEEK_CUR))) {
+        if (pos == sb.st_size) continue;
+        error_msg("file truncated: %s\n", path);
+        lseek(fd, 0, SEEK_SET);
       }
-
-      show_new(TT.F[i].fd, TT.F[i].path);
     }
 
-    sleep(TT.s);
-  }
-}
-
-static void tail_f()
-{
-  char *path;
-  int fd;
-
-  for (;;) {
-    fd = xnotify_wait(TT.not, &path);
-    show_new(fd, path);
+    while ((len = read(fd, toybuf, sizeof(toybuf)))>0) {
+      if (TT.file_no>1 && TT.last_fd != fd) {
+        TT.last_fd = fd;
+        xprintf("\n==> %s <==\n", path);
+      }
+      xwrite(1, toybuf, len);
+    }
   }
 }
 
@@ -201,6 +188,9 @@
   long bytes = TT.c, lines = TT.n;
   int linepop = 1;
 
+  if (FLAG(F)) {
+    if (!fd) perror_exit("no -F with '-'");
+  } else if (fd == -1) return;
   if (FLAG(f) || FLAG(F)) {
     char *s = name;
     struct stat sb;
@@ -209,11 +199,13 @@
 
     if (FLAG(f)) xnotify_add(TT.not, fd, s);
     if (FLAG(F)) {
-      if (fstat(fd, &sb) != 0) perror_exit("%s", name);
+      if (fd != -1) {
+        if (fstat(fd, &sb)) perror_exit("%s", name);
+        TT.F[TT.file_no].dev = sb.st_dev;
+        TT.F[TT.file_no].ino = sb.st_ino;
+      }
       TT.F[TT.file_no].fd = fd;
       TT.F[TT.file_no].path = s;
-      TT.F[TT.file_no].dev = sb.st_dev;
-      TT.F[TT.file_no].ino = sb.st_ino;
     }
   }
 
@@ -298,23 +290,21 @@
   if (!FLAG(n) && !FLAG(c)) {
     char *arg = *args;
 
-    // handle old "-42" style arguments
+    // handle old "-42" style arguments, else default to last 10 lines
     if (arg && *arg == '-' && arg[1]) {
       TT.n = atolx(*(args++));
       toys.optc--;
-    } else {
-      // if nothing specified, default -n to -10
-      TT.n = -10;
-    }
+    } else TT.n = -10;
   }
 
-  if (FLAG(F)) TT.F = xmalloc(toys.optc * sizeof(struct follow_file));
+  if (FLAG(F)) TT.F = xzalloc(toys.optc*sizeof(*TT.F));
   else if (FLAG(f)) TT.not = xnotify_init(toys.optc);
+  TT.ss = TT.s ? xparsemillitime(TT.s) : 1000;
 
-  loopfiles_rw(args, O_RDONLY|WARN_ONLY|(O_CLOEXEC*!(FLAG(f) || FLAG(F))), 0, do_tail);
+  loopfiles_rw(args,
+    O_RDONLY|WARN_ONLY|LOOPFILES_ANYWAY|(O_CLOEXEC*!(FLAG(f) || FLAG(F))),
+    0, do_tail);
 
-  if (TT.file_no) {
-    if (FLAG(F)) tail_F();
-    else if (FLAG(f)) tail_f();
-  }
+  // Wait for more data when following files
+  if (TT.file_no && (FLAG(F) || FLAG(f))) tail_continue();
 }