 @@ -1,14 +1,14 @@
-.\"	$NetBSD: sh.1,v 1.119 2016/02/24 15:28:36 wiz Exp $
+.\"	$NetBSD: sh.1,v 1.120 2016/03/31 16:18:22 christos Exp $
 .\" Copyright (c) 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
 .\" This code is derived from software contributed to Berkeley by
 .\" Kenneth Almquist.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 @@ -21,27 +21,27 @@
 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
 .\"	@(#)sh.1	8.6 (Berkeley) 5/4/95
 .\"
-.Dd January 5, 2015
+.Dd March 31, 2016
 .Dt SH 1
 .ds flags abCEeFfhnuvxIimpqV
 .Os
 .Sh NAME
 .Nm sh
 .Nd command interpreter (shell)
 .Sh SYNOPSIS
 .Nm
 .Bk -words
 .Op Fl \*[flags]
 .Op Cm +\*[flags]
 .Ek
 .Bk -words
 @@ -320,48 +320,66 @@ instead of attempting
 .Xr vfork 2
 when it needs to create a new process.
 This should normally have no visible effect,
 but can slow execution.
 The
 .Nm
 can be compiled to always use
 .Xr fork 2
 in which case altering the
 .Fl F
 flag has no effect.
 .It Fl h Em trackall
 Bind commands in functions to file system paths when the function is defined.
 .\" They can seek me here (that dreaded filesystem)
 When off,
 the file system is searched for commands each time the function is invoked.
 (Not implemented.)
 .\" then can seek me there (the filesystem, once again)
 .It Fl p Em nopriv
 Do not attempt to reset effective uid if it does not match uid.
 This is not set by default to help avoid incorrect usage by setuid
 root programs via
 .Xr system 3
 or
 .Xr popen 3 .
 .It "\ \ " Em cdprint
 Make an interactive shell always print the new directory name when
 changed by the
 .Ic cd
 command.
 .It "\ \ " Em nolog
 Prevent the entry of function definitions into the command history (see
 .Ic fc
 in the
 .Sx Built-ins
 section.)
 (Not implemented.)
 .It "\ \ " Em posix
 Enables closer adherence to the shell standard.
 This option will default set at shell startup if the
 environment variable
 .Ev POSIXLY_CORRECT
 is present.
 That can be overridden by the
 .Fl o
 option on the command line.
 Currently this option controls whether (!posix) or not (posix)
 the file given by the
 .Ev ENV
 variable is read at startup by a non-interactive shell.
 Consequently, while it can be manipulated by the
 .Ic set
 command, doing so has no current purpose.
 .It "\ \ " Em tabcomplete
 Enables filename completion in the command line editor.
 Typing a tab character will extend the current input word to match a
 filename.
 If more than one filename matches it is only extended to be the common prefix.
 Typing a second tab character will list all the matching names.
 One of the editing modes, either
 .Fl E
 or
 .Fl V ,
 must be enabled for this to work.
 .El
 .Ss Lexical Structure
 @@ -518,62 +536,70 @@ Close standard output (or n).
 .It [n] Ns \*[Lt]\*[Gt] file
 Open file for reading and writing on standard input (or n).
 .El
 .Pp
 The following redirection is often called a
 .Dq here-document .
 .Bl -item -offset indent
 .It
 .Li [n]\*[Lt]\*[Lt] delimiter
 .Dl here-doc-text ...
 .Li delimiter
 .El
 .Pp
-All the text on successive lines up to the delimiter, or to an EOF, is
+All the text on successive lines up to the delimiter,
 which must appear on a line by itself, with nothing other
 than an immediately following newline, is
 saved away and made available to the command on standard input, or file
 descriptor n if it is specified.
 If the delimiter as specified on the initial line is
 quoted, then the here-doc-text is treated literally; otherwise, the text is
 subjected to parameter expansion, command substitution, and arithmetic
 expansion as described in the
 .Sx Word Expansions
 section below.
 If the operator is
-.Dq \*[Lt]\*[Lt]-
+.Dq \*[Lt]\*[Lt]\(mi
 instead of
 .Dq \*[Lt]\*[Lt] ,
-then leading tabs in the here-doc-text are stripped.
+then leading tabs in all lines in the here-doc-text, including before the
 end delimiter, are stripped.
 If the delimiter is not quoted, lines in here-doc-text that end with
 an unquoted \e are joined to the following line, the \e and following
 newline are simply removed while reading the here-doc, which thus guarantees
 that neither of those lines can be the end delimiter.
 .Ss Search and Execution
 There are three types of commands: shell functions, built-in commands, and
 normal programs -- and the command is searched for (by name) in that order.
 They each are executed in a different way.
 .Pp
 When a shell function is executed, all of the shell positional parameters
 (except $0, which remains unchanged) are set to the arguments of the shell
 function.
 The variables which are explicitly placed in the environment of
 the command (by placing assignments to them before the function name) are
 made local to the function and are set to the values given.
 Then the command given in the function definition is executed.
 The positional parameters are restored to their original values
 when the command completes.
 This all occurs within the current shell.
 .Pp
 Shell built-ins are executed internally to the shell, without spawning a
 new process.
 .Pp
 Otherwise, if the command name doesn't match a function or built-in, the
 command is searched for as a normal program in the file system (as
 described in the next section).
 .\" But the damned elusive filesystem shall never be defeated!
 When a normal program is executed, the shell runs the program,
 passing the arguments and the environment to the program.
 If the program is not a normal executable file (i.e., if it does
 not begin with the "magic number" whose
 .Tn ASCII
 representation is "#!", so
 .Xr execve 2
 returns
 .Er ENOEXEC
 then) the shell will interpret the program in a subshell.
 The child shell will reinitialize itself in this case,
 so that the effect will be as if a
 new shell had been invoked to handle the ad-hoc shell script, except that
 @@ -687,33 +713,38 @@ it executes in the current shell -- but
 environment is wiped).
 .Ss Background Commands -- \*[Am]
 If a command is terminated by the control operator ampersand (\*[Am]), the
 shell executes the command asynchronously -- that is, the shell does not
 wait for the command to finish before executing the next command.
 .Pp
 The format for running a command in background is:
 .Pp
 .Dl command1 \*[Am] [command2 \*[Am] ...]
 .Pp
 If the shell is not interactive, the standard input of an asynchronous
 command is set to
 .Pa /dev/null .
 The process identifier of the most recent command started in the
 background can be obtained from the value of the special parameter
 .Dq \&!
 (see
 .Sx Special Parameters ) .
 .Ss Lists -- Generally Speaking
 A list is a sequence of zero or more commands separated by newlines,
 semicolons, or ampersands, and optionally terminated by one of these three
 characters.
 The commands in a list are executed in the order they are written.
 If command is followed by an ampersand, the shell starts the
-command and immediately proceed onto the next command; otherwise it waits
+command and immediately proceeds to the next command; otherwise it waits
 for the command to terminate before proceeding to the next one.
 .Ss Short-Circuit List Operators
 .Dq \*[Am]\*[Am]
 and
 .Dq ||
 are AND-OR list operators.
 .Dq \*[Am]\*[Am]
 executes the first command, and then executes the second command if and only
 if the exit status of the first command is zero.
 .Dq ||
 is similar, but executes the second command if and only if the exit status
 of the first command is nonzero.
 .Dq \*[Am]\*[Am]
 @@ -750,37 +781,39 @@ The syntax of the while command is
 while list
 do   list
 done
 .Ed
 .Pp
 The two lists are executed repeatedly while the exit status of the
 first list is zero.
 The until command is similar, but has the word
 until in place of while, which causes it to
 repeat until the exit status of the first list is zero.
 .Pp
 The syntax of the for command is
 .Bd -literal -offset indent
-for variable in word ...
+for variable [ in word ... ]
 do   list
 done
 .Ed
 .Pp
-The words are expanded, and then the list is executed repeatedly with the
+The words are expanded, or "$@" if no words are given,
 and then the list is executed repeatedly with the
 variable set to each word in turn.
 do and done may be replaced with
 .Dq {
 and
-.Dq } .
+.Dq } ,
 but doing so is non-standard and not recommended.
 .Pp
 The syntax of the break and continue command is
 .Bd -literal -offset indent
 break [ num ]
 continue [ num ]
 .Ed
 .Pp
 Break terminates the num innermost for or while loops.
 Continue continues with the next iteration of the innermost loop.
 These are implemented as built-in commands.
 .Pp
 The syntax of the case command is
 .Bd -literal -offset indent
 @@ -811,88 +844,178 @@ Grouping commands together this way allo
 their output as though they were one program:
 .Bd -literal -offset indent
 { echo -n \*q hello \*q ; echo \*q world" ; } \*[Gt] greeting
 .Ed
 .Pp
 Note that
 .Dq }
 must follow a control operator (here,
 .Dq \&; )
 so that it is recognized as a reserved word and not as another command argument.
 .Ss Functions
 The syntax of a function definition is
 .Pp
-.Dl name ( ) command
+.Dl name ( ) command [ redirect... ]
 .Pp
 A function definition is an executable statement; when executed it
 installs a function named name and returns an exit status of zero.
 The command is normally a list enclosed between
 .Dq {
 and
 .Dq } .
 The standard syntax also allows the command to be any of the other
 compound commands, or a sub-shell, all of which are supported.
 As an extension, this shell also allows a simple command to be
 used, though users should be aware this is non-standard syntax.
 This means that
 .Dl l() ls "$@"
 works to make
 .Dq l
 an alternative name for the
 .Ic ls
 command.
 .Pp
 If the optional redirect, (see
 .Sx Redirections ) ,
 which may be of any of the normal forms,
 is given, it is applied each time the
 function is called.
 This means that a simple
 .Dq "Hello World
 function might be written (in the extended syntax) as:
 .Dl hello() cat <<EOF
 .Dl Hello World!
 .Dl EOF
 To be correctly standards conforming this should be re-written as:
 .Dl hello() { cat; } <<EOF
 .Dl Hello World!
 .Dl EOF
 Note the distinction between those forms, and
 .Dl hello() { cat <<EOF
 .Dl Hello World!
 .Dl EOF
 .Dl \&}
 which reads and processes the
 .Ic "here document
 each time the shell executes the function, and which applies
 that input only to the cat command, not to any other commands
 that might appear in the function.
 .Pp
 Variables may be declared to be local to a function by using a local
 command.
 This should appear as the first statement of a function, and the syntax is
 .Pp
 .Dl local [ variable | - ] ...
 .Pp
-.Dq Local
+.Dq Ic local
 is implemented as a built-in command.
 .Pp
-When a variable is made local, it inherits the initial value and exported
+When a variable is made local, it inherits the initial value and exported,
 unexportable,
 and read-only flags from the variable with the same name in the surrounding
 scope, if there is one.
 Otherwise, the variable is initially unset.
 Making a read-only variable local is possible, but pointless.
 If the
 .Ic readonly
 command is applied to a variable that has been declared local,
 the variable cannot be (further) modified within the function,
 or any other functions it calls, however when the function returns,
 the previous status (and value) of the variable is returned.
 .Pp
 Values may be given to local variables on the
 .Ic local
 command line in a similar fashion as used for
 .Ic export
 and
 .Ic readonly .
 .Pp
 The shell uses dynamic scoping, so that if you make the variable x local to
 function f, which then calls function g, references to the variable x made
 inside g will refer to the variable x declared inside f, not to the global
 variable named x.
 .Pp
 Note that the parameters $1, $2, ... (see
 .Sx Positional Parameters ) ,
 and $#, $* and $@ (see
 .Sx Special Parameters ) ,
 are always made local in all functions, and are reset inside the
 function to represent the options and arguments passed to the function.
 Note that $0 however retains the value it had outside the function,
 as do all the other special parameters.
 .Pp
 The only special parameter that can be made local is
 .Dq - .
 Making
 .Dq -
 local causes any shell options that are changed via the set command inside the
 function to be restored to their original values when the function
 returns.
 .Pp
 It is a syntax error to use
 .Ic local
 outside the scope of a function definition.
 When used inside a function, it exits with status 0.
 .Pp
 The syntax of the return command is
 .Pp
 .Dl return [ exitstatus ]
 .Pp
-It terminates the currently executing function.
+It terminates the currently executing function or
 .Dq \&.
 script.
 Return is implemented as a built-in command.
 The exit status of the function (or
 .Dl \&.
 command) is either that given on the
 .Ic return
 command line, or the value of the special parameter
 .Dq $?
 immediately before the return was executed.
 .Ss Variables and Parameters
 The shell maintains a set of parameters.
 A parameter denoted by a name is called a variable.
 When starting up, the shell turns all the environment
 variables into shell variables.
 New variables can be set using the form
 .Pp
 .Dl name=value
 .Pp
 Variables set by the user must have a name consisting solely of
 alphabetics, numerics, and underscores - the first of which must not be
 numeric.
 A parameter can also be denoted by a number or a special
 character as explained below.
 .Ss Positional Parameters
 A positional parameter is a parameter denoted by a number (n \*[Gt] 0).
 The shell sets these initially to the values of its command line arguments
 that follow the name of the shell script.
 The
 .Ic set
-built-in can also be used to set or reset them.
+built-in can also be used to set or reset them, and
 .Ic shift
 can be used to manipulate the list.
 .Pp
 To refer to the 10th (and later) positional parameters,
 the form ${n} must be used.
 Without the braces, a digit following
 .Dq $
 can only refer to one of the first 9 positional parameters,
 or the special parameter
 .Dq 0 .
 The word
 .Dq $10
 is treated identically to
 .Dq ${1}0 .
 .Ss Special Parameters
 A special parameter is a parameter denoted by one of the following special
 characters.
 The value of the parameter is listed next to its character.
 .Bl -tag -width thinhyphena
 .It *
 Expands to the positional parameters, starting from one.
 When the
 expansion occurs within a double-quoted string it expands to a single
 field with the value of each parameter separated by the first character of
 the
 .Ev IFS
 variable, or by a
 @@ -926,26 +1049,32 @@ Expands to the number of positional para
 Expands to the exit status of the most recent pipeline.
 .It - (Hyphen.)
 Expands to the current option flags (the single-letter
 option names concatenated into a string) as specified on
 invocation, by the set built-in command, or implicitly
 by the shell.
 .It $
 Expands to the process ID of the invoked shell.
 A subshell retains the same value of $ as its parent.
 .It \&!
 Expands to the process ID of the most recent background
 command executed from the current shell.
 For a pipeline, the process ID is that of the last command in the pipeline.
 If no background commands have yet been started by the shell, then
 .Dq \&!
 will be unset.
 Once set, the value of
 .Dq \&!
 will be retained until another background command is started.
 .It 0 (Zero.)
 Expands to the name of the shell or shell script.
 .El
 .Ss Word Expansions
 This section describes the various expansions that are performed on words.
 Not all expansions are performed on every word, as explained later.
 .Pp
 Tilde expansions, parameter expansions, command substitutions, arithmetic
 expansions, and quote removals that occur within a single word expand to a
 single field.
 It is only field splitting or pathname expansion that can
 create multiple fields from a single word.
 The single exception to this
 @@ -1013,27 +1142,27 @@ If a parameter expansion occurs inside d
 Pathname expansion is not performed on the results of the expansion.
 .It
 Field splitting is not performed on the results of the
 expansion, with the exception of the special rules for @.
 .El
 .Pp
 In addition, a parameter expansion can be modified by using one of the
 following formats.
 If the
 .Dq Dv \&:
 is omitted in the following modifiers, then the expansion is applied only
 to unset parameters, not null ones.
 .Bl -tag -width aaparameterwordaaaaa
-.It ${parameter:-word}
+.It ${parameter:\(miword}
 Use Default Values.
 If parameter is unset or null, the expansion of word
 is substituted; otherwise, the value of parameter is substituted.
 .It ${parameter:=word}
 Assign Default Values.
 If parameter is unset or null, the expansion of
 word is assigned to parameter.
 In all cases, the final value of parameter is substituted.
 Only variables, not positional parameters or special
 parameters, can be assigned in this way.
 .It ${parameter:?[word]}
 Indicate Error if Null or Unset.
 If parameter is unset or null, the
 @@ -1130,44 +1259,72 @@ of the C language, and are evaluated usi
 .Ql intmax_t
 data type (this is an extension to
 .Tn POSIX ,
 which requires only
 .Ql long
 arithmetic).
 Shell variables may be referenced by name inside an arithmetic
 expression, without needing a
 .Dq \&$
 sign.
 .Ss White Space Splitting (Field Splitting)
 After parameter expansion, command substitution, and
 arithmetic expansion the shell scans the results of
-expansions and substitutions that did not occur in double quotes for
+expansions and substitutions that did not occur in double quotes,
-field splitting and multiple fields can result.
+and
 .Dq $@
 even if it did,
 for field splitting and multiple fields can result.
 .Pp
 The shell treats each character of the
 .Ev IFS
-as a delimiter and use the delimiters to split the results of parameter
+as a delimiter and uses the delimiters to split the results of parameter
 expansion and command substitution into fields.
 .Pp
 Non-whitespace characters in
 .Ev IFS
-are treated strictly as parameter terminators.
+are treated strictly as parameter separators.
 So adjacent non-whitespace
 .Ev IFS
 characters will produce empty parameters.
 On the other hand, any sequence of whitespace
 characters that occur in
 .Ev IFS
 (known as
 .Ev IFS
 whitespace)
 can occur, leading and trailing
 .Ev IFS
 whitespace, and
 .Ev IFS
 whitespace surrounding a non whitespace
 .Ev IFS
 delimiter, is removed.
 Any sequence of
 .Ev IFS
 whitespace characters without a non-whitespace
 .Ev IFS
 delimiter acts as a field separator.
 .Pp
 If
 .Ev IFS
-is unset it is assumed to contain space, tab, and newline.
+is unset it is assumed to contain space, tab, and newline,
 all of which are
 .Ev IFS
 whitespace characters.
 If
 .Ev IFS
 is set to a null string, there are no delimiters,
 and no field splitting occurs.
 .Ss Pathname Expansion (File Name Generation)
 Unless the
 .Fl f
 flag is set, file name generation is performed after word splitting is
 complete.
 Each word is viewed as a series of patterns, separated by slashes.
 The process of expansion replaces the word with the names of all
 existing files whose names can be formed by replacing each pattern with a
 string that matches the specified pattern.
 There are two restrictions on
 this: first, a pattern cannot match a string containing a slash, and
 second, a pattern cannot match a string starting with a period unless the
 first character of the pattern is a period.
 @@ -1210,94 +1367,95 @@ matches a
 .Dq \&[
 rather than introducing a character class.
 A character class matches any of the characters between the square brackets.
 A named class of characters (see
 .Xr wctype 3 )
 may be specified by surrounding the name with
 .Pq Dq [:
 and
 .Pq Dq :] .
 For example,
 .Pq Dq [[:alpha:]]
 is a shell pattern that matches a single letter.
 A range of characters may be specified using a minus sign
-.Pq Dq - .
+.Pq Dq \(mi .
 The character class may be complemented
 by making an exclamation mark
 .Pq Dq \&!
 the first character of the character class.
 .Pp
 To include a
 .Dq \&]
 in a character class, make it the first character listed (after the
 .Dq \&! ,
 if any).
 To include a
-.Dq - ,
+.Dq \(mi ,
 make it the first or last character listed.
 .Ss Built-ins
 This section lists the built-in commands which are built-in because they
 need to perform some operation that can't be performed by a separate
 process.
 In addition to these, there are several other commands that may
 be built in for efficiency (e.g.
 .Xr printf 1 ,
 .Xr echo 1 ,
 .Xr test 1 ,
 etc).
 .Bl -tag -width 5n
 .It : [ Ar arg ... ]
 A null command that returns a 0 (true) exit value.
-Any arguments are ignored.
+Any arguments or redirects are evaluated, then ignored.
 .It \&. file
 The dot command reads and executes the commands from the specified
 .Ar file
 in the current shell environment.
 The file does not need to be executable and is looked up from the directories
 listed in the
 .Ev PATH
-variable if it does not contain a directory separator
+variable if its name does not contain a directory separator
 .Pq Sq / .
 The return command can be used for a premature return from the sourced file.
 .Pp
-The POSIX standard is unclear on how loop control keywords (break
+The POSIX standard has been unclear on how loop control keywords (break
 and continue) behave across a dot command boundary.
 This implementation allows them to control loops surrounding the dot command,
 but obviously such behavior should not be relied on.
 It is now permitted by the standard, but not required.
 .It alias Op Ar name Ns Op Ar "=string ..."
 If
 .Ar name=string
 is specified, the shell defines the alias
 .Ar name
 with value
 .Ar string .
 If just
 .Ar name
 is specified, the value of the alias
 .Ar name
 is printed.
 With no arguments, the
 .Ic alias
 built-in prints the
 names and values of all defined aliases (see
 .Ic unalias ) .
 .It bg [ Ar job ] ...
 Continue the specified jobs (or the current job if no
 jobs are given) in the background.
 .It command Oo Fl p Oc Oo Fl v Oc Oo Fl V Oc Ar command Oo Ar arg ... Oc
 Execute the specified command but ignore shell functions when searching
 for it.
 (This is useful when you
-have a shell function with the same name as a built-in command.)
+have a shell function with the same name as a command.)
 .Bl -tag -width 5n
 .It Fl p
 search for command using a
 .Ev PATH
 that guarantees to find all the standard utilities.
 .It Fl V
 Do not execute the command but
 search for the command and print the resolution of the
 command search.
 This is the same as the
 .Ic type
 built-in.
 .It Fl v
 @@ -1387,40 +1545,76 @@ or
 .Dv FD_CLOEXEC ) ,
 unless the descriptors they point to refer to the standard input,
 output, or error (file descriptors 0, 1, 2).
 Traditionally Bourne-like shells
 (except
 .Xr ksh 1 ) ,
 made those file descriptors available to exec'ed processes.
 .It exit Op Ar exitstatus
 Terminate the shell process.
 If
 .Ar exitstatus
 is given it is used as the exit status of the shell; otherwise the
 exit status of the preceding command is used.
-.It export Ar name ...
+.It export Oo Fl npx Oc Ar name ...
-.It export Fl p
+.It export Fl p Oo Fl x Oc
-The specified names are exported so that they will appear in the
+With no options,
 the specified names are exported so that they will appear in the
 environment of subsequent commands.
-The only way to un-export a variable is to unset it.
+With
 .Fl n
 the specified names are un-exported.
 Variables can also be un-exported using the unset builtin command.
 With
 .Fl x
 (exclude) the specified names are marked not to be exported,
 and any that had been exported, will be un-exported.
 Later attempts to export the variable will be refused.
 Note this does not prevent explicitly exporting a variable
 to a single command, script or function by preceding that
 command invocation by a variable assignment to that variable,
 provided the variable is not also readonly.
 That is
 .Dl	export -x FOO ; # FOO will now not be exported by default
 .Dl	FOO=some_value my_command
 still passes the value (FOO=some_value) to
 .Ic my_command
 through the environment.
 .Pp
 The shell allows the value of a variable to be set at the
 same time it is exported by writing
 .Pp
 .Dl export name=value
 .Pp
-With no arguments the export command lists the names of all exported variables.
+With no arguments the export command lists the names of all exported variables,
 or if
 .Fl x
 was given, all variables marked not for export.
 With the
 .Fl p
 option specified the output will be formatted suitably for non-interactive use.
 .Pp
 The
 .Ic export
 built-in exits with status 0,
 unless an invalid option, or option combination, is given,
 or unless an attempt is made to export a variable which has
 been marked as unavailable for export,
 in which cases it exits with status 1.
 .Pp
 Note that there is no restriction upon exporting,
 or un-exporting, readonly variables.
 The no-export flag can be reset by unsetting the variable
 and creating it again \(en provided it is not also readonly.
 .It fc Oo Fl e Ar editor Oc Oo Ar first Oo Ar last Oc Oc
 .It fc Fl l Oo Fl nr Oc Oo Ar first Oo Ar last Oc Oc
 .It fc Fl s Oo Ar old=new Oc Oo Ar first Oc
 The
 .Ic fc
 built-in lists, or edits and re-executes, commands previously entered
 to an interactive shell.
 .Bl -tag -width 5n
 .It Fl e No editor
 Use the editor named by editor to edit the commands.
 The editor string is a command name, subject to search via the
 .Ev PATH
 variable.
 @@ -1750,43 +1944,45 @@ If no arguments are present, the set com
 will clear all the positional parameters (equivalent to executing
 .Dq shift $# . )
 .It setvar Ar variable Ar value
 Assigns value to variable.
 (In general it is better to write
 variable=value rather than using
 .Ic setvar .
 .Ic setvar
 is intended to be used in
 functions that assign values to variables whose names are passed as
 parameters.)
 .It shift Op Ar n
 Shift the positional parameters n times.
 If n is omitted, 1 is assumed.
 Each
 .Ic shift
 sets the value of
 .Va $1
-to the value of
+to the previous value of
 .Va $2 ,
 the value of
 .Va $2
-to the value of
+to the previous value of
 .Va $3 ,
 and so on, decreasing
 the value of
 .Va $#
 by one.
-If there are zero positional parameters,
+The shift count must be less than or equal to the number of
-.Ic shift
+positional parameters (
-does nothing.
+.Dq $# )
 before the shift.
 .It trap Oo Fl l Oc
 .It trap Oo Ar action Oc Ar signal ...
 Cause the shell to parse and execute action when any of the specified
 signals are received.
 The signals are specified by signal number or as the name of the signal.
 If
 .Ar signal
 is
 .Li 0
 or its equivalent, EXIT,
 the action is executed when the shell exits.
 .Ar action
 may be null, which cause the specified signals to be ignored.
 @@ -1820,27 +2016,29 @@ Examples:
 .Pp
 List trapped signals and their corresponding action
 .Pp
 .Dl trap -l
 .Pp
 Print a list of valid signals
 .Pp
 .Dl trap '' INT QUIT tstp 30
 .Pp
 Ignore signals INT QUIT TSTP USR1
 .Pp
 .Dl trap date INT
 .Pp
-Print date upon receiving signal INT
+Run the
 .Dq date
 command (print the date) upon receiving signal INT
 .It type Op Ar name ...
 Interpret each name as a command and print the resolution of the command
 search.
 Possible resolutions are:
 shell keyword, alias, shell built-in,
 command, tracked alias and not found.
 For aliases the alias expansion is
 printed; for commands and tracked aliases the complete pathname of the
 command is printed.
 .It ulimit Oo Fl H \*(Ba Fl S Oc Oo Fl a \*(Ba Fl btfdscmlrpnv Oo Ar value Oc Oc
 Inquire about or set the hard or soft limits on processes or set new
 limits.
 The choice between hard limit (which no process is allowed to
 @@ -1909,35 +2107,74 @@ utility.
 .Pp
 .It umask Op Ar mask
 Set the value of umask (see
 .Xr umask 2 )
 to the specified octal value.
 If the argument is omitted, the umask value is printed.
 .It unalias Oo Fl a Oc Oo Ar name Oc
 If
 .Ar name
 is specified, the shell removes that alias.
 If
 .Fl a
 is specified, all aliases are removed.
-.It unset Ar name ...
+.It unset Oo Fl efv Oc Ar name ...
-The specified variables and functions are unset and unexported.
+If
-If a given name corresponds to both a variable and a function, both
+.Fl v
-the variable and the function are unset.
+is specified, the specified variables are unset and unexported.
 Readonly variables cannot be unset.
 If
 .Fl f
 is specified, the specified functions are undefined.
 If
 .Fl e
 is given, the specified variables are unexported, but otherwise unchanged.
 .Pp
 If no flags are provided
 .Fl v
 is assumed.
 If
 .Fl f
 is given with one (or both) of
 .Fl v
 or
 .Fl e ,
 then the named variables will be unset, or unexported, and functions
 of the same names will be undefined.
 It makes no sense to give both
 .Fl v
 and
 .Fl e
 as unsetting a variable unexports it as well.
 However doing so is not an error, the last specified is used.
 The exit status is 0, unless an attempt was made to unset
 a readonly variable, in which case the exit status is 1.
 It is not an error to unset (or undefine) a variable (or function)
 that is not currently set (or defined.)
 .It wait Op Ar job
 Wait for the specified job to complete and return the exit status of the
-last process in the job.
+last process in the job, or 127 if the job is not a current child of
 the shell.
 If the argument is omitted, wait for all jobs to
 complete and then return an exit status of zero.
 If the wait is interrupted by a signal,
 its exit status will be greater than 128.
 .Pp
 Once waited upon, by specific process number or job-id,
 or by a
 .Ic wait
 with no argumentss,
 knowledge of the child is removed from the system,
 and it cannot be waited upon again.
 .El
 .Ss Command Line Editing
 When
 .Nm
 is being used interactively from a terminal, the current command
 and the command history (see
 .Ic fc
 in the
 .Sx Built-ins
 section)
 can be edited using emacs-mode or vi-mode command-line editing.
 The command
 .Ql set -o emacs
 @@ -1974,98 +2211,110 @@ The
 mode uses commands similar to a subset available in
 the
 .Xr emacs 1
 editor.
 With emacs-mode enabled, special keys can be used to modify the text
 in the buffer using the control key.
 .Pp
 .Nm
 uses the
 .Xr editline 3
 library.
 .Sh ENVIRONMENT
 .Bl -tag -width MAILCHECK
 .It Ev CDPATH
 The search path used with the
 .Ic cd
 built-in.
 .It Ev HISTSIZE
 The number of lines in the history buffer for the shell.
 .It Ev HOME
 Set automatically by
 .Xr login 1
 from the user's login directory in the password file
 .Pq Xr passwd 5 .
 This environment variable also functions as the default argument for the
 .Ic cd
 built-in.
-.It Ev PATH
+.It Ev IFS
-The default search path for executables.
+Input Field Separators.
 This is normally set to
 .Aq space ,
 .Aq tab ,
 and
 .Aq newline .
 See the
-.Sx Path Search
+.Sx White Space Splitting
-section above.
+section for more details.
 .It Ev CDPATH
 The search path used with the
 .Ic cd
 built-in.
 .It Ev LINENO
 The current line number in the script or function.
 .It Ev LANG
 The string used to specify localization information that allows users
 to work with different culture-specific and language conventions.
 See
 .Xr nls 7 .
 .It Ev LINENO
 The current line number in the script or function.
 .It Ev MAIL
 The name of a mail file, that will be checked for the arrival of new mail.
 Overridden by
 .Ev MAILPATH .
 .It Ev MAILCHECK
 The frequency in seconds that the shell checks for the arrival of mail
 in the files specified by the
 .Ev MAILPATH
 or the
 .Ev MAIL
 file.
 If set to 0, the check will occur at each prompt.
 .It Ev MAILPATH
 A colon
 .Dq \&:
 separated list of file names, for the shell to check for incoming mail.
 This environment setting overrides the
 .Ev MAIL
 setting.
 There is a maximum of 10 mailboxes that can be monitored at once.
 .It Ev PATH
 The default search path for executables.
 See the
 .Sx Path Search
 section above.
 .It Ev PS1
 The primary prompt string, which defaults to
 .Dq $ \  ,
 unless you are the superuser, in which case it defaults to
 .Dq # \  .
 .It Ev PS2
 The secondary prompt string, which defaults to
 .Dq \*[Gt] \  .
 .It Ev PS4
 Output before each line when execution trace (set -x) is enabled,
 defaults to
 .Dq + \  .
 .It Ev IFS
 Input Field Separators.
 This is normally set to
 .Aq space ,
 .Aq tab ,
 and
 .Aq newline .
 See the
 .Sx White Space Splitting
 section for more details.
 .It Ev TERM
 The default terminal setting for the shell.
 This is inherited by
 children of the shell, and is used in the history editing modes.
-.It Ev HISTSIZE
+.\" This is explicitly last, not in sort order - please leave!
-The number of lines in the history buffer for the shell.
+.It Ev NETBSD_SHELL
 Unlike the variables mentioned above,
 this variable is somewhat strange,
 in that it cannot be set,
 inherited from the environment,
 modified, or exported from the shell.
 If set, it indicates that the shell is the
 .Ic sh
 defined by this manual page, and gives its version information.
 It behaves like any other variable that has the read-only
 and un-exportable attributes set.
 .El
 .Sh FILES
 .Bl -item
 .It
 .Pa $HOME/.profile
 .It
 .Pa /etc/profile
 .El
 .Sh EXIT STATUS
 Errors that are detected by the shell, such as a syntax error, will cause the
 shell to exit with a non-zero exit status.
 If the shell is not an
 interactive shell, the execution of the shell file will be aborted.
 @@ -2095,13 +2344,15 @@ A
 command appeared in
 .At v1 .
 It was, however, unmaintainable so we wrote this one.
 .Sh BUGS
 Setuid shell scripts should be avoided at all costs, as they are a
 significant security risk.
 .Pp
 PS1, PS2, and PS4 should be subject to parameter expansion before
 being displayed.
 .Pp
 The characters generated by filename completion should probably be quoted
 to ensure that the filename is still valid after the input line has been
 processed.
 .Pp
 Many, many, more.