expr(1) should usually not be used as various forms of parameter expansion
and arithmetic expansion replicate most of its functionality in an easier
way.
getopt(1) should not be used at all in new code. Instead, getopts(1) or
entirely manual parsing should be used.
MFC after: 1 week
Unless $! has been referenced for a particular job or $! still contains that
job's pid, forget about it after it has terminated. If $! has been
referenced, remember the job until the wait builtin has reported its
completion (either with the pid as parameter or without parameters).
In interactive mode, jobs are forgotten after termination has been reported,
which happens before primary prompts and through the jobs builtin. Even
then, though, remember a job if $! has been referenced.
This is similar to what is suggested by POSIX and should fix most memory
leaks (which also tend to cause sh to use more CPU time) with long running
scripts that start background jobs.
Caveats:
* Repeatedly referencing $! without ever doing 'wait', like
while :; do foo & echo started foo: $!; sleep 60; done
will still use a lot of memory and CPU time in the long run.
* The jobs and jobid builtins do not cause a job to be remembered for longer
like expanding $! does.
PR: bin/55346
* Move the "environment variables" that do not need exporting to be
effective or that are set by the shell without exporting to a new section
"Special Variables".
* Add special variables LINENO and PPID.
* Add environment variables LANG, LC_* and PWD; also describe ENV under
environment variables.
This makes sh a bit more friendly in single user mode, make buildenv, chroot
and the like, and matches other shells.
The -o emacs can be overridden on the command line or in the ENV file.
Note that the following sentence
> Enclosing the full parameter expansion string in double-quotes does not
> cause the following four varieties of pattern characters to be quoted,
> whereas quoting characters within the braces has this effect.
is now true, but used to be incorrect.
* avoid unnecessary fork
* allow executing builtins via command
* executing a special builtin via command removes its special properties
Obtained from: NetBSD (parts)
This seems more useful and will likely be in the next POSIX standard.
Also document more precisely in the man page what set -u does (note that
$@, $* and $! are the only special parameters that can ever be unset, all
the others are always set, although they may be empty).
I do not consider this a bug because POSIX permits it and argument strings
and environment variables cannot contain '\0' anyway.
PR: bin/25542
MFC after: 2 weeks
The exit status may exceed 255 in some cases (return); even though it seems
unwise to rely on this, it is also unwise to assume that $? is always
between 0 and 255.
This resolves bin/124748 by documenting that 'exit -1' is not valid.
PR: bin/124748
Approved by: ed (mentor)
character.
This avoids using non-standard behaviour of the old (upto FreeBSD 7) TTY
layer: it reprocesses the input queue when switching to canonical mode. The
new TTY layer does not provide this functionality and so read -t worked
very poorly (first character is not echoed, cannot be backspaced but is
still read).
This also agrees with what most other shells with read -t do.
PR: bin/129566
Reviewed by: stefanf
Approved by: ed (mentor)
When I imported the MPSAFE TTY code, I added the -p flag to sh(1)'s
ulimit, but I forgot to document it in the appropriate manual page.
Requested by: stefanf
process leader for each job. Now the last specified option for the output
format (-l, -p or -s) wins, previously -s trumped -l.
PR: 99926
Submitted by: Ed Schouten and novel (patches modified by me)
Utilities option. Its value is printed at the beginning of the line if tracing
(-x) is active. PS4 defaults to the string "+ " which is compatible with the
old behaviour to always print "+ ".
We still need to expand variables in PS1, PS2 and PS4.
PR: 46441 (part of)
Submitted by: schweikh
Obtained from: NetBSD
itself and its children. Instead of calling times() (as implied by POSIX) this
implementation directly calls getrusage() to get the times because this is more
convenient.
promised by the Argument List Processing section introduction.
What follows the option in the options list is its long name,
not its argument (as is the case for the -c option). Also
sort references in the SEE ALSO section.
Approved by: re (blanket)
- Move the description of the ``-c string'' option closer to the option itself.
- Add an ENVIRONMENT section (1)
- Add more .Xr cross references to the SEE ALSO section.
Obtained from: NetBSD (1)
