fix for heuristic to detect case statements when parsing $() command substitutions to find history expansion; fix for history not being saved if a SIGHUP arrives during $PROMPT_COMMAND execution; workaround for Cygwin bug that results in bash incorrectly calculating the system pipe size

doc/bash.info

@@ -1,9 +1,9 @@
 This is bash.info, produced by makeinfo version 7.2 from bashref.texi.
 
 This text is a brief description of the features that are present in the
-Bash shell (version 5.3, 27 February 2026).
+Bash shell (version 5.3, 3 March 2026).
 
-   This is Edition 5.3, last updated 27 February 2026, of ‘The GNU Bash
+   This is Edition 5.3, last updated 3 March 2026, of ‘The GNU Bash
 Reference Manual’, for ‘Bash’, Version 5.3.
 
    Copyright © 1988-2026 Free Software Foundation, Inc.
@@ -26,10 +26,10 @@ Bash Features
 *************
 
 This text is a brief description of the features that are present in the
-Bash shell (version 5.3, 27 February 2026).  The Bash home page is
+Bash shell (version 5.3, 3 March 2026).  The Bash home page is
 <http://www.gnu.org/software/bash/>.
 
-   This is Edition 5.3, last updated 27 February 2026, of ‘The GNU Bash
+   This is Edition 5.3, last updated 3 March 2026, of ‘The GNU Bash
 Reference Manual’, for ‘Bash’, Version 5.3.
 
    Bash contains features that appear in other popular shells, and some
@@ -1896,16 +1896,17 @@ introduce indirection.
    In each of the cases below, WORD is subject to tilde expansion,
 parameter expansion, command substitution, and arithmetic expansion.
 
-   When not performing substring expansion, using the forms described
-below (e.g., ‘:−’), Bash tests for a parameter that is unset or null.
-Omitting the colon results in a test only for a parameter that is unset.
-Put another way, if the colon is included, the operator tests for both
-PARAMETER's existence and that its value is not null; if the colon is
-omitted, the operator tests only for existence.
+   When performing the first four expansions documented below (‘:-’,
+‘:=’, ‘:?’, and ‘:+’), including the colon, Bash tests for a parameter
+that is unset or null.  Omitting the colon results in a test only for a
+parameter that is unset.  Put another way, if the colon is included, the
+operator tests for both PARAMETER's existence and that its value is not
+null; if the colon is omitted, the operator tests only for existence.
 
 ‘${PARAMETER:−WORD}’
-     If PARAMETER is unset or null, the expansion of WORD is
-     substituted.  Otherwise, the value of PARAMETER is substituted.
+     If PARAMETER is unset or null, or unset if the colon is not
+     present, the expansion of WORD is substituted.  Otherwise, the
+     value of PARAMETER is substituted.
 
           $ v=123
           $ echo ${v-unset}
@@ -1922,10 +1923,11 @@ omitted, the operator tests only for existence.
           unset-or-null
 
 ‘${PARAMETER:=WORD}’
-     If PARAMETER is unset or null, the expansion of WORD is assigned to
-     PARAMETER, and the result of the expansion is the final value of
-     PARAMETER.  Positional parameters and special parameters may not be
-     assigned in this way.
+     If PARAMETER is unset or null, or unset if the colon is not
+     present, the expansion of WORD is assigned to PARAMETER, and the
+     result of the expansion is the final value of PARAMETER.
+     Positional parameters and special parameters may not be assigned in
+     this way.
 
           $ unset var
           $ : ${var=DEFAULT}
@@ -1945,12 +1947,13 @@ omitted, the operator tests only for existence.
           DEFAULT
 
 ‘${PARAMETER:?WORD}’
-     If PARAMETER is null or unset, the shell writes the expansion of
-     WORD (or a message to that effect if WORD is not present) to the
-     standard error and, if it is not interactive, exits with a non-zero
-     status.  An interactive shell does not exit, but does not execute
-     the command associated with the expansion.  Otherwise, the value of
-     PARAMETER is substituted.
+     If PARAMETER is unset or null, or unset if the colon is not
+     present, the shell writes the expansion of WORD (or a message to
+     that effect if WORD is not present) to the standard error and, if
+     it is not interactive, exits with a non-zero status.  An
+     interactive shell does not exit, but does not execute the command
+     associated with the expansion.  Otherwise, the value of PARAMETER
+     is substituted.
 
           $ var=
           $ : ${var:?var is unset or null}
@@ -1967,9 +1970,9 @@ omitted, the operator tests only for existence.
           123
 
 ‘${PARAMETER:+WORD}’
-     If PARAMETER is null or unset, nothing is substituted, otherwise
-     the expansion of WORD is substituted.  The value of PARAMETER is
-     not used.
+     If PARAMETER is unset or null, or unset if the colon is not
+     present, nothing is substituted, otherwise the expansion of WORD is
+     substituted.  The value of PARAMETER is not used.
 
           $ var=123
           $ echo ${var:+var is set and not null}
@@ -7163,7 +7166,7 @@ shell variables may also be referenced by name without using the
 parameter expansion syntax.  This means you can use X, where X is a
 shell variable name, in an arithmetic expression, and the shell will
 evaluate its value as an expression and use the result.  A shell
-variable that is null or unset evaluates to 0 when referenced by name in
+variable that is unset or null evaluates to 0 when referenced by name in
 an expression.
 
    The value of a variable is evaluated as an arithmetic expression when
@@ -13735,138 +13738,138 @@ D.5 Concept Index
 
 
 Tag Table:
-Node: Top901
-Node: Introduction2842
-Node: What is Bash?3055
-Node: What is a shell?4188
-Node: Definitions6798
-Node: Basic Shell Features10125
-Node: Shell Syntax11349
-Node: Shell Operation12376
-Node: Quoting13667
-Node: Escape Character15005
-Node: Single Quotes15540
-Node: Double Quotes15889
-Node: ANSI-C Quoting17234
-Node: Locale Translation18628
-Node: Creating Internationalized Scripts20031
-Node: Comments24229
-Node: Shell Commands24996
-Node: Reserved Words25935
-Node: Simple Commands27078
-Node: Pipelines27740
-Node: Lists30996
-Node: Compound Commands32945
-Node: Looping Constructs33954
-Node: Conditional Constructs36503
-Node: Command Grouping51640
-Node: Coprocesses53132
-Node: GNU Parallel55818
-Node: Shell Functions56736
-Node: Shell Parameters65184
-Node: Positional Parameters70085
-Node: Special Parameters71175
-Node: Shell Expansions74636
-Node: Brace Expansion76825
-Node: Tilde Expansion80161
-Node: Shell Parameter Expansion83116
-Node: Command Substitution103763
-Node: Arithmetic Expansion107614
-Node: Process Substitution108790
-Node: Word Splitting109898
-Node: Filename Expansion112342
-Node: Pattern Matching115566
-Node: Quote Removal121332
-Node: Redirections121636
-Node: Executing Commands131892
-Node: Simple Command Expansion132559
-Node: Command Search and Execution134667
-Node: Command Execution Environment137111
-Node: Environment140637
-Node: Exit Status142540
-Node: Signals144599
-Node: Shell Scripts149547
-Node: Shell Builtin Commands152845
-Node: Bourne Shell Builtins155186
-Node: Bash Builtins181905
-Node: Modifying Shell Behavior219641
-Node: The Set Builtin219983
-Node: The Shopt Builtin231977
-Node: Special Builtins249030
-Node: Shell Variables250019
-Node: Bourne Shell Variables250453
-Node: Bash Variables252961
-Node: Bash Features292245
-Node: Invoking Bash293259
-Node: Bash Startup Files299843
-Node: Interactive Shells305085
-Node: What is an Interactive Shell?305493
-Node: Is this Shell Interactive?306155
-Node: Interactive Shell Behavior306979
-Node: Bash Conditional Expressions310740
-Node: Shell Arithmetic316157
-Node: Aliases319484
-Node: Arrays322618
-Node: The Directory Stack330321
-Node: Directory Stack Builtins331118
-Node: Controlling the Prompt335563
-Node: The Restricted Shell338447
-Node: Bash POSIX Mode341540
-Node: Shell Compatibility Mode361356
-Node: Job Control370363
-Node: Job Control Basics370820
-Node: Job Control Builtins377188
-Node: Job Control Variables383976
-Node: Command Line Editing385207
-Node: Introduction and Notation386910
-Node: Readline Interaction389262
-Node: Readline Bare Essentials390450
-Node: Readline Movement Commands392258
-Node: Readline Killing Commands393254
-Node: Readline Arguments395277
-Node: Searching396367
-Node: Readline Init File398610
-Node: Readline Init File Syntax399913
-Node: Conditional Init Constructs426864
-Node: Sample Init File431249
-Node: Bindable Readline Commands434369
-Node: Commands For Moving435907
-Node: Commands For History438371
-Node: Commands For Text443762
-Node: Commands For Killing447887
-Node: Numeric Arguments450675
-Node: Commands For Completion451827
-Node: Keyboard Macros457523
-Node: Miscellaneous Commands458224
-Node: Readline vi Mode465767
-Node: Programmable Completion466744
-Node: Programmable Completion Builtins476480
-Node: A Programmable Completion Example488217
-Node: Using History Interactively493562
-Node: Bash History Facilities494243
-Node: Bash History Builtins497978
-Node: History Interaction505573
-Node: Event Designators510523
-Node: Word Designators512101
-Node: Modifiers514493
-Node: Installing Bash516430
-Node: Basic Installation517546
-Node: Compilers and Options521422
-Node: Compiling For Multiple Architectures522172
-Node: Installation Names523925
-Node: Specifying the System Type526159
-Node: Sharing Defaults526905
-Node: Operation Controls527619
-Node: Optional Features528638
-Node: Reporting Bugs541361
-Node: Major Differences From The Bourne Shell542718
-Node: GNU Free Documentation License564145
-Node: Indexes589322
-Node: Builtin Index589773
-Node: Reserved Word Index596871
-Node: Variable Index599316
-Node: Function Index616729
-Node: Concept Index630862
+Node: Top893
+Node: Introduction2826
+Node: What is Bash?3039
+Node: What is a shell?4172
+Node: Definitions6782
+Node: Basic Shell Features10109
+Node: Shell Syntax11333
+Node: Shell Operation12360
+Node: Quoting13651
+Node: Escape Character14989
+Node: Single Quotes15524
+Node: Double Quotes15873
+Node: ANSI-C Quoting17218
+Node: Locale Translation18612
+Node: Creating Internationalized Scripts20015
+Node: Comments24213
+Node: Shell Commands24980
+Node: Reserved Words25919
+Node: Simple Commands27062
+Node: Pipelines27724
+Node: Lists30980
+Node: Compound Commands32929
+Node: Looping Constructs33938
+Node: Conditional Constructs36487
+Node: Command Grouping51624
+Node: Coprocesses53116
+Node: GNU Parallel55802
+Node: Shell Functions56720
+Node: Shell Parameters65168
+Node: Positional Parameters70069
+Node: Special Parameters71159
+Node: Shell Expansions74620
+Node: Brace Expansion76809
+Node: Tilde Expansion80145
+Node: Shell Parameter Expansion83100
+Node: Command Substitution103948
+Node: Arithmetic Expansion107799
+Node: Process Substitution108975
+Node: Word Splitting110083
+Node: Filename Expansion112527
+Node: Pattern Matching115751
+Node: Quote Removal121517
+Node: Redirections121821
+Node: Executing Commands132077
+Node: Simple Command Expansion132744
+Node: Command Search and Execution134852
+Node: Command Execution Environment137296
+Node: Environment140822
+Node: Exit Status142725
+Node: Signals144784
+Node: Shell Scripts149732
+Node: Shell Builtin Commands153030
+Node: Bourne Shell Builtins155371
+Node: Bash Builtins182090
+Node: Modifying Shell Behavior219826
+Node: The Set Builtin220168
+Node: The Shopt Builtin232162
+Node: Special Builtins249215
+Node: Shell Variables250204
+Node: Bourne Shell Variables250638
+Node: Bash Variables253146
+Node: Bash Features292430
+Node: Invoking Bash293444
+Node: Bash Startup Files300028
+Node: Interactive Shells305270
+Node: What is an Interactive Shell?305678
+Node: Is this Shell Interactive?306340
+Node: Interactive Shell Behavior307164
+Node: Bash Conditional Expressions310925
+Node: Shell Arithmetic316342
+Node: Aliases319669
+Node: Arrays322803
+Node: The Directory Stack330506
+Node: Directory Stack Builtins331303
+Node: Controlling the Prompt335748
+Node: The Restricted Shell338632
+Node: Bash POSIX Mode341725
+Node: Shell Compatibility Mode361541
+Node: Job Control370548
+Node: Job Control Basics371005
+Node: Job Control Builtins377373
+Node: Job Control Variables384161
+Node: Command Line Editing385392
+Node: Introduction and Notation387095
+Node: Readline Interaction389447
+Node: Readline Bare Essentials390635
+Node: Readline Movement Commands392443
+Node: Readline Killing Commands393439
+Node: Readline Arguments395462
+Node: Searching396552
+Node: Readline Init File398795
+Node: Readline Init File Syntax400098
+Node: Conditional Init Constructs427049
+Node: Sample Init File431434
+Node: Bindable Readline Commands434554
+Node: Commands For Moving436092
+Node: Commands For History438556
+Node: Commands For Text443947
+Node: Commands For Killing448072
+Node: Numeric Arguments450860
+Node: Commands For Completion452012
+Node: Keyboard Macros457708
+Node: Miscellaneous Commands458409
+Node: Readline vi Mode465952
+Node: Programmable Completion466929
+Node: Programmable Completion Builtins476665
+Node: A Programmable Completion Example488402
+Node: Using History Interactively493747
+Node: Bash History Facilities494428
+Node: Bash History Builtins498163
+Node: History Interaction505758
+Node: Event Designators510708
+Node: Word Designators512286
+Node: Modifiers514678
+Node: Installing Bash516615
+Node: Basic Installation517731
+Node: Compilers and Options521607
+Node: Compiling For Multiple Architectures522357
+Node: Installation Names524110
+Node: Specifying the System Type526344
+Node: Sharing Defaults527090
+Node: Operation Controls527804
+Node: Optional Features528823
+Node: Reporting Bugs541546
+Node: Major Differences From The Bourne Shell542903
+Node: GNU Free Documentation License564330
+Node: Indexes589507
+Node: Builtin Index589958
+Node: Reserved Word Index597056
+Node: Variable Index599501
+Node: Function Index616914
+Node: Concept Index631047
 
 End Tag Table