ChangeLog

Changes since 1.2: (Too many to count!)

A memory stomping bug was fixed (provoked by assigning a variable
to its old value plus something else).

Better signal handling; a real signal handler which manages a queue
of pending signals was added.

rc now ignores SIGQUIT and traps SIGINT even in non-interactive
mode. Thus,

	rc ed.sh

will not do mysterious things if the shell script "ed.sh" calls a
command like "ed" and then you hit ^C.

rc now opens 0, 1, 2 on /dev/null if they are inherited closed.
rc -o prevents this.

A couple of stupid O(n^2) string appends were replaced with O(n)
loops. This should make foo=`{cat /etc/termcap} bar=$^foo a little
faster :-)

Returning a list of signals from a function is now legal, so "return
$status" should always work.

The code has been revised, new printing routines have been added.

rc no longer uses redundant braces when exporting functions.

A first stab at a verification suite has been added (trip.rc).
(someone, please help me make this comprehensive!)

rc -p now does not initialize functions from the environment. This
should make it easier to write shell scripts that don't need to
assume anything about the environment.

Inherited ignored signals are now ignored in the current shell and
passed on ignored to the child processes. whatis -s also reflects
this information.

A file descriptor leak in the /dev/fd implementation of >{} was
fixed.

A variable set to '' was not imported from the environment; this
has been fixed.

Changes since 1.3beta:

New Makefile/config.h setup.

builtin echo may now be conditionally included out, to use a Goldwynism.

builtin exit takes any legal exit status. If the status is not all zeros,
rc exits with 1. (having "exit sigiot" produce a core dump would be going
a little far, I think.)

limit does not append a unit after a zero limit; 0g was too confusing.

exec > /nonexistentfile does not cause rc to exit any more.

If a noninteractive rc is started with sigint ignored, rc does not install
its own signal handler.

error messages produced by rc in a subshell were cleaned up. (rc erroneously
reset the 'interactive' flag after a fork)

print.c was cleaned up a little; no functionality was changed, but should
be more portable now.

a bug in rc-1.3beta (not previous versions) was fixed: setting the first
element of $path to '' caused PATH to be exported as '':etc..

getopt's "illegal option" message was gratuitously changed to something
less abrupt.

some dead code was removed from input.c

%term was changed to %token in parse.y; apparently newer yacc's don't grok
%term any more.

a race condition in the signal handler was fixed.

the variable in for() was getting evaluated each time through the loop
(e.g., for (`{echo i;date>[1=2]} in 1 2 3)echo $i would print the date
three times). This was cleaned up.

a redundant fork() was removed from walk.c; this showed up when running
a braced command with a redirection in the background. e.g., {a;b}>c&

man pages for history and rc were cleaned up by david (thanks).

rc set SIGQUIT and SIGTERM to SIG_DFL on background jobs---even when
trying to do old-style backgrounding (i.e., don't use process groups,
just ignore SIGINT & SIGQUIT & SIGTERM).

$0 is now changed to the name of the signal when entering a signal
handler. Thus it's possible to write code like

	fn sigint sigterm sigquit {
		switch ($0) {
		case sigint
			...
		case sigterm
			...

wait with no arguments now prints the pid of any and all children
that died with a signal. e.g.,

	; wait
	25321: terminated
	25325: terminated

as opposed to

	; wait
	terminated

An error saving/restoring state in the input stream code would
cause rc to exit with the (erroneous) command:

	eval '|[a'

FIFO's were not removed in a backgrounded command, e.g.,

	cat <{echo hi}&

Changes since rc-1.4beta:

getopt was renamed to rc_getopt to avoid libc collisions.

$cdpath with a / in it caused a cd to sometimes have two //'s at the
front of the path. This is reserved by POSIX, so I changed it to skip
one of the /'s.

signal handling now emulates sh in the way I described in a previous
message: the race condition present in older rc's whereby some SIGINTs
got lost is now gone; any SIGINT received during a wait() is acted upon
at the end of the wait(), unless of course SIGINT is being deliberately
ignored.

getopt was renamed to avoid naming conflicts with libc. Also a sound
move since rc_getopt is no longer quite libc-getopt compatible; I had
to add in a mechanism for resetting getopt.

signal handler code in fn.c was cleaned up; there were several bugs
in rc-1.4beta, notably the shell sometimes spawned background jobs
with SIGTERM ignored. I took the opportunity to make things a little
cleaner here.

a quasi-memory leak in the code for while() was fixed: a long-running
while that had rc commands allocating memory in it could cause the
shell to grow without bounds. I fixed this by placing the while loop
(*and* test!) inside a new allocation arena each time through the loop.

A new configuration parameter, NOJOB, was added to allow you to force
v7-style backgrounding (no setpgrp, ignore SIGINT and SIGTERM).

The FIFO code was reworked a little. It should be more robust now---
FIFOs get removed at the end of the command of the argument list
that they were on:

		fn foo {echo $*; cat $*}
		foo<{echo hi}

now works as expected. Also FIFO names are pushed onto the exception
stack so that their removal occurs in the face of exceptions and so
on.

A memory leak in treefree() was plugged up --- the root node of a
function was not getting freed.

Changes since rc-1.4:

General changes:

	Some small memory leaks/uninit references revealed by Purify.

	$bqstatus for querying the exit status of a backquote.

	Globbing through unreadable directories.

	More options to whatis.

	History append which always re-opens the file (avoids
	inconsistencies over multiple NFS-mounted accesses to
	$history).

	Support "rc -s".

---------

Makefile:	Added comment referring to README for yacc/malloc problem.

uiltins.c:	Added more options to whatis, protected rlimit prototypes
		with #ifndef SYSVR4, renamed SIGCHK to sigchk.

except.c:	Patched nl_on_intr printing to happen only in interactive
		shells.

exec.c:		Added comment explaining nl_on_intr variable, renamed SIGCHK
		to sigchk.

fn.c:		Replaced by-hand consing of exception stack etc. for signal
		handler execution with call to funcall(). Replaced fun2str
		call with call on print routines.

footobar.c:	Got rid of memory leak in get_name(), parenthesize count,
		flat and var nodes for correctness in unparsing, removed
		list2str, made get_name use nalloc space, merge in a
		better parse_var from es.

glob.c:		Split out a test so that closedir is called correctly, renamed
		SIGCHK to sigchk.

glom.c:		Added bqstatus, renamed SIGCHK to sigchk, removed spurious
		setsigdefaults, patched uninit memory reference, rename
		"clear" to "memzero", wait for bq subproc to finish on EINTR.

hash.c:		Added options to function/variable print code.

history/history.c: Added '@' to the list of chars which can precede an
		ignored '-'.

input.c:	Got rid of tiny memory leak in closefds, got rid of uninit
		memory reference in popinput, moved nul ignored check into
		realgchar(), changed history append to always reopen the
		history file, replaced SIGCHK with sigchk. Freed memory
		returned by call to readline().

lex.c:		Corrected typo in comment, moved nul character ignore code
		to input routines.

main.c:		Added -s flag.

nalloc.c:	Added convenience feature to erealloc. (Allow NULL parameter)

print.c:	Changed use of va_start so broken compilers can compile
		print code.

proto.h:	Added fake memset.

rc.h:		Replaced clear() function prototype with a macro call on
		memset(), removed SIGCHK, fixed prototypes.

signal.c:	Removed unconditional exit in catcher code, renamed SIGCHK
		to sigchk.

status.c:	Rewrite sgetstatus breaking out strstatus so that bqstatus
		can be set from glom routines.

utils.c:	Got rid of clear() (use memset from C library), rename SIGCHK
		to sigchk.

var.c:	 	Got rid of memory leak in listassign(), converted list2str()
		call to something using the print routines.

version.c:	New version string.

wait.c:		Got rid of memory leak in rc_fork, renamed SIGCHK to sigchk.

walk.c:		Fixed pre-redirection bug, removed spurious setsigdefaults(),
		renamed SIGCHK to sigchk.


Changes since rc-1.5beta1

  Configuration: rc now uses GNU autoconf.

  Portability: mksignal works on HPUX 10.

  Portability: resources can be (quad_t).

  Bug: if rc was started with SIGCLD == SIG_IGN (e.g. by Solaris's
  rshd) it would loop.  Fixed by resetting SIGCLD to SIG_DFL if it
  was SIG_IGN when rc was started.

  Portability: POSIXish systems don't have NGROUPS.

Changes since rc-1.5b2

  Configuration: rc now uses GNU automake.

  Portability: use sigsetjmp() when available.

  Portability: improve tests for quad_t.

  Configuration: don't leave FIFOs in /tmp when configuring.

  Configuration: let configure find `-ltermcap' when using readline.

  Configuration: pick up default path from config.cache.

  Bug: sense of most HAVE_RESTARTABLE_SYSCALLS tests was wrong.

  Bug: print prompts with `-i', even with editline / readline.

  Testing: just say `false' (not `/bin/false').

  Bug: confusion over gid_t versus GETGROUPS_T in which.c.

  Feature: `-V' option added to report version number.

  Configuration: remove version.c; `id' is defined in main.c now.

  Bug: clear list of living children after fork(); `{ ls & wait } |cat'
  no longer hangs or panics.

  Testing: add regression test for above.

  Tidiness: all the system call wrappers to prevent calls being
  restarted now live in system-bsd.c.  The configure script decides
  whether to build system.c or system-bsd.c.  Also, signal.c is more
  careful to only declare slowbuf if it will be needed.

  Tidiness: similarly, configure decides whether to build execve.c or
  not.

  Portability: test for ssize_t and use it where available; use long if
  there's no ssize_t.

  Portability: use sigsetjmp where it's available and appropriate.  If
  no sigsetjmp, just use sigjmp; this probably fails in a traditional
  SysV environment.

  Portability: test explicitly for SysV SIGCLD semantics.  Main (and
  dubious) benefit is that you can now define a function called `sigcld'
  on systems where there is no signal called SIGCLD!

  Bug: rc has its own memory allocator; don't use malloc directly.

  Bug: the rc_wait() wrapper is only needed on systems which restart
  system calls.  On Linux, in particular, the wrapper leads to a race
  which causes rc to hang (or panic in later versions).  Other systems
  apparently don't exercise this race.

  Bug: waitforall() must return if rc_wait4() returns with errno ==
  EINTR.  Otherwise, the rc builtin `wait' cannot be interrupted if
  there are background processes (although apparently only if there is a
  handler for SIGINT).

  Portability: dreadful hack to track down the real locations of
  signal.h to find signal names. rc now builds under CygWin32!

  Portability: replace above dreadful hack with mksignal.c, contributed
  by Vincent Broman.

  Portability: use POSIX wait() macros (WIFEXITED and friends).
  Unfortunately, POSIX omitted to supply WIFDUMPED, so this doesn't buy
  a great deal.

  Distribution: remove the dependencies of y.tab.[ch] on parse.y from
  Makefile.am.  The justification for this is that, unless you're
  hacking on rc's grammar, there's no reason to use anything other
  than the distributed files (which were generated with byacc and very
  lightly edited to silence a few gcc warnings).

  Enhancement: the example in addon.c wasn't very useful, since it
  depended on files which weren't included with the distribution.  There
  is now a working, if trivial, example.

  Tidiness: the code was compiled with as many gcc warnings enabled as
  I could find.  Very few problems turned up.  Some unused function
  arguments were removed.  Where unused arguments could not be removed
  (because the function is one of a set that must all have the same
  prototype), they were renamed to `ignore'.

  Portability: some versions of readline define the name `Function',
  which rc also uses.  Its use in rc has been renamed to `rc_Function'.

  Documentation: the `history' man page didn't explain what end of line
  does in editing mode.  It now does.

  Bug: the interaction with readline was broken, particularly with
  respect to signal handling.  I've incorporated some changes from Tom
  Culliton which should sort this out.  Unfortunately, we now have 3
  different code paths for readline 2.1, readline 2.2, and editline :-(.

  Configuration: if you say `--with-readline' or `--with-editline' it is
  now an error if the appropriate library is not found.

  Bug: rc didn't work on RedHat 5 systems.  This is because of
  peculiarities in the handling of signals and system calls on this
  system (the C library attempts to fake restartable system calls).
  The fix involves testing at configure time for sigaction() and
  SA_INTERRUPT: if both exist, we set up sys_signal() to be an "always
  interrupt" wrapper around sigaction().  (If we don't have sigaction(),
  we use signal() and check for restartable system calls as usual.)

  Portability: on AIX, lconv is defined by the system header files.
  Rename lconv in print.c to avoid the clash.

  Testing: add a test that `cd' prints the new directory if we are
  interactive and the directory was found via $cdpath.

1998-07-23

  Testing: fix silly typo in above test.

  Configuration: `--with-vrl' added to support Gert-Jan Vons's readline
  library.

1998-07-24

  Portability: the autoconf macro AC_FUNC_SETPGRP doesn't work on OSF1: that
  system supports arguments to setpgrp(), but also has a prototype in
  <unistd.h> to say that it is void.  Fix this by defining our own
  RC_FUNC_SETPGRP for now.

  Bug: <sys/wait.h> was included twice in some source files.

  Configuration: automake wants `make distclean' to remove *.tab.c.
  Rename y.tab.[ch] to parse.[ch] to avoid this.

1998-07-27

  Portability: on Ultrix, `make trip' fails with `malloc: Invalid
  argument'.  Problem is that getgroups(0, NULL) in which.c returns -1.
  Add new configure test to check for POSIX getgroups() and fall back to
  NGROUPS if it's not available.  The magic is done by "getgroups.h".

  Tidiness: extract <sys/wait.h> magic into "wait.h".

1998-10-20

  Tidiness: include prototype for add_history() when doing editline.

  Documentation: document the `-V' flag and mention Linux's
  /proc/self/fd as alternative to /dev/fd.

1998-10-21

  Bug: shells need to be prepared for bogus applications to have set
  their input file descriptor to non-blocking, and set it back.

  Tidiness: <sys/types.h> is in "proto.h", so nothing else needs to
  include it explicitly.

  Documentation: document the ^A bug.

1998-10-22

  Tidiness: makenonblock() was a rather poor choice of name for
  a function which makes a file descriptor *not* nonblocking :-).

1998-10-26

  Portability: apparently some systems declare `char *basename(const
  char *)' in system header files.  Changing our basename() (in
  history.c) to match this prototype allows it to be compiled on such
  systems, and is harmless.  (Harmless, that is, if no system declares
  `char *basename(char *)'.)

1998-10-28

  Bug: system-bsd.c needs to include "wait.h".

  Warnings: some versions of gcc warn about "ambiguous" `else' clauses.

  Portability: assigning va_list objects doesn't work everywhere (Linux
  on the PowerPC, specifically).  Use the C 9x invention va_copy()
  instead, if it exists, otherwise fall back to assignment.

  Documentation: help HP-UX users by mentioning that you need `cc -Ae'.
  Also, HP-UX make will build rc in a separate directory.

  Tidiness: remove unused functions from print.c.  Anybody wanting to
  use this library in another project should follow the pointer in the
  documentation to an improved version.

1998-10-29

  Bug: the "null character ignored" warning was printed with the wrong
  line number.  Fix by adding an offset argument to pr_error.

  Portability: work around readline's broken treatment of a non-blocking
  input file descriptor.

  Testing: add `testing' auxiliary program; use `testing' to generate
  null character on the fly (since it's a nuisance having a literal
  null character in trip.rc); reset sigexit in `fn fail'; add test for
  nonblocking input file descriptor; fix test for cdpath.

  Portability: include <sys/types.h> before <sys/stat.h>.

1998-10-30

  Portability: rename basename() to rc_basename(), since the former is
  quite widespread, and has a variety of different definitions (none of
  them, of course, static).

  Portability: work around i386 GCC 2.7.2.3 optimization bug triggered
  by a (really quite simple) expression in history.c.

1998-12-04

  Bug: a debugging statement was left in history.c by mistake.

  Bug: `history' needs to check for `me' character preceded by `/', as
  well as all the other options.  An invocation like ../rc-1.5/- no
  longer loops.

  Documentation: it seems better to have but a single URL in the README
  file, which indirects to the other places of interest.

1998-12-08

  Portability: use AM_PROG_CC_STDC.  This obviates the need for a
  special hack on HP-UX.

  Documentation: document all the flags to `whatis'.

1998-12-09

  Tidiness: latest autoconf version has fixed AC_FUNC_SETPGRP, so we
  no longer need to supply our own.

  Portability: test for va_copy() needs to include <stdarg.h>.

1998-12-10

  Tidiness: move most of the configure.in nastiness into acinclude.m4.

1998-12-11

  Tidiness: the release date now only needs to be changed in one place.

1999-01-05

  Documentation: the Bell Labs rc now has the list flattening operator,
  but spelt $"foo.

1999-01-11

  Release: rc-1.5b4.

1999-01-19

  Documentation: document the `-s' option.  Also, arrange the option
  documentation in alphabetical order.

  Tidiness: just install `history' to `$(bindir)/-'; don't create an
  extra link (which `make clean' failed to remove).

1999-01-22

  Bug: `-s' should not imply `-i'.

  Testing: add regression test for `-s' behaviour.

1999-01-27

  Documentation: default path was out of date; minor consistency
  improvements.

  Release: rc-1.5b5.

1999-02-15

  Portability: AM_INIT_AUTOMAKE calls AC_ARG_PROGRAM and
  AC_PROG_INSTALL.  Don't do it explicitly.  For once, the configure
  script gets smaller!  Program name transformations work right now.

  Documentation: note that rc has no `set' builtin; fix weird variable
  name example; any character except `=' may be used in a variable name;
  document bqstatus; document rc's exit status; other tidying.

1999-03-01

  Documentation: document the yacc-imposed limit on ; separated commands
  in a line.

1999-05-06

  Portability: tgetent() might be in -lncurses instead of -ltermcap.

1999-05-10

  Portability: Linux *almost* has SysV SIGCLD semantics, and we need to
  detect them.

  Bug: if we reset SIGCLD to SIG_DFL, we need to record the fact in the
  sighandlers[] array.

1999-05-12

  Documentation: note that `$(a.b)' syntax only mostly works, and that
  list definitions in exported functions are noisier than they need to
  be.

  Release: rc-1.5b6.

1999-05-19

  Documentation: minor fixes to man page.

1999-05-26

  Tidiness: `make distclean' now removes sigmsgs.[ch].

1999-05-28

  Release: rc-1.6.

1999-08-19

  Portability: the proposed C 9x __va_copy() macro is called that, not
  va_copy(), as I thought.  Furthermore, it is defined to be a macro, so
  we don't need to use autoconf to check for it.

1999-10-11

  Bug: absolute globs don't need special case in doglob().  Avoids
  creating path names like `//tmp', which is a UNC path under CygWin.

1999-10-12

  Portability: status.c assumes traditional Unix layout of 0 and 1 exit
  statuses in the parent, which is not shared by BeOS.  Add mkstatval.c.

1999-10-13

  Bug: a read(2) error in fdgchar() should call rc_raise(), not
  rc_exit().  This bug is easily tickled on systems (like Linux) which
  allow you to open(2) but not read(2) directories: `. /tmp'.  In all
  previous versions of rc, this caused the shell to exit.

  Portability: use POSIX strerror() where it's available; fake it with
  sys_errlist[] where not.

  Feature: replace `-V' with `version' variable.

1999-10-14

  Portability: exporting `path' causes indigestion in CygWin.  Since
  it's virtually impossible for a child `rc' process to inherit `path'
  (which I consider a bug, but it's not going to be fixed now), simply
  don't export `path'.

  Portability: add /usr/bsd to default default path.

  Documentation: failing to search $path for a `.' command is at least
  an incompatibility with Tenth Edition rc, and probably a bug.

1999-11-10

  Feature: make `version' a list.

1999-11-11

  Documentation: when running configure, you need to set LDFLAGS for
  `-L' options, not LIBS.

  Release: rc-1.6b1.

1999-12-10

  Bug: absolute globs do still need a special case.  `/*' works again now, but
  we still avoid creating names like `//tmp/foo'.

  Bug: avoid a putative race condition in signal.c.

  Documentation: extra parentheses around `~' and `!' expressions are
  forbidden.  Tom Duff's paper is not distributed with rc, but is
  available on the web.

  Release: rc-1.6b2.

2000-04-19

  Bug: isatty() tests in input.c are relevant to any fd, not just 0.
  Now `. -i /dev/tty' works right.

  Bug: fn sigexit wasn't always cleared in child shells.

  Bug: `~ () '*'' dumped core.

2000-05-25

  Portability: need special runes for read() returning EIO under job
  control systems.

2000-06-20

  Feature: add `-I' flag (definitively not interactive) for
  compatibility with Plan 9 rc.

2000-11-27

  Portability: configure fails to detect strerror() on NetBSD; we need
  to include <string.h>.

2001-06-18

  Bug: you can't pass a short to a stdargs function!

2001-09-27

  Documentation: we don't consider that `.' failing to search path is
  a bug.

  Feature: ^A in lists is now handled transparently.

2001-10-01

  Bug: it's no longer possible to use parentheses to sneak a word that
  needs quoting past the "quoting detector", so `fn x { echo $(x.y) }'
  now works both in the current rc and its descendants.

  Documentation: mention the catastrophic effects of a semantic error
  in fn prompt.

2001-10-03

  Feature: exported lists no longer use redundant parentheses.

2001-10-04

  Bug: semantic errors in `fn prompt' no longer throw rc into a tailspin.

  Feature: don't export $cdpath or $home (the lower-case versions).

2001-10-12

  Release: rc-1.6b3.

2001-10-25

  Feature: large file support (thanks Scott Schwartz, Chris
  Siebenmann).

2001-10-29

  Bug: space vs tab confusion in commented out Makefile rules to
  rebuild parser (thanks Gary Carvell).

2001-10-31

  Documentation: subscripted variables don't work in here documents.

  Release: rc-1.6c4.

2001-11-01

  Bug: more wrongly ordered header file includes (thanks Callum
  Gibson).

2001-11-06

  Portability: rename print.c::utoa() to rc_utoa() to avoid QNX name
  clash; use "sh -c 'test ...'" in trip.rc for missing standalone
  `test' on QNX (thanks Stefan Dalibor).

2001-11-20

  Documentation: tighten up various descriptions, and include some
  more examples.

  Release: rc-1.6c5.

2001-11-23

  Bug: parselimit() was broken in various ways (thanks Chris
  Siebenmann).

2002-02-08

  Bug: yet more wrongly ordered header file includes.

  Release: rc-1.6c6.

2002-04-03

  Feature: make $version less magical, and exportable if it's changed
  from its default value.  Same for $prompt (thank Erik Quanstrom).

  Bug: make $bqstatus and $status not exportable.

  Feature: "stuttering" colons for multiple replacements in the
  history programs (thanks Callum Gibson).

2002-05-22

  Documentation: possible warning in tripping.c (thanks Dan Moniz).

  Release: rc-1.6c7.

2002-06-18

  Release: rc-1.7.

2002-07-25

  Bug: fix globbing of broken symlinks.

2002-07-31

  Bug: readline doesn't handle EIO either.

2002-08-15

  Bug: variables that are sometimes exported (i.e. $prompt and
  $version) need to be made exportable if they are inherited from the
  environment.

  Portability: don't call sigaction() for SIGKILL or SIGSTOP; don't
  hand a garbage signal mask to sigaction() (thanks Jeremy
  Fitzhardinge).  Also, remove use of SA_INTERRUPT (SUSv3, BSD,
  etc. have SA_RESTART with the inverted meaning).

2002-08-20

  Bug: don't call ealloc(0) on systems where getgroups() doesn't
  return egid (thanks Chris Siebenmann).

2002-11-27

  Bug: history dumps core if more colons than substitutions (thanks
  Callum Gibson); history fails to avoid itself if it's the only
  command; history writes and reads outside allocated memory.

  Configuration: upgrade to autoconf-2.56 and automake-1.7.1.

2003-07-17

  Testing: remove test for large file support, as it causes
  indigestion on file systems that don't support sparse files (thanks
  Scott Schwartz).

2003-07-22

  Release: rc-1.7.1.

2003-09-24

  Tidiness: minor improvements to input.c.

2014-02-26

  Bug: fix for CVE-2014-1936 from Jakub Wilk.

2014-06-29

  Documentation: update email and web addresses.

2014-08-31

  Feature: support quoting for filename completion in GNU readline.

2014-09-01

  Bug: quoting of glob characters was broken (thanks Leah Neukirchen);
  fix the "sneaky parens" bug properly (thanks Wolfgang Zekoll).

  Feature: allow $"x as a synonym for $^x

  Release: rc-1.7.2.

2015-04-03

  Packaging: the rc.spec file was very out-of-date.

2015-04-04

  Portability: the comment from 1999-08-19 may well have been true at
  the time, but the final version of the C99 standard called varargs
  copying macro va_copy().

2015-04-07

  Portability: look in -ltinfo for tgetent.

  Packaging: various autoconf / automake updates and tweaks.

2015-04-14

  Bug: in initinput(), the call ugchar(EOF) used the ungetcount member
  of the top Input structure without initializing it. Thanks to Jeff
  Johnson for finding this, Robert Scheck for reporting it, and Uli
  Drepper for implementing MALLOC_PERTURB_, a cheap way to find uses of
  uninitialized memory.

2015-04-18

  Licensing: tweaked to match exactly the "zlib with acknowledgement"
  license which is used by nunit and is already approved by various
  distros.

2015-04-20

  Release: rc-1.7.3.

2015-05-12

  Licensing: due to GPL compatibility concerns, the license is changed
  again to the "zlib" license. (N.B. This license change was agreed and
  approved by Byron Rakitzis, who is the copyright holder.)

  Testing: swap arguments to mktemp to be kinder to NetBSD (thanks Piotr
  Meyer).

2015-05-13

  Release: rc-1.7.4.

2015-06-24

  Portability: eschew GNU-specific "date -I" (thanks Ross Lonstein;
  github #4).

2015-10-26

  Bug: fix use-after-free bug (thanks Dražen Borković; github #9 and
  #13).

2015-11-28

  Bug: fix bug with signal handlers and readline (thanks Bert Münnich).

2016-02-26

  Bug: fix bug with "break" inside local variable block (thanks Dražen
  Borković and Bert Münnich; github #11 and #21).

2016-08-25

  Bug: more signal / readline fixes (thanks Bert Münnich; github #14).

2016-08-27

  Portability: replace reldate with "git describe" (thanks @RamKromberg).

  Documentation: "~ $x ()" is something of a special case. The man page
  now goes into some more detail.

2017-02-27

  Feature: parse equals like a keyword, meaning it can appear unquoted in
  commands. For example, rather than having to write

    ls --color'='tty # or ls '--color=tty' or similar

  one may now write simply

    ls --color=tty

  Special thanks to Bert Münnich for fixing this major irritation
  (github #29).

2017-05-11

  Bug: the "-e" flag did the wrong thing with respect to "while" loops (thanks
  Dražen Borković; github #34 and #35).

2017-06-23

  Feature: new developer mode, enabled with "--enable-develop" at the
  "configure" stage, dumps each parse tree after it is built.

  Bug: the precedence of prefix redirect was lower than pipe, which led to
  some counter-intuitive parses (thanks Casper Ti. Vector; github #33).

  Bug: rc with readline support failed to notice window size changes correctly
  (thanks Chris Siebenmann; github #32).

2017-08-25

  Testing: use "pwd -P" which is friendlier to macOS (thanks Dražen Borković;
  github #36).

2017-08-25

  Feature: add a "continue" builtin (thanks Casper Ti. Vector and Dražen
  Borković; github #25 and #37).

2017-10-27

  Bug: using "-e" led to incorrect exit status (thanks @hallik and Bert
  Münnich).

  Portability: burning the build date into the binary makes a
  reproducible build impossible. Replace it with the git description
  (thanks @RamKromberg; github #26).

2018-02-17

  Portability: remove all references to SIGCLD (thanks Leah Neukirchen).

2018-03-05

  Bug: the grammar disallowed local assignments and redirections in the true
  branch of `if` when there was an `else` clause (thanks Dražen Borković and
  Bert Münnich; github #31).

2018-03-17

  Feature: implement the `flag` builtin (github #20).

2018-03-19

  Feature: implement `if not` (github #19).

  Feature: default values for $nl and $tab (github #43).

2018-03-20

  Tidiness: be consistent about using tabs everywhere, and add a .vimrc to
  keep it so in the future.

2018-05-30

  Feature: readline can now complete commands (thanks Bert Münnich; github
  #2).