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#5754: bash-5.3
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Reporter: Bruce Dubbs | Owner: lfs-book
Type: enhancement | Status: new
Priority: normal | Milestone: 12.4
Component: Book | Version: git
Severity: normal | Resolution:
Keywords: |
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Comment (by Bruce Dubbs):
This is a terse description of the new features added to bash-5.3 since
the release of bash-5.2. As always, the manual page (doc/bash.1) is
the place to look for complete descriptions.
1. New Features in Bash
{{{
a. When checking whether a script file argument is a binary file, check
the
first two lines of a script if the first line begins with `#!'.
b. Bash does a better job of preserving user-supplied quotes around a word
completion, instead of requoting it.
c. Bash reports the starting line number in an error message about an
unterminated compound command like `if' without a `fi'.
d. Implement the POSIX requirement that running the `jobs' builtin removes
jobs from the jobs list.
f. Call bash signal handlers while executing programmable completion
commands,
instead of readline's.
g. Print an error message if a regular expression used with [[ fails to
compile.
h. The `umask' builtin now has additional features for full POSIX
conformance.
i. `type -a -P' reports both hashed pathnames and the result of a $PATH
search.
j. `trap' has a new -P option that prints the trap action associated with
each
signal argument.
k. The `command' builtin preceding a declaration builtin (e.g., `declare')
preserves the special asisgnment statement parsing for the declaration
builtin. This is a new POSIX requirement.
l. `printf' uses the `alternate form' for %q and %Q to force single
quoting.
m. `printf' now interprets %ls (%S) and %lc (%C) as referring to wide
strings
and characters, respectively, when in a multibyte locale.
n. The shell can be compiled with a different default value for the
patsub_replacement option.
o. Check for window size changes during trap commands, `bind -x' commands,
and programmable completion.
p. Treat a NULL value for $PATH as equivalent to ".".
p. New loadable builtins: kv, strptime
q. GLOBSORT: new variable to specify how to sort the results of pathname
expansion (name, size, blocks, mtime, atime, ctime, numeric, none) in
ascending or descending order.
r. `compgen' has a new option: -V varname. If supplied, it stores the
generated
completions into VARNAME instead of printing them on stdout.
s. New form of command substitution: ${ command; } or ${|command;} to
capture
the output of COMMAND without forking a child process and using pipes.
t. array_expand_once: new shopt option, replaces assoc_expand_once
u. complete/compopt new option: fullquote; sets rl_full_quoting_desired so
all
possible completions are quoted as if they were filenames.
v. Command timing now allows precisions up to 6 digits instead of 3 in
$TIMEFORMAT.
w. BASH_MONOSECONDS: new dynamic variable that returns the value of the
system's monotonic clock, if one is available.
x. BASH_TRAPSIG: new variable, set to the numeric signal number of the
trap
being executed while it's running.
y. The checkwinsize option can be used in subshell commands started from
interactive shells.
z. In posix mode, the test command < and > binary primaries compare
strings
using the current locale.
aa. bind -x allows new key binding syntax: separate the key sequence and
the
command string with whitespace, but require the command string to be
double-quoted if this is used. This allows different quoting options
for
the command string.
bb. Print commands bound to key sequences using `bind -x' with the new key
binding syntax it allows.
cc. `read' has a new `-E' option to use readline but with the default bash
completion (including programmable completion).
dd. New bindable readline command name: `bash-vi-complete'.
ee. New test builtin behavior when parsing a parenthesized subexpression
and
test was given more than 4 arguments: scan forward for a closing paren
and
call posixtest() if there are 4 or fewer arguments between the
parentheses.
Added for compatibility with coreutils test, dependent on the shell
compatibility level. Such expressions remain ambiguous.
ff. MULTIPLE_COPROCS is now enabled by default.
gg. The `bind' builtin interprets additional non-option arguments after -p
or
-P as bindable command names and restricts output to the bindings for
those names.
hh. Bash now uses the login shell for $BASH if the shell is named `su' or
`-su'.
ii. Bash now prints job notifications if an interactive shell is running a
trap,
even though the shell is not interactive at that moment.
jj. Programmable completion allows a new compspec loaded after a
completion
function returns 124 to be used in more cases.
kk. ./source has a new -p PATH option, which makes it use the PATH
argument
instead of $PATH to look for the file.
ll. Documentation has been significantly updated.
mm. `wait -n' can now return terminated process substitutions, jobs about
which the user has already been notified (like `wait' without
options),
nn. `wait -n' removes jobs from the jobs table or list of terminated
children
when in posix mode.
oo. Changed the `wait' builtin behavior regarding process substitutions to
match the documentation.
pp. There is a new `bash_source_fullpath' shopt option, which makes bash
put
full pathnames into BASH_SOURCE, and a way to set a default value for
it
at configure time.
qq. Posix mode now forces job notifications to occur when the new edition
of
POSIX specifies (since it now specifies them).
rr. Interactive shells don't print job notifications while sourcing
scripts.
ss. The parser prints more information about the command it's trying to
parse
when it encounters EOF before completing the command.
tt. Posix mode no longer requires function names to be valid shell
identifiers.
uu. If `exit' is run in a trap and not supplied an exit status argument,
it
uses the value of $? from before the trap only if it's run at the
trap's
`top level' and would cause the trap to end (that is, not in a
subshell).
This is from Posix interp 1602.
vv. There is a new `fltexpr' loadable builtin to perform floating-point
arithmetic similarly to `let'.
ww. The `install-strip' and `strip' Makefile targets now deal with cross-
compiling.
}}}
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