61d9bca581
Continuing alias substitution after 'command' (due to the final
space in the alias) is inherently broken and doing so by default is
incompatible with the POSIX standard, as aliases may contain
arbitrary shell grammar.
For instance, until the previous commit, the POSIX standard 'times'
command was an alias: times='{ { time;} 2>&1;}' -- and so, of
course, 'command times' gave a syntax error, although this is
a perfectly valid POSIX idiom that must be supported.
'command' is specified by POSIX as a regular builtin, not an alias.
Therefore it should always bypass aliases just as it bypasses
functions to expose standard builtin and external commands.
I can only imagine that the reason for this command='command '
alias was that some standard commands themselves were implemented
as aliases, and POSIX requires that standard commands are
accessible with the 'command' prefix. But implementing standard
commands as aliases is itself inherently broken. It never worked
for 'command times', as shown; and in any case, removing all
aliases with 'unalias -a' should not get rid of standard commands.
Similarly, the default alias nohup='nohup ' is also harmful.
Anyone who really wants to keep this behaviour can just define
these aliases themselves in their script or ~/.kshrc file.
src/cmd/ksh93/data/aliases.c:
- Remove default alias command='command '.
- Remove default alias nohup='nohup '.
src/cmd/ksh93/sh.1
- Remove the above default aliases from the list.
- Mention that the 'command' builtin does not search for aliases.
(cherry picked from commit 5cfe7c4e2015b7445da24983af5008035c4b6e1e)
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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.
To see what's fixed, see NEWS and click on commit messages for full details.
To see what's left to fix, see TODO.
Policy
- No new features. Bug fixes only.
- 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.
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 makes it possible to backport many of them to the last stable release instead.
In February 2020, having concluded the AST 93v- beta was too broken to base new work on, others decided to start a new fork based on the last stable 93u+ 2012-08-01 release. Unfortunately, as of June 2020, the new ksh-community organisation is yet to see any significant activity four months after its bootstrapping. I hope that will change; I am ready to join efforts with them at any time, as well as anyone else who wants to contribute.
The last stable ksh93 release from 2012 is the least buggy release currently available, but it still has many serious bugs. So it is well past time to start fixing those bugs, leave the rest of the code alone, and get an improved release out there.
Build
After cloning this repo, cd to the top directory of it and run:
./bin/package make
If you have trouble or want to tune the binaries, you may pass additional compiler and linker flags by appending it to the command shown above. E.g.:
./bin/package make \
SHELL=/bin/bash CCFLAGS="-xc99 -D_XPG6 -m64 -xO4" LDFLAGS="-m64"
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