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It’s official as the first public release of bash 5.0 is now available for download. Bash 5.0 is the fifth major release of bash.
Bash 5.0 Released With New Features
From the mailing list:
This release fixes several outstanding bugs in bash-4.4 and introduces several new features. The most significant bug fixes are an overhaul of how nameref variables resolve and a number of potential out-of-bounds memory errors discovered via fuzzing. There are a number of changes to the expansion of $@ and $* in various contexts where word splitting is not performed to conform to a Posix standard interpretation, and additional changes to resolve corner cases for Posix conformance. The most notable new features are several new shell variables: BASH_ARGV0, EPOCHSECONDS, and EPOCHREALTIME. The `history' builtin can remove ranges of history entries and understands negative arguments as offsets from the end of the history list. There is an option to allow local variables to inherit the value of a variable with the same name at a preceding scope. There is a new shell option that, when enabled, causes the shell to attempt to expand associative array subscripts only once (this is an issue when they are used in arithmetic expressions). The `globasciiranges' shell option is now enabled by default; it can be set to off by default at configuration time. There are a few incompatible changes between bash-4.4 and bash-5.0. The changes to how nameref variables are resolved means that some uses of namerefs will behave differently, though I have tried to minimize the compatibility issues. By default, the shell only sets BASH_ARGC and BASH_ARGV at startup if extended debugging mode is enabled; it was an oversight that it was set unconditionally and caused performance issues when scripts were passed large numbers of arguments. Bash can be linked against an already-installed Readline library rather than the private version in lib/readline if desired. Only readline-8.0 and later versions are able to provide all of the symbols that bash-5.0 requires; earlier versions of the Readline library will not work correctly. A complete list of changes between bash-4.4 and bash-5.0 is available in the file CHANGES; the complete list is too large to include in this
New Features in Bash:
- The `wait’ builtin can now wait for the last process substitution created.
- There is an EPOCHSECONDS variable, which expands to the time in seconds
since the Unix epoch.
- There is an EPOCHREALTIME variable, which expands to the time in seconds
since the Unix epoch with microsecond granularity.
- New loadable builtins: rm, stat, fdflags.
- BASH_ARGV0: a new variable that expands to $0 and sets $0 on assignment.
- When supplied a numeric argument, the shell-expand-line bindable readline
command does not perform quote removal and suppresses command and process