NEWS

   1 This is a terse description of the new features added to bash-2.02 since
   2 the release of bash-2.01.1.  As always, the manual page (doc/bash.1) is
   3 the place to look for complete descriptions.
   4
   5 1. New Features in Bash
   6
   7 a.  A new version of malloc, based on the older GNU malloc, that has many
   8     changes, is more page-based, is more conservative with memory usage,
   9     and does not `orphan' large blocks when they are freed.
  10
  11 b.  A new version of gmalloc, based on the old GLIBC malloc, with many
  12     changes and range checking included by default.
  13
  14 c.  A new implementation of fnmatch(3) that includes full POSIX.2 Basic
  15     Regular Expression matching, including character classes, collating
  16     symbols, equivalence classes, and support for case-insensitive pattern
  17     matching.
  18
  19 d.  ksh-88 egrep-style extended pattern matching ([@+*?!](patlist)) has been
  20     implemented, controlled by a new `shopt' option, `extglob'.
  21
  22 e.  There is a new ksh-like `[[' compound command, which implements
  23     extended `test' functionality.
  24
  25 f.  There is a new `printf' builtin, implemented according to the POSIX.2
  26     specification.
  27
  28 g.  There is a new feature for command substitution: $(< filename) now expands
  29     to the contents of `filename', with any trailing newlines removed
  30     (equivalent to $(cat filename)).
  31
  32 h.  There are new tilde prefixes which expand to directories from the
  33     directory stack.
  34
  35 i.  There is a new `**' arithmetic operator to do exponentiation.
  36
  37 j.  There are new configuration options to control how bash is linked:
  38     `--enable-profiling', to allow bash to be profiled with gprof, and
  39     `--enable-static-link', to allow bash to be linked statically.
  40
  41 k.  There is a new configuration option, `--enable-cond-command', which
  42     controls whether or not the `[[' command is included.  It is on by
  43     default.
  44
  45 l.  There is a new configuration option, `--enable-extended-glob', which
  46     controls whether or not the ksh extended globbing feature is included.
  47     It is enabled by default.
  48
  49 m.  There is a new configuration #define in config.h.top that, when enabled,
  50     will cause all login shells to source /etc/profile and one of the user-
  51     specific login shell startup files, whether or not the shell is
  52     interactive.
  53
  54 n.  There is a new invocation option, `--dump-po-strings', to dump
  55     a shell script's translatable strings ($"...") in GNU `po' format.
  56
  57 o.  There is a new `shopt' option, `nocaseglob', to enable case-insensitive
  58     pattern matching when globbing filenames and using the `case' construct.
  59
  60 p.  There is a new `shopt' option, `huponexit', which, when enabled, causes
  61     the shell to send SIGHUP to all jobs when an interactive login shell
  62     exits.
  63
  64 q.  `bind' has a new `-u' option, which takes a readline function name as an
  65     argument and unbinds all key sequences bound to that function in a
  66     specified keymap.
  67
  68 r.  `disown' now has `-a' and `-r' options, to limit operation to all jobs
  69     and running jobs, respectively.
  70
  71 s.  The `shopt' `-p' option now causes output to be displayed in a reusable
  72     format.
  73
  74 t.  `test' has a new `-N' option, which returns true if the filename argument
  75     has been modified since it was last accessed.
  76
  77 u.  `umask' now has a `-p' option to print output in a reusable format.
  78
  79 v.  A new escape sequence, `\xNNN', has been added to the `echo -e' and $'...'
  80     translation code.  It expands to the character whose ascii code is NNN
  81     in hexadecimal.
  82
  83 w.  The prompt string expansion code has a new `\r' escape sequence.
  84
  85 x.  The shell may now be cross-compiled for the CYGWIN32 environment on
  86     a Unix machine.
  87
  88 2. New Features in Readline
  89
  90 a.  There is now an option for `iterative' yank-last-arg handline, so a user
  91     can keep entering `M-.', yanking the last argument of successive history
  92     lines.
  93
  94 b.  New variable, `print-completions-horizontally', which causes completion
  95     matches to be displayed across the screen (like `ls -x') rather than up
  96     and down the screen (like `ls').
  97
  98 c.  New variable, `completion-ignore-case', which causes filename completion
  99     and matching to be performed case-insensitively.
 100
 101 d.  There is a new bindable command, `magic-space', which causes history
 102     expansion to be performed on the current readline buffer and a space to
 103     be inserted into the result.
 104
 105 e.  There is a new bindable command, `menu-complete', which enables tcsh-like
 106     menu completion (successive executions of menu-complete insert a single
 107     completion match, cycling through the list of possible completions).
 108
 109 f.  There is a new bindable command, `paste-from-clipboard', for use on Win32
 110     systems, to insert the text from the Win32 clipboard into the editing
 111     buffer.
 112
 113 g.  The key sequence translation code now understands printf-style backslash
 114     escape sequences, including \NNN octal escapes.  These escape sequences
 115     may be used in key sequence definitions or macro values.
 116
 117 h.  An `$include' inputrc file parser directive has been added.
 118
 119 -------------------------------------------------------------------------------
 120 This is a terse description of the new features added to bash-2.01 since
 121 the release of bash-2.0.  As always, the manual page (doc/bash.1) is the
 122 place to look for complete descriptions.
 123
 124 1. New Features in Bash
 125
 126 a.  There is a new builtin array variable: GROUPS, the set of groups to which
 127     the user belongs.  This is used by the test suite.
 128
 129 2.  New Features in Readline
 130
 131 a.  If a key sequence bound to `universal-argument' is read while reading a
 132     numeric argument started with `universal-argument', it terminates the
 133     argument but is otherwise ignored.  This provides a way to insert multiple
 134     instances of a digit string, and is how GNU emacs does it.
 135
 136 -------------------------------------------------------------------------------
 137 This is a terse description of the new features added to bash-2.0 since
 138 the release of bash-1.14.7.  As always, the manual page (doc/bash.1) is
 139 the place to look for complete descriptions.
 140
 141 1.  New Features in Bash
 142
 143 a.  There is a new invocation option, -D, that dumps translatable strings
 144     in a script.
 145
 146 b.  The `long' invocation options must now be prefixed with `--'.
 147
 148 c.  New long invocation options:  --dump-strings, --help, --verbose
 149
 150 d.  The `nolineediting' invocation option was renamed to `noediting'.
 151
 152 e.  The `nobraceexpansion' and `quiet' long invocation options were removed.
 153
 154 f.  The `--help' and `--version' long options now work as the GNU coding
 155     standards specify.
 156
 157 g.  If invoked as `sh', bash now enters posix mode after reading the
 158     startup files, and reads and executes commands from the file named
 159     by $ENV if interactive (as POSIX.2 specifies).  A login shell invoked
 160     as `sh' reads $ENV after /etc/profile and ~/.profile.
 161
 162 h.  There is a new reserved word, `time', for timing pipelines, builtin
 163     commands, and shell functions.  It uses the value of the TIMEFORMAT
 164     variable as a format string describing how to print the timing
 165     statistics.
 166
 167 i.  The $'...' quoting syntax expands ANSI-C escapes in ... and leaves the
 168     result single-quoted.
 169
 170 j.  The $"..." quoting syntax performs locale-specific translation of ...
 171     and leaves the result double-quoted.
 172
 173 k.  LINENO now works correctly in functions.
 174
 175 l.  New variables: DIRSTACK, PIPESTATUS, BASH_VERSINFO, HOSTNAME, SHELLOPTS,
 176     MACHTYPE.  The first three are array variables.
 177
 178 m.  The BASH_VERSION and BASH_VERSINFO variables now include the shell's
 179     `release status' (alpha[N], beta[N], release).
 180
 181 n.  Some variables have been removed:  MAIL_WARNING, notify, history_control,
 182     command_oriented_history, glob_dot_filenames, allow_null_glob_expansion,
 183     nolinks, hostname_completion_file, noclobber, no_exit_on_failed_exec, and
 184     cdable_vars.  Most of them are now implemented with the new `shopt'
 185     builtin; others were already implemented by `set'.
 186
 187 o.  Bash now uses some new variables:  LC_ALL, LC_MESSAGES, LC_CTYPE,
 188     LC_COLLATE, LANG, GLOBIGNORE, HISTIGNORE.
 189
 190 p.  The shell now supports integer-indexed arrays of unlimited length,
 191     with a new compound assignment syntax and changes to the appropriate
 192     builtin commands (declare/typeset, read, readonly, etc.).  The array
 193     index may be an arithmetic expression.
 194
 195 q.  ${!var}: indirect variable expansion, equivalent to eval \${$var}.
 196
 197 r.  ${paramter:offset[:length]}: variable substring extraction.
 198
 199 s.  ${parameter/pattern[/[/]string]}: variable pattern substitution.
 200
 201 t.  The $[...] arithmetic expansion syntax is no longer supported, in
 202     favor of $((...)).
 203
 204 u.  Aliases can now be expanded in shell scripts with a shell option
 205     (shopt expand_aliases).
 206
 207 v.  History and history expansion can now be used in scripts with
 208     set -o history and set -H.
 209
 210 w.  All builtins now return an exit status of 2 for incorrect usage.
 211
 212 x.  Interactive shells resend SIGHUP to all running or stopped children
 213     if (and only if) they exit due to a SIGHUP.
 214
 215 y.  New prompting expansions: \a, \e, \H, \T, \@, \v, \V.
 216
 217 z.  Variable expansion in prompt strings is now controllable via a shell
 218     option (shopt promptvars).
 219
 220 aa. Bash now defaults to using command-oriented history.
 221
 222 bb. The history file ($HISTFILE) is now truncated to $HISTFILESIZE after
 223     being written.
 224
 225 cc. The POSIX.2 conditional arithmetic evaluation syntax (expr ? expr : expr)
 226     has been implemented.
 227
 228 dd. Each builtin now accepts `--' to signify the end of the options, except
 229     as documented (echo, etc.).
 230
 231 ee. All builtins use -p to display values in a re-readable format where
 232     appropriate, except as documented (echo, type, etc.).
 233
 234 ff. The `alias' builtin has a new -p option.
 235
 236 gg. Changes to the `bind' builtin:
 237         o has new options: -psPSVr.
 238         o the `-d' option was renamed to `-p'
 239         o the `-v' option now dumps variables; the old `-v' is now `-P'
 240
 241 hh. The `bye' synonym for `exit' was removed.
 242
 243 ii. The -L and -P options to `cd' and `pwd' have been documented.
 244
 245 jj. The `cd' builtin now does spelling correction on the directory name
 246     by default.  This is settable with a shell option (shopt cdspell).
 247
 248 kk. The `declare' builtin has new options: -a, -F, -p.
 249
 250 ll. The `dirs' builtin has new options: -c, -p, -v.
 251
 252 mm. The new `disown' builtin removes jobs from the shell's jobs table
 253     or inhibits the resending of SIGHUP when the shell receives a
 254     SIGHUP.
 255
 256 nn. The `echo' builtin has a new escape character: \e.
 257
 258 oo. The `enable' builtin can now load new builtins dynamically from shared
 259     objects on systems with the dlopen/dlsym interface.  There are a number
 260     of examples in the examples/loadables directory.  There are also
 261     new options: -d, -f, -s, -p.
 262
 263 pp. The `-all' option to `enable' was removed in favor of `-a'.
 264
 265 qq. The `exec' builtin has new options: -l, -c, -a.
 266
 267 rr. The `hash' builtin has a new option: -p.
 268
 269 ss. The `history' builtin has new options: -c, -p, -s.
 270
 271 tt. The `jobs' builtin has new options: -r, -s.
 272
 273 uu. The `kill' builtin has new options: -n signum, -l signame.
 274
 275 vv. The `pushd' and `popd' builtins have a new option: -n.
 276
 277 ww. The `read' builtin has new options: -p prompt, -e, -a.
 278
 279 xx. The `readonly' builtin has a new -a option, and the -n option was removed.
 280
 281 yy. Changes to the `set' builtin:
 282         o new options: -B, -o keyword, -o onecmd, -o history
 283         o options removed: -l, -d, -o nohash
 284         o options changed: +o, -h, -o hashall
 285         o now displays variables in a format that can be re-read as input
 286
 287 zz. The new `shopt' builtin controls shell optional behavior previously
 288     done by setting and unsetting certain shell variables.
 289
 290 aaa. The `test' builtin has new operators: -o option, s1 == s2, s1 < s2,
 291      and s1 > s2, where s1 and s2 are strings.
 292
 293 bbb. There is a new trap, DEBUG, executed after every simple command.
 294
 295 ccc. The `trap' builtin has a new -p option.
 296
 297 ddd. The `ulimit' builtin has a new -l option on 4.4BSD-based systems.
 298
 299 eee. The PS1, PS2, PATH, and IFS variables may now be unset.
 300
 301 fff. The restricted shell mode has been expanded and is now documented.
 302
 303 ggg. Security improvements:
 304         o functions are not imported from the environment if running setuid
 305           or with -p
 306         o no startup files are sourced if running setuid or with -p
 307
 308 hhh. The documentation has been overhauled:  the texinfo manual was
 309      expanded, and HTML versions of the man page and texinfo manual
 310      are included.
 311
 312 iii. Changes to Posix mode:
 313         o Command lookup now finds special builtins before shell functions.
 314         o Failure of a special builtin causes a non-interactive shell to
 315           exit.  Failures are defined in the POSIX.2 specification.
 316         o If the `cd' builtin finds a directory to change to using $CDPATH,
 317           the value assigned to PWD when `cd' completes does not contain
 318           any symbolic links.
 319         o A non-interactive shell exits if a variable assignment error
 320           occurs when no command name follows the assignment statements.
 321         o A non-interactive shell exits if the interation variable in a
 322           `for' statement or the selection variable in a `select' statement
 323           is read-only or another variable assignment error occurs.
 324         o The `<>' redirection operator now opens a file for both stdin and
 325           stdout by default, not just when in posix mode.
 326         o Assignment statements preceding special builtins now persist in
 327           the shell's environment when the builtin completes.
 328
 329      Posix mode is now completely POSIX.2-compliant (modulo bugs).  When
 330      invoked as sh, bash should be completely POSIX.2-compliant.
 331
 332 jjj. The default value of PS1 is now "\s-\v\$ ".
 333
 334 kkk. The ksh-like ((...)) arithmetic command syntax has been implemented.
 335      This is exactly equivalent to `let "..."'.
 336
 337 lll. Integer constants have been extended to base 64.
 338
 339 mmm. The `ulimit' builtin now sets both hard and soft limits and reports the
 340      soft limit by default.
 341
 342 2.  New Features in Readline
 343
 344 a.  New variables:  enable-keypad, input-meta (new name for meta-flag),
 345     mark-directories, visible-stats (now documented), disable-completion,
 346     comment-begin.
 347
 348 b.  New bindable commands:  kill-region, copy-region-as-kill,
 349     copy-backward-word, copy-forward-word, set-mark, exchange-point-and-mark,
 350     character-search, character-search-backward, insert-comment,
 351     glob-expand-word, glob-list-expansions, dump-variables, dump-macros.
 352
 353 c.  New emacs keybindings:  delete-horizontal-space (M-\),
 354     insert-completions (M-*), possible-completions (M-=).
 355
 356 d.  The history-search-backward and history-search-forward commands were
 357     modified to be the same as previous-line and next-line if point is at
 358     the start of the line.
 359
 360 e.  More file types are available for the visible-stats mode.
 361
 362 3.  Changes of interest in the Bash implementation
 363
 364 a.  There is a new autoconf-based configuration mechanism.
 365
 366 b.  More things have been moved from Posix mode to standard shell behavior.
 367
 368 c.  The trace output (set -x) now inserts quotes where necessary so it can
 369     be reused as input.
 370
 371 d.  There is a compile-time option for a system-wide interactive shell
 372     startup file (disabled by default).
 373
 374 e.  The YACC grammar is smaller and tighter, and all 66 shift-reduce
 375     conflicts are gone.  Several parsing bugs have been fixed.
 376
 377 f.  Builtin option parsing has been regularized (using internal_getopt()),
 378     with the exception of `echo', `type', and `set'.
 379
 380 g.  Builtins now return standard usage messages constructed from the
 381     `short doc' used by the help builtin.
 382
 383 h.  Completion now quotes using backslashes by default, but honors
 384     user-supplied quotes.
 385
 386 i.  The GNU libc malloc is available as a configure-time option.
 387
 388 j.  There are more internationalization features; bash uses gettext if
 389     it is available.  The $"..." translation syntax uses the current
 390     locale and gettext.
 391
 392 k.  There is better reporting of job termination when the shell is not
 393     interactive.
 394
 395 l.  The shell is somewhat more efficient: it uses a little less memory and
 396     makes fewer system calls.
 397
 398 4.  Changes of interest in the Readline implementation
 399
 400 a.  There is now support for readline `callback' functions.
 401
 402 b.  There is now support for user-supplied input, redisplay, and terminal
 403     preparation functions.
 404
 405 c.  Most of the shell-specific code in readline has been generalized or
 406     removed.
 407
 408 d.  Most of the annoying redisplay bugs have been fixed, notably the problems
 409     with incremental search and excessive redrawing when special characters
 410     appear in the prompt string.
 411
 412 e.  There are new library functions and variables available to application
 413     writers, most having to do with completion and quoting.
 414
 415 f.  The NEWLINE character (^J) is now treated as a search terminator by the
 416     incremental search functions.