diff --git a/.meta/.readme.rst b/.meta/.readme.rst
index 1746daa84..75d83a6aa 100644
--- a/.meta/.readme.rst
+++ b/.meta/.readme.rst
@@ -272,6 +272,16 @@ Or done on a file level using 7-zip:
       | grep -v Compressing
     100%|██████████████████████████▉| 15327/15327 [01:00<00:00, 712.96files/s]
 
+Pre-existing CLI programs already outputting basic progress information will
+benefit from ``tqdm``'s ``--update`` and ``--update_to`` flags:
+
+.. code:: sh
+
+    seq 3 0.1 5 | tqdm --total 5 --update_to --null
+    100%|████████████████████████████████████| 5.0/5 [00:00<00:00, 9673.21it/s]
+    seq 10 | tqdm --update --null  # 1 + 2 + ... + 10 = 55 iterations
+    55it [00:00, 90006.52it/s]
+
 FAQ and Known Issues
 --------------------
 
diff --git a/Makefile b/Makefile
index f0c5e5f8f..d9091cad0 100644
--- a/Makefile
+++ b/Makefile
@@ -91,6 +91,7 @@ tqdm/tqdm.1: .meta/.tqdm.1.md tqdm/cli.py tqdm/std.py
 	python -m tqdm --help | tail -n+5 |\
     sed -r -e 's/\\/\\\\/g' \
       -e 's/^  (--.*)=<(.*)>  : (.*)$$/\n\\\1=*\2*\n: \3./' \
+      -e 's/^  (--.*)  : (.*)$$/\n\\\1\n: \2./' \
       -e 's/  (-.*, )(--.*)  /\n\1\\\2\n: /' |\
     cat "$<" - |\
     pandoc -o "$@" -s -t man
diff --git a/README.rst b/README.rst
index 5fa363e80..ac43c547b 100644
--- a/README.rst
+++ b/README.rst
@@ -272,6 +272,16 @@ Or done on a file level using 7-zip:
       | grep -v Compressing
     100%|██████████████████████████▉| 15327/15327 [01:00<00:00, 712.96files/s]
 
+Pre-existing CLI programs already outputting basic progress information will
+benefit from ``tqdm``'s ``--update`` and ``--update_to`` flags:
+
+.. code:: sh
+
+    seq 3 0.1 5 | tqdm --total 5 --update_to --null
+    100%|████████████████████████████████████| 5.0/5 [00:00<00:00, 9673.21it/s]
+    seq 10 | tqdm --update --null  # 1 + 2 + ... + 10 = 55 iterations
+    55it [00:00, 90006.52it/s]
+
 FAQ and Known Issues
 --------------------
 
@@ -465,6 +475,14 @@ Extra CLI Options
     ``unit_scale`` to True, ``unit_divisor`` to 1024, and ``unit`` to 'B'.
 * tee  : bool, optional  
     If true, passes ``stdin`` to both ``stderr`` and ``stdout``.
+* update  : bool, optional  
+    If true, will treat input as newly elapsed iterations,
+    i.e. numbers to pass to ``update()``.
+* update_to  : bool, optional  
+    If true, will treat input as total elapsed iterations,
+    i.e. numbers to assign to ``self.n``.
+* null  : bool, optional  
+    If true, will discard input (no stdout).
 * manpath  : str, optional  
     Directory in which to install tqdm man pages.
 * comppath  : str, optional  
diff --git a/tqdm/cli.py b/tqdm/cli.py
index 4b8f96c94..db90e7a00 100644
--- a/tqdm/cli.py
+++ b/tqdm/cli.py
@@ -3,14 +3,15 @@
 """
 from .std import tqdm, TqdmTypeError, TqdmKeyError
 from ._version import __version__  # NOQA
-import sys
-import re
+from ast import literal_eval as numeric
 import logging
+import re
+import sys
 __all__ = ["main"]
+log = logging.getLogger(__name__)
 
 
 def cast(val, typ):
-    log = logging.getLogger(__name__)
     log.debug((val, typ))
     if " or " in typ:
         for t in typ.split(" or "):
@@ -47,14 +48,16 @@ def isBytes(val):
 
 
 def posix_pipe(fin, fout, delim=b'\\n', buf_size=256,
-               callback=lambda int: None  # pragma: no cover
-               ):
+               callback=lambda float: None,  # pragma: no cover
+               callback_len=True):
     """
     Params
     ------
     fin  : file with `read(buf_size : int)` method
     fout  : file with `write` (and optionally `flush`) methods.
-    callback  : function(int), e.g.: `tqdm.update`
+    callback  : function(float), e.g.: `tqdm.update`
+    callback_len  : If (default: True) do `callback(len(buffer))`.
+      Otherwise, do `callback(data) for data in buffer.split(delim)`.
     """
     fp_write = fout.write
 
@@ -92,7 +95,12 @@ def posix_pipe(fin, fout, delim=b'\\n', buf_size=256,
         if not tmp:
             if buf:
                 fp_write(buf)
-                callback(1 + buf.count(delim))  # n += 1 + buf.count(delim)
+                if callback_len:
+                    # n += 1 + buf.count(delim)
+                    callback(1 + buf.count(delim))
+                else:
+                    for i in buf.split(delim):
+                        callback(i)
             getattr(fout, 'flush', lambda: None)()  # pragma: no cover
             return  # n
 
@@ -104,7 +112,8 @@ def posix_pipe(fin, fout, delim=b'\\n', buf_size=256,
                 break
             else:
                 fp_write(buf + tmp[:i + len(delim)])
-                callback(1)  # n += 1
+                # n += 1
+                callback(1 if callback_len else (buf + tmp[:i]))
                 buf = b'' if write_bytes else ''
                 tmp = tmp[i + len(delim):]
 
@@ -134,6 +143,14 @@ def posix_pipe(fin, fout, delim=b'\\n', buf_size=256,
             `unit_scale` to True, `unit_divisor` to 1024, and `unit` to 'B'.
         tee  : bool, optional
             If true, passes `stdin` to both `stderr` and `stdout`.
+        update  : bool, optional
+            If true, will treat input as newly elapsed iterations,
+            i.e. numbers to pass to `update()`.
+        update_to  : bool, optional
+            If true, will treat input as total elapsed iterations,
+            i.e. numbers to assign to `self.n`.
+        null  : bool, optional
+            If true, will discard input (no stdout).
         manpath  : str, optional
             Directory in which to install tqdm man pages.
         comppath  : str, optional
@@ -153,7 +170,7 @@ def main(fp=sys.stderr, argv=None):
     if argv is None:
         argv = sys.argv[1:]
     try:
-        log = argv.index('--log')
+        log_idx = argv.index('--log')
     except ValueError:
         for i in argv:
             if i.startswith('--log='):
@@ -162,13 +179,12 @@ def main(fp=sys.stderr, argv=None):
         else:
             logLevel = 'INFO'
     else:
-        # argv.pop(log)
-        # logLevel = argv.pop(log)
-        logLevel = argv[log + 1]
+        # argv.pop(log_idx)
+        # logLevel = argv.pop(log_idx)
+        logLevel = argv[log_idx + 1]
     logging.basicConfig(
         level=getattr(logging, logLevel),
         format="%(levelname)s:%(module)s:%(lineno)d:%(message)s")
-    log = logging.getLogger(__name__)
 
     d = tqdm.__init__.__doc__ + CLI_EXTRA_DOC
 
@@ -183,16 +199,17 @@ def main(fp=sys.stderr, argv=None):
     # d = RE_OPTS.sub(r'  --\1=<\1>  : \2', d)
     split = RE_OPTS.split(d)
     opt_types_desc = zip(split[1::3], split[2::3], split[3::3])
-    d = ''.join('\n  --{0}=<{0}>  : {1}{2}'.format(*otd)
+    d = ''.join(('\n  --{0}  : {2}{3}' if otd[1] == 'bool' else
+                 '\n  --{0}=<{1}>  : {2}{3}').format(
+                     otd[0].replace('_', '-'), otd[0], *otd[1:])
                 for otd in opt_types_desc if otd[0] not in UNSUPPORTED_OPTS)
 
     d = """Usage:
   tqdm [--help | options]
 
 Options:
-  -h, --help     Print this help and exit
-  -v, --version  Print version and exit
-
+  -h, --help     Print this help and exit.
+  -v, --version  Print version and exit.
 """ + d.strip('\n') + '\n'
 
     # opts = docopt(d, version=__version__)
@@ -212,11 +229,19 @@ def main(fp=sys.stderr, argv=None):
     tqdm_args = {'file': fp}
     try:
         for (o, v) in opts.items():
+            o = o.replace('-', '_')
             try:
                 tqdm_args[o] = cast(v, opt_types[o])
             except KeyError as e:
                 raise TqdmKeyError(str(e))
         log.debug('args:' + str(tqdm_args))
+
+        delim_per_char = tqdm_args.pop('bytes', False)
+        update = tqdm_args.pop('update', False)
+        update_to = tqdm_args.pop('update_to', False)
+        if sum((delim_per_char, update, update_to)) > 1:
+            raise TqdmKeyError(
+                "Can only have one of --bytes --update --update_to")
     except:
         fp.write('\nError:\nUsage:\n  tqdm [--help | options]\n')
         for i in sys.stdin:
@@ -225,12 +250,18 @@ def main(fp=sys.stderr, argv=None):
     else:
         buf_size = tqdm_args.pop('buf_size', 256)
         delim = tqdm_args.pop('delim', b'\\n')
-        delim_per_char = tqdm_args.pop('bytes', False)
         tee = tqdm_args.pop('tee', False)
         manpath = tqdm_args.pop('manpath', None)
         comppath = tqdm_args.pop('comppath', None)
+        if tqdm_args.pop('null', False):
+            class stdout(object):
+                @staticmethod
+                def write(_):
+                    pass
+        else:
+            stdout = sys.stdout
+            stdout = getattr(stdout, 'buffer', stdout)
         stdin = getattr(sys.stdin, 'buffer', sys.stdin)
-        stdout = getattr(sys.stdout, 'buffer', sys.stdout)
         if manpath or comppath:
             from os import path
             from shutil import copyfile
@@ -267,9 +298,32 @@ def write(x):
                 posix_pipe(stdin, stdout, '', buf_size, t.update)
         elif delim == b'\\n':
             log.debug(tqdm_args)
-            for i in tqdm(stdin, **tqdm_args):
-                stdout.write(i)
+            if update or update_to:
+                with tqdm(**tqdm_args) as t:
+                    if update:
+                        def callback(i):
+                            t.update(numeric(i))
+                    else:  # update_to
+                        def callback(i):
+                            t.update(numeric(i) - t.n)
+                    for i in stdin:
+                        stdout.write(i)
+                        callback(i)
+            else:
+                for i in tqdm(stdin, **tqdm_args):
+                    stdout.write(i)
         else:
             log.debug(tqdm_args)
             with tqdm(**tqdm_args) as t:
-                posix_pipe(stdin, stdout, delim, buf_size, t.update)
+                callback_len = False
+                if update:
+                    def callback(i):
+                        t.update(numeric(i))
+                elif update_to:
+                    def callback(i):
+                        t.update(numeric(i) - t.n)
+                else:
+                    callback = t.update
+                    callback_len = True
+                posix_pipe(stdin, stdout, delim, buf_size,
+                           callback, callback_len)
diff --git a/tqdm/completion.sh b/tqdm/completion.sh
index c6304ab73..42e84a8b5 100755
--- a/tqdm/completion.sh
+++ b/tqdm/completion.sh
@@ -12,7 +12,7 @@ _tqdm(){
     COMPREPLY=($(compgen -W       'CRITICAL FATAL ERROR WARN WARNING INFO DEBUG NOTSET' -- ${cur}))
     ;;
   *)
-    COMPREPLY=($(compgen -W '--ascii --bar_format --buf_size --bytes --comppath --delim --desc --disable --dynamic_ncols --help --initial --leave --lock_args --log --manpath --maxinterval --mininterval --miniters --ncols --nrows --position --postfix --smoothing --tee --total --unit --unit_divisor --unit_scale --version --write_bytes -h -v' -- ${cur}))
+    COMPREPLY=($(compgen -W '--ascii --bar_format --buf_size --bytes --comppath --delim --desc --disable --dynamic_ncols --help --initial --leave --lock_args --log --manpath --maxinterval --mininterval --miniters --ncols --nrows --null --position --postfix --smoothing --tee --total --unit --unit_divisor --unit_scale --update --update_to --version --write_bytes -h -v' -- ${cur}))
     ;;
   esac
 }
diff --git a/tqdm/tests/tests_main.py b/tqdm/tests/tests_main.py
index dbbf3c16a..08eccc05b 100644
--- a/tqdm/tests/tests_main.py
+++ b/tqdm/tests/tests_main.py
@@ -47,16 +47,17 @@ def test_pipes():
 def test_main():
     """Test misc CLI options"""
     _SYS = sys.stdin, sys.argv
+    N = 123
 
     # test direct import
-    sys.stdin = map(str, _range(int(123)))
+    sys.stdin = map(str, _range(N))
     sys.argv = ['', '--desc', 'Test CLI import',
                 '--ascii', 'True', '--unit_scale', 'True']
     import tqdm.__main__  # NOQA
     sys.stderr.write("Test misc CLI options ... ")
 
     # test --delim
-    IN_DATA = '\0'.join(map(str, _range(int(123))))
+    IN_DATA = '\0'.join(map(str, _range(N)))
     with closing(StringIO()) as sys.stdin:
         sys.argv = ['', '--desc', 'Test CLI delim',
                     '--ascii', 'True', '--delim', r'\0', '--buf_size', '64']
@@ -65,7 +66,7 @@ def test_main():
         sys.stdin.seek(0)
         with closing(UnicodeIO()) as fp:
             main(fp=fp)
-            assert "123it" in fp.getvalue()
+            assert str(N) + "it" in fp.getvalue()
 
     # test --bytes
     IN_DATA = IN_DATA.replace('\0', '\n')
@@ -78,7 +79,7 @@ def test_main():
             assert str(len(IN_DATA)) in fp.getvalue()
 
     # test --log
-    sys.stdin = map(str, _range(int(123)))
+    sys.stdin = map(str, _range(N))
     # with closing(UnicodeIO()) as fp:
     main(argv=['--log', 'DEBUG'], fp=NULL)
     # assert "DEBUG:" in sys.stdout.getvalue()
@@ -99,6 +100,85 @@ def test_main():
             # spaces to clear intermediate lines could increase length
             assert len(fp.getvalue()) >= res + len(IN_DATA)
 
+    # test --null
+    _STDOUT = sys.stdout
+    try:
+        with closing(StringIO()) as sys.stdout:
+            with closing(StringIO()) as sys.stdin:
+                sys.stdin.write(IN_DATA)
+
+                sys.stdin.seek(0)
+                with closing(UnicodeIO()) as fp:
+                    main(argv=['--null'], fp=fp)
+                    assert not sys.stdout.getvalue()
+
+            with closing(StringIO()) as sys.stdin:
+                sys.stdin.write(IN_DATA)
+
+                sys.stdin.seek(0)
+                with closing(UnicodeIO()) as fp:
+                    main(argv=[], fp=fp)
+                    assert sys.stdout.getvalue()
+    except:
+        sys.stdout = _STDOUT
+        raise
+    else:
+        sys.stdout = _STDOUT
+
+    # test integer --update
+    with closing(StringIO()) as sys.stdin:
+        sys.stdin.write(IN_DATA)
+
+        sys.stdin.seek(0)
+        with closing(UnicodeIO()) as fp:
+            main(argv=['--update'], fp=fp)
+            res = fp.getvalue()
+            assert str(N // 2 * N) + "it" in res  # arithmetic sum formula
+
+    # test integer --update --delim
+    with closing(StringIO()) as sys.stdin:
+        sys.stdin.write(IN_DATA.replace('\n', 'D'))
+
+        sys.stdin.seek(0)
+        with closing(UnicodeIO()) as fp:
+            main(argv=['--update', '--delim', 'D'], fp=fp)
+            res = fp.getvalue()
+            assert str(N // 2 * N) + "it" in res  # arithmetic sum formula
+
+    # test integer --update_to
+    with closing(StringIO()) as sys.stdin:
+        sys.stdin.write(IN_DATA)
+
+        sys.stdin.seek(0)
+        with closing(UnicodeIO()) as fp:
+            main(argv=['--update-to'], fp=fp)
+            res = fp.getvalue()
+            assert str(N - 1) + "it" in res
+            assert str(N) + "it" not in res
+
+    # test integer --update_to --delim
+    with closing(StringIO()) as sys.stdin:
+        sys.stdin.write(IN_DATA.replace('\n', 'D'))
+
+        sys.stdin.seek(0)
+        with closing(UnicodeIO()) as fp:
+            main(argv=['--update-to', '--delim', 'D'], fp=fp)
+            res = fp.getvalue()
+            assert str(N - 1) + "it" in res
+            assert str(N) + "it" not in res
+
+    # test float --update_to
+    IN_DATA = '\n'.join((str(i / 2.0) for i in _range(N)))
+    with closing(StringIO()) as sys.stdin:
+        sys.stdin.write(IN_DATA)
+
+        sys.stdin.seek(0)
+        with closing(UnicodeIO()) as fp:
+            main(argv=['--update-to'], fp=fp)
+            res = fp.getvalue()
+            assert str((N - 1) / 2.0) + "it" in res
+            assert str(N / 2.0) + "it" not in res
+
     # clean up
     sys.stdin, sys.argv = _SYS
 
@@ -150,7 +230,7 @@ def test_comppath():
 def test_exceptions():
     """Test CLI Exceptions"""
     _SYS = sys.stdin, sys.argv
-    sys.stdin = map(str, _range(int(123)))
+    sys.stdin = map(str, _range(123))
 
     sys.argv = ['', '-ascii', '-unit_scale', '--bad_arg_u_ment', 'foo']
     try:
@@ -179,6 +259,15 @@ def test_exceptions():
     else:
         raise TqdmTypeError('invalid_int_value')
 
+    sys.argv = ['', '--update', '--update_to']
+    try:
+        main(fp=NULL)
+    except TqdmKeyError as e:
+        if 'Can only have one of --' not in str(e):
+            raise
+    else:
+        raise TqdmKeyError('Cannot have both --update --update_to')
+
     # test SystemExits
     for i in ('-h', '--help', '-v', '--version'):
         sys.argv = ['', i]
diff --git a/tqdm/tqdm.1 b/tqdm/tqdm.1
index c983d20d1..e8dadade2 100644
--- a/tqdm/tqdm.1
+++ b/tqdm/tqdm.1
@@ -36,12 +36,12 @@ counting:\ 100%|█████████|\ 432/432\ [00:00<00:00,\ 794361.83f
 .SH OPTIONS
 .TP
 .B \-h, \-\-help
-Print this help and exit
+Print this help and exit.
 .RS
 .RE
 .TP
 .B \-v, \-\-version
-Print version and exit
+Print version and exit.
 .RS
 .RE
 .TP
@@ -63,7 +63,7 @@ specify an initial arbitrary large positive number, e.g.
 .RS
 .RE
 .TP
-.B \-\-leave=\f[I]leave\f[]
+.B \-\-leave
 bool, optional.
 If [default: True], keeps all traces of the progressbar upon termination
 of iteration.
@@ -117,7 +117,7 @@ The fallback is to use ASCII characters " 123456789#".
 .RS
 .RE
 .TP
-.B \-\-disable=\f[I]disable\f[]
+.B \-\-disable
 bool, optional.
 Whether to disable the entire progressbar wrapper [default: False].
 If set to None, disable on non\-TTY.
@@ -131,7 +131,7 @@ it].
 .RS
 .RE
 .TP
-.B \-\-unit_scale=\f[I]unit_scale\f[]
+.B \-\-unit\-scale=\f[I]unit_scale\f[]
 bool or int or float, optional.
 If 1 or True, the number of iterations will be reduced/scaled
 automatically and a metric prefix following the International System of
@@ -140,7 +140,7 @@ If any other non\-zero number, will scale \f[C]total\f[] and \f[C]n\f[].
 .RS
 .RE
 .TP
-.B \-\-dynamic_ncols=\f[I]dynamic_ncols\f[]
+.B \-\-dynamic\-ncols
 bool, optional.
 If set, constantly alters \f[C]ncols\f[] and \f[C]nrows\f[] to the
 environment (allowing for window resizes) [default: False].
@@ -156,7 +156,7 @@ Ranges from 0 (average speed) to 1 (current/instantaneous speed)
 .RS
 .RE
 .TP
-.B \-\-bar_format=\f[I]bar_format\f[]
+.B \-\-bar\-format=\f[I]bar_format\f[]
 str, optional.
 Specify a custom bar string formatting.
 May impact performance.
@@ -196,13 +196,13 @@ Calls \f[C]set_postfix(**postfix)\f[] if possible (dict).
 .RS
 .RE
 .TP
-.B \-\-unit_divisor=\f[I]unit_divisor\f[]
+.B \-\-unit\-divisor=\f[I]unit_divisor\f[]
 float, optional.
 [default: 1000], ignored unless \f[C]unit_scale\f[] is True.
 .RS
 .RE
 .TP
-.B \-\-write_bytes=\f[I]write_bytes\f[]
+.B \-\-write\-bytes
 bool, optional.
 If (default: None) and \f[C]file\f[] is unspecified, bytes will be
 written in Python 2.
@@ -211,7 +211,7 @@ In all other cases will default to unicode.
 .RS
 .RE
 .TP
-.B \-\-lock_args=\f[I]lock_args\f[]
+.B \-\-lock\-args=\f[I]lock_args\f[]
 tuple, optional.
 Passed to \f[C]refresh\f[] for intermediate output (initialisation,
 iterating, and updating).
@@ -236,14 +236,14 @@ N.B.: on Windows systems, Python converts \[aq]\\n\[aq] to
 .RS
 .RE
 .TP
-.B \-\-buf_size=\f[I]buf_size\f[]
+.B \-\-buf\-size=\f[I]buf_size\f[]
 int, optional.
 String buffer size in bytes [default: 256] used when \f[C]delim\f[] is
 specified.
 .RS
 .RE
 .TP
-.B \-\-bytes=\f[I]bytes\f[]
+.B \-\-bytes
 bool, optional.
 If true, will count bytes, ignore \f[C]delim\f[], and default
 \f[C]unit_scale\f[] to True, \f[C]unit_divisor\f[] to 1024, and
@@ -251,13 +251,33 @@ If true, will count bytes, ignore \f[C]delim\f[], and default
 .RS
 .RE
 .TP
-.B \-\-tee=\f[I]tee\f[]
+.B \-\-tee
 bool, optional.
 If true, passes \f[C]stdin\f[] to both \f[C]stderr\f[] and
 \f[C]stdout\f[].
 .RS
 .RE
 .TP
+.B \-\-update
+bool, optional.
+If true, will treat input as newly elapsed iterations, i.e.
+numbers to pass to \f[C]update()\f[].
+.RS
+.RE
+.TP
+.B \-\-update\-to
+bool, optional.
+If true, will treat input as total elapsed iterations, i.e.
+numbers to assign to \f[C]self.n\f[].
+.RS
+.RE
+.TP
+.B \-\-null
+bool, optional.
+If true, will discard input (no stdout).
+.RS
+.RE
+.TP
 .B \-\-manpath=\f[I]manpath\f[]
 str, optional.
 Directory in which to install tqdm man pages.