- 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