Sh

- regression in cpu usage [339](https://github.com/amoffat/sh/issues/339)

- fd leak regression and fix for flawed fd leak detection test [337](https://github.com/amoffat/sh/pull/337)

- support for `io.StringIO` in python2

- added support for using raw file descriptors for `_in`, `_out`, and `_err`
- removed `.close()`ing `_out` handler if FIFO detected

- composed commands no longer propagate `_bg`
- better support for using `sys.stdin` and `sys.stdout` for `_in` and `_out`
- bugfix where `which()` would not stop searching at the first valid executable found in PATH
- added `_long_prefix` for programs whose long arguments start with something other than `--` [278](https://github.com/amoffat/sh/pull/278)
- added `_log_msg` for advanced configuration of log message [311](https://github.com/amoffat/sh/pull/311)
- added `sh.contrib.sudo`
- added `_arg_preprocess` for advanced command wrapping
- alter callable `_in` arguments to signify completion with falsy chunk
- bugfix where pipes passed into `_out` or `_err` were not flushed on process end [252](https://github.com/amoffat/sh/pull/252)
- deprecated `with sh.args(**kwargs)` in favor of `sh2 = sh(**kwargs)`
- made `sh.pushd` thread safe
- added `.kill_group()` and `.signal_group()` methods for better process control [237](https://github.com/amoffat/sh/pull/237)
- added `new_session` special keyword argument for controlling spawned process session [266](https://github.com/amoffat/sh/issues/266)
- bugfix better handling for EINTR on system calls [292](https://github.com/amoffat/sh/pull/292)
- bugfix where with-contexts were not threadsafe [247](https://github.com/amoffat/sh/issues/195)
- `_uid` new special keyword param for specifying the user id of the process [133](https://github.com/amoffat/sh/issues/133)
- bugfix where exceptions were swallowed by processes that weren't waited on [309](https://github.com/amoffat/sh/issues/309)
- bugfix where processes that dupd their stdout/stderr to a long running child process would cause sh to hang [310](https://github.com/amoffat/sh/issues/310)
- improved logging output [323](https://github.com/amoffat/sh/issues/323)
- bugfix for python3+ where binary data was passed into a process's stdin [325](https://github.com/amoffat/sh/issues/325)
- Introduced execution contexts which allow baking of common special keyword arguments into all commands [269](https://github.com/amoffat/sh/issues/269)
- `Command` and `which` now can take an optional `paths` parameter which specifies the search paths [226](https://github.com/amoffat/sh/issues/226)
- `_preexec_fn` option for executing a function after the child process forks but before it execs [260](https://github.com/amoffat/sh/issues/260)
- `_fg` reintroduced, with limited functionality. hurrah! [92](https://github.com/amoffat/sh/issues/92)
- bugfix where a command would block if passed a fd for stdin that wasn't yet ready to read [253](https://github.com/amoffat/sh/issues/253)
- `_long_sep` can now take `None` which splits the long form arguments into individual arguments [258](https://github.com/amoffat/sh/issues/258)
- making `_piped` perform "direct" piping by default (linking fds together). this fixes memory problems [270](https://github.com/amoffat/sh/issues/270)
- bugfix where calling `next()` on an iterable process that has raised `StopIteration`, hangs [273](https://github.com/amoffat/sh/issues/273)
- `sh.cd` called with no arguments no changes into the user's home directory, like native `cd` [275](https://github.com/amoffat/sh/issues/275)
- `sh.glob` removed entirely. the rationale is correctness over hand-holding. [279](https://github.com/amoffat/sh/issues/279)
- added `_truncate_exc`, defaulting to `True`, which tells our exceptions to truncate output.
- bugfix for exceptions whose messages contained unicode
- `_done` callback no longer assumes you want your command put in the background.
- `_done` callback is now called asynchronously in a separate thread.
- `_done` callback is called regardless of exception, which is necessary in order to release held resources, for example a process pool

- partially applied functions with `functools.partial` have been fixed for `_out` and `_err` callbacks [160](https://github.com/amoffat/sh/issues/160)
- `_out` or `_err` being callables no longer puts the running command in the background. to achieve the previous behavior, pass `_bg=True` to your command.
- deprecated `_with` contexts [195](https://github.com/amoffat/sh/issues/195)
- `_timeout_signal` allows you to specify your own signal to kill a timed-out process with. use a constant from the `signal` stdlib module. [171](https://github.com/amoffat/sh/issues/171)
- signal exceptions can now be caught by number or name. `SignalException_9 == SignalException_SIGKILL`
- child processes that timeout via `_timeout` raise `sh.TimeoutException` instead of `sh.SignalExeception_9` [172](https://github.com/amoffat/sh/issues/172)
- fixed `help(sh)` from the python shell and `pydoc sh` from the command line. [173](https://github.com/amoffat/sh/issues/173)
- program names can no longer be shadowed by names that sh.py defines internally. removed the requirement of trailing underscores for programs that could have their names shadowed, like `id`.
- memory optimization when a child process's stdin is a newline-delimted string and our bufsize is newlines
- feature, `_done` special keyword argument that accepts a callback to be called when the command completes successfully [185](https://github.com/amoffat/sh/issues/185)
- bugfix for being unable to print a baked command in python3+ [176](https://github.com/amoffat/sh/issues/176)
- bugfix for cwd not existing and causing the child process to continue running parent process code [202](https://github.com/amoffat/sh/issues/202)
- child process is now guaranteed to exit on exception between fork and exec.
- fix python2 deprecation warning when running with -3 [PR 165](https://github.com/amoffat/sh/pull/165)
- bugfix where sh.py was attempting to execute directories [196](https://github.com/amoffat/sh/issues/196), [PR #189](https://github.com/amoffat/sh/pull/189)
- only backgrounded processes will ignore SIGHUP
- allowed `ok_code` to take a `range` object. [PR 210](https://github.com/amoffat/sh/pull/210/files)
- added `sh.args` with context which allows overriding of all command defaults for the duration of that context.
- added `sh.pushd` with context which takes a directory name and changes to that directory for the duration of that with context. [PR 206](https://github.com/amoffat/sh/pull/206)
- tests now include python 3.4 if available. tests also stop on the first
python that suite that fails.
- SIGABRT, SIGBUS, SIGFPE, SIGILL, SIGPIPE, SIGSYS have been added to the list of signals that throw an exception [PR 201](https://github.com/amoffat/sh/pull/201)
- "callable" builtin has been faked for python3.1, which lacks it.
- "direct" option added to `_piped` special keyword argument, which allows sh to hand off a process's stdout fd directly to another process, instead of buffering its stdout internally, then handing it off. [119](https://github.com/amoffat/sh/issues/119)