If CDPATH is used non-trivially or the operand is "-", cd writes the
directory actually switched to. (We currently do this only in interactive
shells, but POSIX requires this in non-interactive shells as well.)
As mentioned in Austin group bug #1045, cd shall not return an error while
leaving the current directory changed. Therefore, ignore any write error.
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
Per Austin group issue #884, always set IFS to $' \t\n'. As before, IFS will
be exported iff it was in the environment.
Most shells (e.g. bash, ksh93 and mksh) already did this. This change
improves predictability, in that scripts can simply rely on the default
value.
However, the effect on security is little, since applications should not be
calling the shell with attacker-controlled environment variable names in the
first place and other security-sensitive variables such as PATH should be
and are imported by the shell.
When using a new sh with an old (before 10.2) libc wordexp(), IFS is no
longer passed on. Otherwise, wordexp() continues to pass along IFS from the
environment per its documentation.
Discussed with: pfg
Relnotes: yes
POSIX requires this to prevent entering function definitions in history but
this implementation does nothing except retain the option's value. In ksh88,
function definitions were usually entered in the history file, even when
they came from ~/.profile and the $ENV file, to allow displaying their
definitions.
This is also the first option that does not have a letter.
The parser considered 'trap exit INT' to reset the default for both EXIT and
INT. This beahvior is not POSIX compliant. This was avoided if a value was
specified for 'exit', but then disallows exiting with the signal received. A
possible workaround is using ' exit'.
However POSIX does allow this type of behavior if the parameters are all
integers. Fix the handling for this and clarify its support in the manpage
since it is specifically allowed by POSIX.
Differential Revision: https://reviews.freebsd.org/D2325
Reviewed by: jilles
MFC after: 2 weeks
Per Austin Group issue #459, shifting zero positional parameters may or may
not be considered an operand error (which causes the shell to exit in most
cases).
If an alias's value ends with a space or tab, the next word is also
checked for aliases.
This is a POSIX feature. It is useful with utilities like command and
nohup (alias them to themselves followed by a space).
Formerly, return always returned from a function if it was called from a
function, even if there was a closer dot script. This was for compatibility
with the Bourne shell which only allowed returning from functions.
Other modern shells and POSIX return from the function or the dot script,
whichever is closest.
Git 1.8.4's rebase --continue depends on the POSIX behaviour.
Reported by: Christoph Mallon, avg
* If read -t times out, return status as if interrupted by SIGALRM
(formerly 1).
* If a trapped signal interrupts read, return status 128+sig (formerly 1).
* If [EINTR] occurs but there is no trap, retry the read (for example
because of a SIGWINCH in interactive mode).
* If a read error occurs, write an error message and return status 2.
As before, a variable assignment error returns 2 and discards the remaining
data read.
In some other shells, things like $((a);(b)) are command substitutions.
Also, there are shells that have an extension ((ARITH)) that evaluates an
arithmetic expression and returns status 1 if the result is zero, 0
otherwise. This extension may lead to ambiguity with two subshells starting
in sequence.
Instead of rechecking relative paths for all hashed utilities after a cd,
track if any utility in cmdtable depends on a relative path in PATH.
If there is such a utility, cd clears the entire table.
As a result, the '*' in hash no longer happens.
Examples:
export x=~
now expands the tilde
local y=$1
is now safe, even if $1 contains IFS characters or metacharacters.
For a word to "look like an assignment", it must start with a name followed
by an equals sign, none of which may be quoted.
The special treatment applies when the first word (potentially after
"command") is "export", "readonly" or "local". There may be quoting
characters but no expansions. If "local" is overridden with a function there
is no special treatment ("export" and "readonly" cannot be overridden with a
function).
If things like
local arr=(1 2 3)
are ever allowed in the future, they cannot call a "local" function. This
would either be a run-time error or it would call the builtin.
This matches Austin Group bug #351, planned for the next issue of POSIX.1.
PR: bin/166771
quotation. Also make sure we have the same amount of columns in each row as
the number of columns we specify in the head arguments.
Reviewed by: brueffer
Because sh executes commands in subshell environments without forking in
more and more cases (particularly from 8.0 on), it makes sense to describe
subshell environments more precisely using ideas from POSIX, together with
some FreeBSD-specific items.
In particular, the hash and times builtins may not behave as if their state
is copied for a subshell environment while leaving the parent shell
environment unchanged.
* Shell patterns are also for ${var#pat} and the like.
* An '!' by itself will not trigger pathname generation so do not call it a
meta-character, even though it has a special meaning directly after an
'['.
* Character ranges are locale-dependent.
* A '^' will complement a character class like '!' but is non-standard.
MFC after: 1 week
POSIX requires a -h option to sh and set, to locate and remember utilities
invoked by functions as they are defined. Given that this
locate-and-remember process is optional elsewhere, it seems safe enough to
make this option do nothing.
POSIX does not specify a long name for this option. Follow ksh in calling it
"trackall".
Replacing ;; with the new control operator ;& will cause the next list to be
executed as well without checking its pattern, continuing until a list ends
with ;; or until the end of the case statement. This is like omitting
"break" in a C "switch" statement.
The sequence ;& was formerly invalid.
This feature is proposed for the next POSIX issue in Austin Group issue
#449.
In optimized command substitution, save and restore any variables changed by
expansions (${var=value} and $((var=assigned))), instead of trying to
determine if an expansion may cause such changes.
If $! is referenced in optimized command substitution, do not cause jobs to
be remembered longer.
This fixes $(jobs $!) again, simplifies the man page and shortens the code.
The function name expandstr() and the general idea of doing this kind of
expansion by treating the text as a here document without end marker is from
dash.
All variants of parameter expansion and arithmetic expansion also work (the
latter is not required by POSIX but it does not take extra code and many
other shells also allow it).
Command substitution is prevented because I think it causes too much code to
be re-entered (for example creating an unbounded recursion of trace lines).
Unfortunately, our LINENO is somewhat crude, otherwise PS4='$LINENO+ ' would
be quite useful.
