ce3e080c0e
Announcing: KornShell 93u+m 1.0.0-beta.2 https://github.com/ksh93/ksh In May 2020, when every KornShell (ksh93) development project was abandoned, development was rebooted in a new fork based on the last stable AT&T version: ksh 93u+. This new fork is called ksh 93u+m as a permanent nod to its origin. We're restarting it at version 1.0. Seven months after the first beta, the second one is ready. Please test this second beta and report any bugs you find, or help us fix known bugs. We're now the default ksh93 in some OS distributions, at least Debian and Slackware! Even though we don't think it's stable release quality yet, the consensus seems to be that 93u+m is already much better than the last AT&T release. Main developers: Martijn Dekker, Johnothan King, hyenias Contributors: Andy Fiddaman, Anuradha Weeraman, Chase, Gordon Woodhull, Govind Kamat, Harald van Dijk, Lev Kujawski, Marc Wilson, Ryan Schmidt, Sterling Jensen HOW TO GET IT Please download the source code tarball from our GitHub releases page: https://github.com/ksh93/ksh/releases To build, follow the instructions in README.md or src/cmd/ksh93/README. HOW TO GET INVOLVED To report a bug, please open an issue at our GitHub page (see above). Alternatively, email me at martijn@inlv.org with your report. To get involved in development, read the brief policy information in README.md and then jump right in with a pull request or email a patch. See the TODO file in the top-level directory for a to-do list. *** MAIN CHANGES between 1.0.0-beta.1 and 1.0.0-beta.2 *** New features in built-in commands: - 'cd' now supports an -e option that, when combined with -P, verifies that $PWD is correct after changing directories; this helps detect access permission problems. See: https://www.austingroupbugs.net/view.php?id=253 - 'printf' now supports a -v option as in bash. This assigns formatted output directly to variables, which is very fast and will not strip final newline (\n) characters. - The 'return' command, when used to return from a function, can now return any status value in the 32-bit signed integer range, like on zsh. However, due to a traditional Unix kernel limitation, $? is still trimmed to its least significant 8 bits whenever leaving a (sub)shell environment. - 'test'/'[' now supports all the same operators as [[ (including =~, \<, \>) except for the different 'and'/'or' operators. Note that 'test'/'[' remains deprecated due to its unfixable pitfalls; [[ ... ]] is recommended instead. Shell language changes: - Several improvements were made to the --noexec shell code linter. - Arithmetic expressions in native ksh mode no longer interpret a number with a leading zero as octal in any context. Use 8#octalnumber instead (e.g. 8#400 == 256). Arithmetic expressions now also behave identically within and outside ((...)) and $((...)). - POSIX compatibility mode fixes (only applicable with the --posix shell option on): - A leading zero is now consistently recognised as introducing an octal number in all arithmetic contexts. - $((inf)) and $((nan)) are now interpreted as regular variables. - The '.' built-in no longer runs ksh functions and now only runs files. Bugs fixed: - '.' and '..' are now once again completed by tab completion. - If SIGINT is set to ignore, the interactive shell no longer exits on Ctrl+C. - ksh now builds and runs on Apple's new M1 hardware. - The 'return' and 'exit' commands no longer risk triggering actual signals by returning or exiting with a status > 256. - Ksh no longer behaves badly when parsing a type definition command ('typeset -T' or 'enum') without executing it or when executing it in a subshell. Types can now safely be defined in subshells and defined conditionally as in 'if condition; then enum ...; fi'. - Discipline functions, especially those applied to PS2 or .sh.tilde, will no longer crash your shell upon being interrupted or throwing an error. - Fixed a bug that could corrupt output if standard output is closed upon initialising the shell. - Fixed a bug in the [[ ... ]] compound command: the '!' logical negation operator now correctly negates another '!', e.g., [[ ! ! 1 -eq 1 ]] now returns 0/true. Note that this has always been the case for 'test'/'['. - Fixed SHLVL so that replacing ksh by itself (exec ksh) will not increase it. - Arithmetic expressions are no longer allowed to assign out-of-range values to variables of types declared with enum. - The 'time' keyword no longer makes the --errexit shell option ineffective. - Various bugs in libcmd built-in commands (those bound to the /opt/ast/bin path by default) have been fixed. - Various other crashing bugs have been fixed. Fixes for the shcomp byte code compiler: - shcomp is now able to compile scripts that define types using enum. - shcomp now refuses to mess up your terminal by writing bytecode to it. *** MAIN CHANGES between ksh 93u+ 2012-08-01 and 93u+m 1.0.0-beta.1 *** Hundreds of bugs have been fixed, including many serious/critical bugs. This includes upstreamed patches from OpenSUSE, Red Hat, and Solaris, fixes backported from the abandoned 93v- beta and ksh2020 fork, as well as many new fixes from the community. See the NEWS file for more information, and the git commit log for complete documentation of every fix. Incompatible changes have been minimised, but not at the expense of fixing bugs. For a list of potentially incompatible changes, see src/cmd/ksh93/COMPATIBILITY. Though there was a "no new features, bugfixes only" policy, some new features were found necessary, either to fix serious design flaws or to complete functionality that was evidently intended, but not finished. Below is a summary of these new features. New command line editor features: - The forward-delete and End keys are now handled as expected in the emacs and vi built-in line editors. - In the vi and emacs line editors, repeat count parameters can now also be used for the arrow keys and the forward-delete key. E.g., in emacs mode, <ESC> 7 <left-arrow> will now move the cursor seven positions to the left. In vi control mode, this would be entered as: 7 <left-arrow>. New shell language features: - The &>file redirection shorthand (for >file 2>&1) is now available for all scripts and interactive sessions and not only for profile/login scripts, bringing ksh 93u+m in line with mksh, bash, and zsh. - File name generation (a.k.a. pathname expansion, a.k.a. globbing) now never matches the special navigational names '.' (current directory) and '..' (parent directory). This change makes a pattern like .* useful; it now matches all hidden files (dotfiles) in the current directory, without the harmful inclusion of '.' and '..'. - Tilde expansion can now be extended or modified by defining a .sh.tilde.get or .sh.tilde.set discipline function. This replaces a 2004 undocumented attempt to add this functionality via a .sh.tilde command, which never worked and crashed the shell. See the manual for details on the new method. New features in built-in commands: - Usage error messages now show the --help/--man self-documentation options. - Path-bound built-ins (such as /opt/ast/bin/cat) can now be executed by invoking the canonical path, so the following will now work as expected: $ /opt/ast/bin/cat --version version cat (AT&T Research) 2012-05-31 - 'command -x' now looks for external commands only, skipping built-ins. In addition, its xargs-like functionality no longer freezes the shell on Linux and macOS, making it effectively a new feature on these systems. - 'redirect' now checks if all arguments are valid redirections before performing them. If an error occurs, it issues an error message instead of terminating the shell. - 'suspend' now refuses to suspend a login shell, as there is probably no parent shell to return to and the login session would freeze. - 'times' now gives high precision output in a POSIX compliant format. - 'typeset' now gives an informative error message if an incompatible combination of options is given. - 'whence -v/-a' now reports the location of autoloadable functions. New features in shell options: - A new --globcasedetect shell option is added on OSs where we can check for a case-insensitive file system (currently Windows/Cygwin, macOS, Linux and QNX 7.0+). When this option is turned on, file name generation (globbing), as well as file name tab completion on interactive shells, automatically become case-insensitive on file systems where the difference between upper and lower case is ignored for file names. This is transparently determined for each directory, so a path pattern that spans multiple file systems can be part case-sensitive and part case-insensitive. - A new --nobackslashctrl shell option disables the special escaping behaviour of the backslash character in the emacs and vi built-in editors. Particularly in the emacs editor, this makes it much easier to go backward, insert a forgotten backslash into a command, and then continue editing without having your next cursor key replace your backslash with garbage. Note that Ctrl+V (or whatever other character was set using 'stty lnext') always escapes all control characters in either editing mode. - A new --posix shell option has been added to ksh 93u+m that makes the ksh language more compatible with other shells by following the POSIX standard more closely. See the manual page for details. It is enabled by default if ksh is invoked as sh, otherwise it is disabled by default. - Enhancement to -G/--globstar: symbolic links to directories are now followed if they match a normal (non-**) glob pattern. For example, if '/lnk' is a symlink to a directory, '/lnk/**' and '/l?k/**' now work as you would expect. |
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| COPYRIGHT | ||
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| NEWS | ||
| README.md | ||
| TODO | ||
KornShell 93u+m
This repository is used to develop bugfixes to the last stable release (93u+ 2012-08-01) of ksh93, formerly developed by AT&T Software Technology (AST). The sources in this repository were forked from the GitHub AST repository which is no longer under active development.
For user-visible fixes, see NEWS and click on commit messages for full details. For all fixes, see the commit log. To see what's left to fix, see the issue tracker.
Policy
- Fixing bugs is main focus of the 1.x series. Major feature development is for future versions (2.x and up).
- No major rewrites. No refactoring code that is not fully understood.
- No changes in documented behaviour, except if required for compliance with the POSIX shell language standard which David Korn intended for ksh to follow.
- No 100% bug compatibility. Broken and undocumented behaviour gets fixed.
- No bureaucracy, no formalities. Just fix it, or report it: create issues, send pull requests. Every interested party is invited to contribute.
- To help increase everyone's understanding of this code base, fixes and significant changes should be fully documented in commit messages.
- Code style varies somewhat in this historic code base.
Your changes should match the style of the code surrounding them.
Indent with tabs, assuming an 8-space tab width.
Opening braces are on a line of their own, at the same indentation level
as their corresponding closing brace.
Comments always use
/*...*/. - Good judgment may override this policy.
Why?
Between 2017 and 2020 there was an ultimately unsuccessful attempt to breathe new life into the KornShell by extensively refactoring the last unstable AST beta version (93v-). While that ksh2020 branch is now abandoned and still has many critical bugs, it also had a lot of bugs fixed. More importantly, the AST issue tracker now contains a lot of documentation on how to fix those bugs, which made it possible to backport many of them to the last stable release instead. This ksh 93u+m reboot now incorporates many of these bugfixes, plus patches from OpenSUSE, Red Hat, and Solaris, as well as many new fixes from the community (1, 2). Though there are many bugs left to fix, we are confident at this point that 93u+m is already the least buggy branch of ksh93 ever released.
Build
To build ksh with a custom configuration of features, edit
src/cmd/ksh93/SHOPT.sh.
Then cd to the top directory and run:
bin/package make
The compiled binaries are stored in the arch directory, in a subdirectory
that corresponds to your architecture. The command bin/package host type
outputs the name of this subdirectory.
If you have trouble or want to tune the binaries, you may pass additional
compiler and linker flags. It is usually best to export these as environment
variables before running bin/package as they could change the name of
the build subdirectory of the arch directory, so exporting them is a
convenient way to keep them consistent between build and test commands.
Note that this system uses CCFLAGS instead of the usual CFLAGS.
An example that makes Solaris Studio cc produce a 64-bit binary:
export CCFLAGS="-m64 -O" LDFLAGS="-m64"
bin/package make
Alternatively you can append these to the command, and they will only be used for that command. You can also specify an alternative shell in which to run the build scripts this way. For example:
bin/package make SHELL=/bin/bash CCFLAGS="-O2 -I/opt/local/include" LDFLAGS="-L/opt/local/lib"
For more information run
bin/package help
Many other commands in this repo self-document via the --help, --man and
--html options; those that do have no separate manual page.
Test
After compiling, you can run the regression tests. Start by reading the information printed by:
bin/shtests --man
Install
Automated installation is not supported yet. To install manually:
cp arch/$(bin/package host type)/bin/ksh /usr/local/bin/
cp src/cmd/ksh93/sh.1 /usr/local/share/man/man1/ksh.1
(adapting the destination directories as required).
What is ksh93?
The following is the official AT&T description from 1993 that came with the ast-open distribution. The text is original, but hyperlinks were added here.
KSH-93 is the most recent version of the KornShell Language described in "The KornShell Command and Programming Language," by Morris Bolsky and David Korn of AT&T Bell Laboratories, ISBN 0-13-182700-6. The KornShell is a shell programming language, which is upward compatible with "sh" (the Bourne Shell), and is intended to conform to the IEEE P1003.2/ISO 9945.2 Shell and Utilities standard. KSH-93 provides an enhanced programming environment in addition to the major command-entry features of the BSD shell "csh". With KSH-93, medium-sized programming tasks can be performed at shell-level without a significant loss in performance. In addition, "sh" scripts can be run on KSH-93 without modification.
The code should conform to the IEEE POSIX 1003.1 standard and to the proposed ANSI C standard so that it should be portable to all such systems. Like the previous version, KSH-88, it is designed to accept eight bit character sets transparently, thereby making it internationally compatible. It can support multi-byte characters sets with some characteristics of the character set given at run time.
KSH-93 provides the following features, many of which were also inherent in KSH-88:
- Enhanced Command Re-entry Capability: The KSH-93 history function records commands entered at any shell level and stores them, up to a user-specified limit, even after you log off. This allows you to re-enter long commands with a few keystrokes - even those commands you entered yesterday. The history file allows for eight bit characters in commands and supports essentially unlimited size histories.
- In-line Editing: In "sh", the only way to fix mistyped commands is to backspace or retype the line. KSH-93 allows you to edit a command line using a choice of EMACS-TC or "vi" functions. You can use the in-line editors to complete filenames as you type them. You may also use this editing feature when entering command lines from your history file. A user can capture keystrokes and rebind keys to customize the editing interface.
- Extended I/O Capabilities: KSH-93 provides several I/O capabilities not
available in "sh", including the ability to:
- specify a file descriptor for input and output
- start up and run co-processes
- produce a prompt at the terminal before a read
- easily format and interpret responses to a menu
- echo lines exactly as output without escape processing
- format output using printf formats.
- read and echo lines ending in "\".
- Improved performance: KSH-93 executes many scripts faster than the System V Bourne shell. A major reason for this is that many of the standard utilities are built-in. To reduce the time to initiate a command, KSH-93 allows commands to be added as built-ins at run time on systems that support dynamic loading such as System V Release 4.
- Arithmetic: KSH-93 allows you to do integer arithmetic in any base from two to sixty-four. You can also do double precision floating point arithmetic. Almost the complete set of C language operators are available with the same syntax and precedence. Arithmetic expressions can be used to as an argument expansion or as a separate command. In addition, there is an arithmetic for command that works like the for statement in C.
- Arrays: KSH-93 supports both indexed and associative arrays. The subscript for an indexed array is an arithmetic expression, whereas, the subscript for an associative array is a string.
- Shell Functions and Aliases: Two mechanisms - functions and aliases - can be used to assign a user-selected identifier to an existing command or shell script. Functions allow local variables and provide scoping for exception handling. Functions can be searched for and loaded on first reference the way scripts are.
- Substring Capabilities: KSH-93 allows you to create a substring of any given string either by specifying the starting offset and length, or by stripping off leading or trailing substrings during parameter substitution. You can also specify attributes, such as upper and lower case, field width, and justification to shell variables.
- More pattern matching capabilities: KSH-93 allows you to specify extended regular expressions for file and string matches.
- KSH-93 uses a hierarchical name space for variables. Compound variables can be defined and variables can be passed by reference. In addition, each variable can have one or more disciplines associated with it to intercept assignments and references.
- Improved debugging: KSH-93 can generate line numbers on execution traces. Also, I/O redirections are now traced. There is a DEBUG trap that gets evaluated before each command so that errors can be localized.
- Job Control: On systems that support job control, including System V Release 4, KSH-93 provides a job-control mechanism almost identical to that of the BSD "csh", version 4.1. This feature allows you to stop and restart programs, and to move programs between the foreground and the background.
- Added security: KSH-93 can execute scripts which do not have read permission and scripts which have the setuid and/or setgid set when invoked by name, rather than as an argument to the shell. It is possible to log or control the execution of setuid and/or setgid scripts. The noclobber option prevents you from accidentally erasing a file by redirecting to an existing file.
- KSH-93 can be extended by adding built-in commands at run time. In addition, KSH-93 can be used as a library that can be embedded into an application to allow scripting.
Documentation for KSH-93 consists of an "Introduction to KSH-93", "Compatibility with the Bourne Shell" and a manual page and a README file. In addition, the "New KornShell Command and Programming Language" book is available from Prentice Hall.