new `patsub_replacement' shell option

CWRU/CWRU.chlog

@@ -2324,3 +2324,13 @@ doc/{bash.1,bashref.texi}
 	  and the shell receives a SIGINT while waiting for the foreground
 	  command to complete. Added at Red Hat's request. A complete
 	  discussion is at https://www.cons.org/cracauer/sigint.html
+
+				   10/25
+				   -----
+builtins/shopt.def
+	- patsub_replacement: new shell option, exposes patsub_replacement
+	  variable controlling whether pattern substitution expands `&' in
+	  the replacement string. Still enabled by default.
+
+doc/{bash.1,bashref.texi}
+	- patsub_replacement: document new shopt option

builtins/shopt.def

@@ -95,6 +95,7 @@ extern int localvar_inherit;
 extern int localvar_unset;
 extern int varassign_redir_autoclose;
 extern int singlequote_translations;
+extern int patsub_replacement;
 
 #if defined (EXTENDED_GLOB)
 extern int extended_glob;
@@ -237,6 +238,7 @@ static struct {
   { "nocasematch", &match_ignore_case, (shopt_set_func_t *)NULL },
   { "noexpand_translation", &singlequote_translations, (shopt_set_func_t *)NULL },
   { "nullglob",	&allow_null_glob_expansion, (shopt_set_func_t *)NULL },
+  { "patsub_replacement", &patsub_replacement, (shopt_set_func_t *)NULL },
 #if defined (PROGRAMMABLE_COMPLETION)
   { "progcomp", &prog_completion_enabled, (shopt_set_func_t *)NULL },
 #  if defined (ALIAS)
@@ -363,6 +365,7 @@ reset_shopt_options ()
   source_uses_path = promptvars = 1;
   varassign_redir_autoclose = 0;
   singlequote_translations = 0;
+  patsub_replacement = 1;
 
 #if defined (JOB_CONTROL)
   check_jobs_at_exit = 0;

doc/bash.1

@@ -5,12 +5,12 @@
 .\"	Case Western Reserve University
 .\"	chet.ramey@case.edu
 .\"
-.\"	Last Change: Tue Oct 19 11:34:57 EDT 2021
+.\"	Last Change: Mon Oct 25 11:23:10 EDT 2021
 .\"
 .\" bash_builtins, strip all but Built-Ins section
 .if \n(zZ=1 .ig zZ
 .if \n(zY=1 .ig zY
-.TH BASH 1 "2021 October 19" "GNU Bash 5.1"
+.TH BASH 1 "2021 October 25" "GNU Bash 5.1"
 .\"
 .\" There's some problem with having a `@'
 .\" in a tagged paragraph with the BSD man macros.
@@ -3367,7 +3367,8 @@ matches of \fIpattern\fP are deleted.
 If \fIstring\fP is null,
 matches of \fIpattern\fP are deleted
 and the \fB/\fP following \fIpattern\fP may be omitted.
-Any unquoted instances of \fB&\fP in \fIstring\fP are replaced with the
+If the \fBpatsub_replacement\fP shell option is enabled using \fBshopt\fP,
+any unquoted instances of \fB&\fP in \fIstring\fP are replaced with the
 matching portion of \fIpattern\fP.
 Backslash is used to quote \fB&\fP in \fIstring\fP; the backslash is removed
 in order to permit a literal \fB&\fP in the replacement string.
@@ -10481,6 +10482,13 @@ files (see
 above)
 to expand to a null string, rather than themselves.
 .TP 8
+.B patsub_replacement
+If set, \fBbash\fP
+expands occurrences of \fB&\fP in the replacement string of pattern
+substitution to the text matched by the pattern, as described
+under \fBParameter Expansion\fP above.
+This option is enabled by default.
+.TP 8
 .B progcomp
 If set, the programmable completion facilities (see
 \fBProgrammable Completion\fP above) are enabled.

doc/bashref.info

@@ -2,9 +2,9 @@ This is bashref.info, produced by makeinfo version 6.8 from
 bashref.texi.
 
 This text is a brief description of the features that are present in the
-Bash shell (version 5.1, 15 October 2021).
+Bash shell (version 5.1, 25 October 2021).
 
-   This is Edition 5.1, last updated 15 October 2021, of 'The GNU Bash
+   This is Edition 5.1, last updated 25 October 2021, of 'The GNU Bash
 Reference Manual', for 'Bash', Version 5.1.
 
    Copyright (C) 1988-2021 Free Software Foundation, Inc.
@@ -27,10 +27,10 @@ Bash Features
 *************
 
 This text is a brief description of the features that are present in the
-Bash shell (version 5.1, 15 October 2021).  The Bash home page is
+Bash shell (version 5.1, 25 October 2021).  The Bash home page is
 <http://www.gnu.org/software/bash/>.
 
-   This is Edition 5.1, last updated 15 October 2021, of 'The GNU Bash
+   This is Edition 5.1, last updated 25 October 2021, of 'The GNU Bash
 Reference Manual', for 'Bash', Version 5.1.
 
    Bash contains features that appear in other popular shells, and some
@@ -2076,7 +2076,8 @@ omitted, the operator tests only for existence.
      of PATTERN are deleted and the '/' following PATTERN may be
      omitted.
 
-     Any unquoted instances of '&' in STRING are replaced with the
+     If the 'patsub_replacement' shell option is enabled using 'shopt',
+     any unquoted instances of '&' in STRING are replaced with the
      matching portion of PATTERN.  This is intended to duplicate a
      common 'sed' idiom.  Backslash is used to quote '&' in STRING; the
      backslash is removed in order to permit a literal '&' in the
@@ -3022,6 +3023,33 @@ the 'wait' builtin, the reception of a signal for which a trap has been
 set will cause the 'wait' builtin to return immediately with an exit
 status greater than 128, immediately after which the trap is executed.
 
+   When job control is not enabled, and Bash is waiting for a foreground
+command to complete, the shell receives keyboard-generated signals such
+as 'SIGINT' (usually generated by '^C') that users commonly intend to
+send to that command.  This happens because the shell and the command
+are in the same process group as the terminal, and '^C' sends 'SIGINT'
+to all processes in that process group.  See *note Job Control::, for a
+more in-depth discussion of process groups.
+
+   When Bash is running without job control enabled and receives
+'SIGINT' while waiting for a foreground command, it waits until that
+foreground command terminates and then decides what to do about the
+'SIGINT':
+
+  1. If the command terminates due to the 'SIGINT', Bash concludes that
+     the user meant to end the entire script, and acts on the 'SIGINT'
+     (e.g., by running a 'SIGINT' trap or exiting itself);
+
+  2. If the pipeline does not terminate due to 'SIGINT', the program
+     handled the 'SIGINT' itself and did not treat it as a fatal signal.
+     In that case, Bash does not treat 'SIGINT' as a fatal signal,
+     either, instead assuming that the 'SIGINT' was used as part of the
+     program's normal operation (e.g., 'emacs' uses it to abort editing
+     commands) or deliberately discarded.  However, Bash will run any
+     trap set on 'SIGINT', as it does with any other trapped signal it
+     receives while it is waiting for the foreground command to
+     complete, for compatibility.
+
 
 File: bashref.info,  Node: Shell Scripts,  Prev: Executing Commands,  Up: Basic Shell Features
 
@@ -4932,6 +4960,12 @@ This builtin allows you to change additional shell optional behavior.
           If set, Bash allows filename patterns which match no files to
           expand to a null string, rather than themselves.
 
+     'patsub_replacement'
+          If set, Bash expands occurrences of '&' in the replacement
+          string of pattern substitution to the text matched by the
+          pattern, as described above (*note Shell Parameter
+          Expansion::).  This option is enabled by default.
+
      'progcomp'
           If set, the programmable completion facilities (*note
           Programmable Completion::) are enabled.  This option is
@@ -12373,103 +12407,103 @@ Node: Shell Expansions69747
 Node: Brace Expansion71874
 Node: Tilde Expansion74608
 Node: Shell Parameter Expansion77229
-Node: Command Substitution95023
-Node: Arithmetic Expansion96378
-Node: Process Substitution97346
-Node: Word Splitting98466
-Node: Filename Expansion100410
-Node: Pattern Matching103010
-Node: Quote Removal107618
-Node: Redirections107913
-Node: Executing Commands117573
-Node: Simple Command Expansion118243
-Node: Command Search and Execution120353
-Node: Command Execution Environment122731
-Node: Environment125766
-Node: Exit Status127429
-Node: Signals129213
-Node: Shell Scripts131180
-Node: Shell Builtin Commands134207
-Node: Bourne Shell Builtins136245
-Node: Bash Builtins157706
-Node: Modifying Shell Behavior188523
-Node: The Set Builtin188868
-Node: The Shopt Builtin199281
-Node: Special Builtins214710
-Node: Shell Variables215689
-Node: Bourne Shell Variables216126
-Node: Bash Variables218230
-Node: Bash Features251045
-Node: Invoking Bash252058
-Node: Bash Startup Files258071
-Node: Interactive Shells263174
-Node: What is an Interactive Shell?263584
-Node: Is this Shell Interactive?264233
-Node: Interactive Shell Behavior265048
-Node: Bash Conditional Expressions268561
-Node: Shell Arithmetic273203
-Node: Aliases276147
-Node: Arrays278760
-Node: The Directory Stack284769
-Node: Directory Stack Builtins285553
-Node: Controlling the Prompt289813
-Node: The Restricted Shell292778
-Node: Bash POSIX Mode295375
-Node: Shell Compatibility Mode306648
-Node: Job Control313304
-Node: Job Control Basics313764
-Node: Job Control Builtins318766
-Node: Job Control Variables324166
-Node: Command Line Editing325322
-Node: Introduction and Notation326993
-Node: Readline Interaction328616
-Node: Readline Bare Essentials329807
-Node: Readline Movement Commands331590
-Node: Readline Killing Commands332550
-Node: Readline Arguments334468
-Node: Searching335512
-Node: Readline Init File337698
-Node: Readline Init File Syntax338959
-Node: Conditional Init Constructs360239
-Node: Sample Init File364435
-Node: Bindable Readline Commands367559
-Node: Commands For Moving368763
-Node: Commands For History370814
-Node: Commands For Text375808
-Node: Commands For Killing379457
-Node: Numeric Arguments382490
-Node: Commands For Completion383629
-Node: Keyboard Macros387820
-Node: Miscellaneous Commands388507
-Node: Readline vi Mode394446
-Node: Programmable Completion395353
-Node: Programmable Completion Builtins403133
-Node: A Programmable Completion Example413828
-Node: Using History Interactively419075
-Node: Bash History Facilities419759
-Node: Bash History Builtins422764
-Node: History Interaction427772
-Node: Event Designators431392
-Node: Word Designators432746
-Node: Modifiers434506
-Node: Installing Bash436317
-Node: Basic Installation437454
-Node: Compilers and Options441176
-Node: Compiling For Multiple Architectures441917
-Node: Installation Names443610
-Node: Specifying the System Type445719
-Node: Sharing Defaults446435
-Node: Operation Controls447108
-Node: Optional Features448066
-Node: Reporting Bugs459159
-Node: Major Differences From The Bourne Shell460434
-Node: GNU Free Documentation License477284
-Node: Indexes502461
-Node: Builtin Index502915
-Node: Reserved Word Index509742
-Node: Variable Index512190
-Node: Function Index528682
-Node: Concept Index542466
+Node: Command Substitution95095
+Node: Arithmetic Expansion96450
+Node: Process Substitution97418
+Node: Word Splitting98538
+Node: Filename Expansion100482
+Node: Pattern Matching103082
+Node: Quote Removal107690
+Node: Redirections107985
+Node: Executing Commands117645
+Node: Simple Command Expansion118315
+Node: Command Search and Execution120425
+Node: Command Execution Environment122803
+Node: Environment125838
+Node: Exit Status127501
+Node: Signals129285
+Node: Shell Scripts132734
+Node: Shell Builtin Commands135761
+Node: Bourne Shell Builtins137799
+Node: Bash Builtins159260
+Node: Modifying Shell Behavior190077
+Node: The Set Builtin190422
+Node: The Shopt Builtin200835
+Node: Special Builtins216549
+Node: Shell Variables217528
+Node: Bourne Shell Variables217965
+Node: Bash Variables220069
+Node: Bash Features252884
+Node: Invoking Bash253897
+Node: Bash Startup Files259910
+Node: Interactive Shells265013
+Node: What is an Interactive Shell?265423
+Node: Is this Shell Interactive?266072
+Node: Interactive Shell Behavior266887
+Node: Bash Conditional Expressions270400
+Node: Shell Arithmetic275042
+Node: Aliases277986
+Node: Arrays280599
+Node: The Directory Stack286608
+Node: Directory Stack Builtins287392
+Node: Controlling the Prompt291652
+Node: The Restricted Shell294617
+Node: Bash POSIX Mode297214
+Node: Shell Compatibility Mode308487
+Node: Job Control315143
+Node: Job Control Basics315603
+Node: Job Control Builtins320605
+Node: Job Control Variables326005
+Node: Command Line Editing327161
+Node: Introduction and Notation328832
+Node: Readline Interaction330455
+Node: Readline Bare Essentials331646
+Node: Readline Movement Commands333429
+Node: Readline Killing Commands334389
+Node: Readline Arguments336307
+Node: Searching337351
+Node: Readline Init File339537
+Node: Readline Init File Syntax340798
+Node: Conditional Init Constructs362078
+Node: Sample Init File366274
+Node: Bindable Readline Commands369398
+Node: Commands For Moving370602
+Node: Commands For History372653
+Node: Commands For Text377647
+Node: Commands For Killing381296
+Node: Numeric Arguments384329
+Node: Commands For Completion385468
+Node: Keyboard Macros389659
+Node: Miscellaneous Commands390346
+Node: Readline vi Mode396285
+Node: Programmable Completion397192
+Node: Programmable Completion Builtins404972
+Node: A Programmable Completion Example415667
+Node: Using History Interactively420914
+Node: Bash History Facilities421598
+Node: Bash History Builtins424603
+Node: History Interaction429611
+Node: Event Designators433231
+Node: Word Designators434585
+Node: Modifiers436345
+Node: Installing Bash438156
+Node: Basic Installation439293
+Node: Compilers and Options443015
+Node: Compiling For Multiple Architectures443756
+Node: Installation Names445449
+Node: Specifying the System Type447558
+Node: Sharing Defaults448274
+Node: Operation Controls448947
+Node: Optional Features449905
+Node: Reporting Bugs460998
+Node: Major Differences From The Bourne Shell462273
+Node: GNU Free Documentation License479123
+Node: Indexes504300
+Node: Builtin Index504754
+Node: Reserved Word Index511581
+Node: Variable Index514029
+Node: Function Index530521
+Node: Concept Index544305
 
 End Tag Table
 

doc/bashref.texi

@@ -2440,7 +2440,8 @@ If @var{string} is null,
 matches of @var{pattern} are deleted
 and the @samp{/} following @var{pattern} may be omitted.
 
-Any unquoted instances of @samp{&} in @var{string} are replaced with the
+If the @code{patsub_replacement} shell option is enabled using @code{shopt},
+any unquoted instances of @samp{&} in @var{string} are replaced with the
 matching portion of @var{pattern}.
 This is intended to duplicate a common @code{sed} idiom.
 Backslash is used to quote @samp{&} in @var{string}; the backslash is removed
@@ -5786,6 +5787,13 @@ If the string is not translated, this has no effect.
 If set, Bash allows filename patterns which match no
 files to expand to a null string, rather than themselves.
 
+@item patsub_replacement
+If set, Bash
+expands occurrences of @samp{&} in the replacement string of pattern
+substitution to the text matched by the pattern, as described
+above (@pxref{Shell Parameter Expansion}).
+This option is enabled by default.
+
 @item progcomp
 If set, the programmable completion facilities
 (@pxref{Programmable Completion}) are enabled.

doc/version.texi

@@ -2,10 +2,10 @@
 Copyright (C) 1988-2021 Free Software Foundation, Inc.
 @end ignore
 
-@set LASTCHANGE Tue Oct 19 11:34:34 EDT 2021
+@set LASTCHANGE Mon Oct 25 11:21:24 EDT 2021
 
 @set EDITION 5.1
 @set VERSION 5.1
 
-@set UPDATED 19 October 2021
+@set UPDATED 25 October 2021
 @set UPDATED-MONTH October 2021

tests/RUN-ONE-TEST

@@ -1,4 +1,4 @@
-BUILD_DIR=/usr/local/build/chet/bash/bash-current
+BUILD_DIR=/usr/local/build/bash/bash-current
 THIS_SH=$BUILD_DIR/bash
 PATH=$PATH:$BUILD_DIR
 

tests/shopt.right

@@ -48,6 +48,7 @@ shopt -u nocaseglob
 shopt -u nocasematch
 shopt -u noexpand_translation
 shopt -u nullglob
+shopt -s patsub_replacement
 shopt -s progcomp
 shopt -u progcomp_alias
 shopt -s promptvars
@@ -70,6 +71,7 @@ shopt -s force_fignore
 shopt -s globasciiranges
 shopt -s hostcomplete
 shopt -s interactive_comments
+shopt -s patsub_replacement
 shopt -s progcomp
 shopt -s promptvars
 shopt -s sourcepath