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ZSHMISC(1)              FreeBSD General Commands Manual             ZSHMISC(1)

NAME
       zshmisc - everything and then some

SIMPLE COMMANDS & PIPELINES
       A simple command is a sequence of optional parameter assignments
       followed by blank-separated words, with optional redirections
       interspersed.  The first word is the command to be executed, and the
       remaining words, if any, are arguments to the command.  If a command
       name is given, the parameter assignments modify the environment of the
       command when it is executed.  The value of a simple command is its exit
       status, or 128 plus the signal number if terminated by a signal.  For
       example,

              echo foo

       is a simple command with arguments.

       A pipeline is either a simple command, or a sequence of two or more
       simple commands where each command is separated from the next by `|' or
       `|&'.  Where commands are separated by `|', the standard output of the
       first command is connected to the standard input of the next.  `|&' is
       shorthand for `2>&1 |', which connects both the standard output and the
       standard error of the command to the standard input of the next.  The
       value of a pipeline is the value of the last command, unless the
       pipeline is preceded by `!' in which case the value is the logical
       inverse of the value of the last command.  For example,

              echo foo | sed 's/foo/bar/'

       is a pipeline, where the output (`foo' plus a newline) of the first
       command will be passed to the input of the second.

       If a pipeline is preceded by `coproc', it is executed as a coprocess; a
       two-way pipe is established between it and the parent shell.  The shell
       can read from or write to the coprocess by means of the `>&p' and `<&p'
       redirection operators or with `print -p' and `read -p'.  A pipeline
       cannot be preceded by both `coproc' and `!'.  If job control is active,
       the coprocess can be treated in other than input and output as an
       ordinary background job.

       A sublist is either a single pipeline, or a sequence of two or more
       pipelines separated by `&&' or `||'.  If two pipelines are separated by
       `&&', the second pipeline is executed only if the first succeeds
       (returns a zero value).  If two pipelines are separated by `||', the
       second is executed only if the first fails (returns a nonzero value).
       Both operators have equal precedence and are left associative.  The
       value of the sublist is the value of the last pipeline executed.  For
       example,

              dmesg | grep panic && print yes

       is a sublist consisting of two pipelines, the second just a simple
       command which will be executed if and only if the grep command returns
       a zero value.  If it does not, the value of the sublist is that return
       value, else it is the value returned by the print (almost certainly
       zero).

       A list is a sequence of zero or more sublists, in which each sublist is
       terminated by `;', `&', `&|', `&!', or a newline.  This terminator may
       optionally be omitted from the last sublist in the list when the list
       appears as a complex command inside `(...)' or `{...}'.  When a sublist
       is terminated by `;' or newline, the shell waits for it to finish
       before executing the next sublist.  If a sublist is terminated by a
       `&', `&|', or `&!', the shell executes the last pipeline in it in the
       background, and does not wait for it to finish (note the difference
       from other shells which execute the whole sublist in the background).
       A backgrounded pipeline returns a status of zero.

       More generally, a list can be seen as a set of any shell commands
       whatsoever, including the complex commands below; this is implied
       wherever the word `list' appears in later descriptions.  For example,
       the commands in a shell function form a special sort of list.

PRECOMMAND MODIFIERS
       A simple command may be preceded by a precommand modifier, which will
       alter how the command is interpreted.  These modifiers are shell
       builtin commands with the exception of nocorrect which is a reserved
       word.

       -      The command is executed with a `-' prepended to its argv[0]
              string.

       noglob Filename generation (globbing) is not performed on any of the
              words.

       nocorrect
              Spelling correction is not done on any of the words.  This must
              appear before any other precommand modifier, as it is
              interpreted immediately, before any parsing is done.  It has no
              effect in non-interactive shells.

       exec   The command is executed in the parent shell without forking.

       command
              The command word is taken to be the name of an external command,
              rather than a shell function or builtin.

       builtin
              The command word is taken to be the name of a builtin command,
              rather than a shell function or external command.

COMPLEX COMMANDS
       A complex command in zsh is one of the following:

       if list then list [ elif list then list ] ... [ else list ] fi
              The if list is executed, and if it returns a zero exit status,
              the then list is executed.  Otherwise, the elif list is executed
              and if its value is zero, the then list is executed.  If each
              elif list returns nonzero, the else list is executed.

       for name [ in word ... term ] do list done
              where term is at least one newline or ;.  Expand the list of
              words, and set the parameter name to each of them in turn,
              executing list each time.  If the in word is omitted, use the
              positional parameters instead of the words.

       for (( [expr1] ; [expr2] ; [expr3] )) do list done
              The arithmetic expression expr1 is evaluated first (see the
              section `Arithmetic Evaluation').  The arithmetic expression
              expr2 is repeatedly evaluated until it evaluates to zero and
              when non-zero, list is executed and the arithmetic expression
              expr3 evaluated.  If any expression is omitted, then it behaves
              as if it evaluated to 1.

       while list do list done
              Execute the do list as long as the while list returns a zero
              exit status.

       until list do list done
              Execute the do list as long as until list returns a nonzero exit
              status.

       repeat word do list done
              word is expanded and treated as an arithmetic expression, which
              must evaluate to a number n.  list is then executed n times.

       case word in [ [(] pattern [ | pattern ] ... ) list (;;|;&) ] ... esac
              Execute the list associated with the first pattern that matches
              word, if any.  The form of the patterns is the same as that used
              for filename generation.  See the section `Filename Generation'.
              If the list that is executed is terminated with ;& rather than
              ;;, the following list is also executed.  This continues until
              either a list is terminated with ;; or the esac is reached.

       select name [ in word ... term ] do list done
              where term is one or more newline or ; to terminate the words.
              Print the set of words, each preceded by a number.  If the in
              word is omitted, use the positional parameters.  The PROMPT3
              prompt is printed and a line is read from the line editor if the
              shell is interactive and that is active, or else standard input.
              If this line consists of the number of one of the listed words,
              then the parameter name is set to the word corresponding to this
              number.  If this line is empty, the selection list is printed
              again.  Otherwise, the value of the parameter name is set to
              null.  The contents of the line read from standard input is
              saved in the parameter REPLY.  list is executed for each
              selection until a break or end-of-file is encountered.

       ( list )
              Execute list in a subshell.  Traps set by the trap builtin are
              reset to their default values while executing list.

       { list }
              Execute list.

       function word ... [ () ] [ term ] { list }
       word ... () [ term ] { list }
       word ... () [ term ] command
              where term is one or more newline or ;.  Define a function which
              is referenced by any one of word.  Normally, only one word is
              provided; multiple words are usually only useful for setting
              traps.  The body of the function is the list between the { and
              }.  See the section `Functions'.

              If the option SH_GLOB is set for compatibility with other
              shells, then whitespace may appear between between the left and
              right parentheses when there is a single word;  otherwise, the
              parentheses will be treated as forming a globbing pattern in
              that case.

       time [ pipeline ]
              The pipeline is executed, and timing statistics are reported on
              the standard error in the form specified by the TIMEFMT
              parameter.  If pipeline is omitted, print statistics about the
              shell process and its children.

       [[ exp ]]
              Evaluates the conditional expression exp and return a zero exit
              status if it is true.  See the section `Conditional Expressions'
              for a description of exp.

ALTERNATE FORMS FOR COMPLEX COMMANDS
       Many of zsh's complex commands have alternate forms.  These particular
       versions of complex commands should be considered deprecated and may be
       removed in the future.  The versions in the previous section should be
       preferred instead.

       The short versions below only work if sublist is of the form `{ list }'
       or if the SHORT_LOOPS option is set.  For the if, while and until
       commands, in both these cases the test part of the loop must also be
       suitably delimited, such as by `[[ ... ]]' or `(( ... ))', else the end
       of the test will not be recognized.  For the for, repeat, case and
       select commands no such special form for the arguments is necessary,
       but the other condition (the special form of sublist or use of the
       SHORT_LOOPS option) still applies.

       if list { list } [ elif list { list } ] ... [ else { list } ]
              An alternate form of if.  The rules mean that

                     if [[ -o ignorebraces ]] {
                       print yes
                     }

              works, but

                     if true {  # Does not work!
                       print yes
                     }

              does not, since the test is not suitably delimited.

       if list sublist
              A short form of the alternate `if'.  The same limitations on the
              form of list apply as for the previous form.

       for name ( word ... ) sublist
              A short form of for.

       for name [ in word ... term ] sublist
              where term is at least one newline or ;.  Another short form of
              for.

       for (( [expr1] ; [expr2] ; [expr3] )) sublist
              A short form of the arithmetic for command.

       foreach name ( word ... ) list end
              Another form of for.

       while list { list }
              An alternative form of while.  Note the limitations on the form
              of list mentioned above.

       until list { list }
              An alternative form of until.  Note the limitations on the form
              of list mentioned above.

       repeat word sublist
              This is a short form of repeat.

       case word { [ [(] pattern [ | pattern ] ... ) list (;;|;&) ] ... }
              An alternative form of case.

       select name [ in word term ] sublist
              where term is at least one newline or ;.  A short form of
              select.

RESERVED WORDS
       The following words are recognized as reserved words when used as the
       first word of a command unless quoted or disabled using disable -r:

       do done esac then elif else fi for case if while function repeat time
       until select coproc nocorrect foreach end ! [[ { }

       Additionally, `}' is recognized in any position if the IGNORE_BRACES
       option is not set.

COMMENTS
       In noninteractive shells, or in interactive shells with the
       INTERACTIVE_COMMENTS option set, a word beginning with the third
       character of the histchars parameter (`#' by default) causes that word
       and all the following characters up to a newline to be ignored.

ALIASING
       Every token in the shell input is checked to see if there is an alias
       defined for it.  If so, it is replaced by the text of the alias if it
       is in command position (if it could be the first word of a simple
       command), or if the alias is global.  If the text ends with a space,
       the next word in the shell input is treated as though it were in
       command position for purposes of alias expansion.  An alias is defined
       using the alias builtin; global aliases may be defined using the -g
       option to that builtin.

       Alias expansion is done on the shell input before any other expansion
       except history expansion.  Therefore, if an alias is defined for the
       word foo, alias expansion may be avoided by quoting part of the word,
       e.g. \foo.  But there is nothing to prevent an alias being defined for
       \foo as well.

QUOTING
       A character may be quoted (that is, made to stand for itself) by
       preceding it with a `\'.  `\' followed by a newline is ignored.

       A string enclosed between `$'' and `'' is processed the same way as the
       string arguments of the print builtin, and the resulting string is
       considered to be entirely quoted.  A literal `'' character can be
       included in the string by using the `\'' escape.

       All characters enclosed between a pair of single quotes ('') that is
       not preceded by a `$' are quoted.  A single quote cannot appear within
       single quotes unless the option RC_QUOTES is set, in which case a pair
       of single quotes are turned into a single quote.  For example,

              print ''''

       outputs nothing apart from a newline if RC_QUOTES is not set, but one
       single quote if it is set.

       Inside double quotes (""), parameter and command substitution occur,
       and `\' quotes the characters `\', ``', `"', and `$'.

REDIRECTION
       If a command is followed by & and job control is not active, then the
       default standard input for the command is the empty file /dev/null.
       Otherwise, the environment for the execution of a command contains the
       file descriptors of the invoking shell as modified by input/output
       specifications.

       The following may appear anywhere in a simple command or may precede or
       follow a complex command.  Expansion occurs before word or digit is
       used except as noted below.  If the result of substitution on word
       produces more than one filename, redirection occurs for each separate
       filename in turn.

       < word Open file word for reading as standard input.

       <> word
              Open file word for reading and writing as standard input.  If
              the file does not exist then it is created.

       > word Open file word for writing as standard output.  If the file does
              not exist then it is created.  If the file exists, and the
              CLOBBER option is unset, this causes an error; otherwise, it is
              truncated to zero length.

       >| word
       >! word
              Same as >, except that the file is truncated to zero length if
              it exists, even if CLOBBER is unset.

       >> word
              Open file word for writing in append mode as standard output.
              If the file does not exist, and the CLOBBER option is unset,
              this causes an error; otherwise, the file is created.

       >>| word
       >>! word
              Same as >>, except that the file is created if it does not
              exist, even if CLOBBER is unset.

       <<[-] word
              The shell input is read up to a line that is the same as word,
              or to an end-of-file.  No parameter expansion, command
              substitution or filename generation is performed on word.  The
              resulting document, called a here-document, becomes the standard
              input.

              If any character of word is quoted with single or double quotes
              or a `\', no interpretation is placed upon the characters of the
              document.  Otherwise, parameter and command substitution occurs,
              `\' followed by a newline is removed, and `\' must be used to
              quote the characters `\', `$', ``' and the first character of
              word.

              If <<- is used, then all leading tabs are stripped from word and
              from the document.

       <<< word
              Perform shell expansion on word and pass the result to standard
              input.  This is known as a here-string.

       <& number
       >& number
              The standard input/output is duplicated from file descriptor
              number (see dup2(2)).

       <& -
       >& -   Close the standard input/output.

       <& p
       >& p   The input/output from/to the coprocess is moved to the standard
              input/output.

       >& word
       &> word
              (Except where `>& word' matches one of the above syntaxes; `&>'
              can always be used to avoid this ambiguity.) Redirects both
              standard output and standard error (file descriptor 2) in the
              manner of `> word'.  Note that this does not have the same
              effect as `> word 2>&1' in the presence of multios (see the
              section below).

       >&| word
       >&! word
       &>| word
       &>! word
              Redirects both standard output and standard error (file
              descriptor 2) in the manner of `>| word'.

       >>& word
       &>> word
              Redirects both standard output and standard error (file
              descriptor 2) in the manner of `>> word'.

       >>&| word
       >>&! word
       &>>| word
       &>>! word
              Redirects both standard output and standard error (file
              descriptor 2) in the manner of `>>| word'.

       If one of the above is preceded by a digit, then the file descriptor
       referred to is that specified by the digit instead of the default 0 or
       1.  The order in which redirections are specified is significant.  The
       shell evaluates each redirection in terms of the (file descriptor,
       file) association at the time of evaluation.  For example:

              ... 1>fname 2>&1

       first associates file descriptor 1 with file fname.  It then associates
       file descriptor 2 with the file associated with file descriptor 1 (that
       is, fname).  If the order of redirections were reversed, file
       descriptor 2 would be associated with the terminal (assuming file
       descriptor 1 had been) and then file descriptor 1 would be associated
       with file fname.

MULTIOS
       If the user tries to open a file descriptor for writing more than once,
       the shell opens the file descriptor as a pipe to a process that copies
       its input to all the specified outputs, similar to tee, provided the
       MULTIOS option is set, as it is by default.  Thus:

              date >foo >bar

       writes the date to two files, named `foo' and `bar'.  Note that a pipe
       is an implicit redirection; thus

              date >foo | cat

       writes the date to the file `foo', and also pipes it to cat.

       If the MULTIOS option is set, the word after a redirection operator is
       also subjected to filename generation (globbing).  Thus

              : > *

       will truncate all files in the current directory, assuming there's at
       least one.  (Without the MULTIOS option, it would create an empty file
       called `*'.) Similarly, you can do

              echo exit 0 >> *.sh

       If the user tries to open a file descriptor for reading more than once,
       the shell opens the file descriptor as a pipe to a process that copies
       all the specified inputs to its output in the order specified, similar
       to cat, provided the MULTIOS option is set.  Thus

              sort <foo <fubar

       or even

              sort <f{oo,ubar}

       is equivalent to `cat foo fubar | sort'.

       Note that a pipe is an implicit redirection; thus

              cat bar | sort <foo

       is equivalent to `cat bar foo | sort' (note the order of the inputs).

       If the MULTIOS option is unset, each redirection replaces the previous
       redirection for that file descriptor.  However, all files redirected to
       are actually opened, so

              echo foo > bar > baz

       when MULTIOS is unset will truncate bar, and write `foo' into baz.

REDIRECTIONS WITH NO COMMAND
       When a simple command consists of one or more redirection operators and
       zero or more parameter assignments, but no command name, zsh can behave
       in several ways.

       If the parameter NULLCMD is not set or the option CSH_NULLCMD is set,
       an error is caused.  This is the csh behavior and CSH_NULLCMD is set by
       default when emulating csh.

       If the option SH_NULLCMD is set, the builtin `:' is inserted as a
       command with the given redirections.  This is the default when
       emulating sh or ksh.

       Otherwise, if the parameter NULLCMD is set, its value will be used as a
       command with the given redirections.  If both NULLCMD and READNULLCMD
       are set, then the value of the latter will be used instead of that of
       the former when the redirection is an input.  The default for NULLCMD
       is `cat' and for READNULLCMD is `more'. Thus

              < file

       shows the contents of file on standard output, with paging if that is a
       terminal.  NULLCMD and READNULLCMD may refer to shell functions.

COMMAND EXECUTION
       If a command name contains no slashes, the shell attempts to locate it.
       If there exists a shell function by that name, the function is invoked
       as described in the section `Functions'.  If there exists a shell
       builtin by that name, the builtin is invoked.

       Otherwise, the shell searches each element of $path for a directory
       containing an executable file by that name.  If the search is
       unsuccessful, the shell prints an error message and returns a nonzero
       exit status.

       If execution fails because the file is not in executable format, and
       the file is not a directory, it is assumed to be a shell script.
       /bin/sh is spawned to execute it.  If the program is a file beginning
       with `#!', the remainder of the first line specifies an interpreter for
       the program.  The shell will execute the specified interpreter on
       operating systems that do not handle this executable format in the
       kernel.

FUNCTIONS
       Shell functions are defined with the function reserved word or the
       special syntax `funcname ()'.  Shell functions are read in and stored
       internally.  Alias names are resolved when the function is read.
       Functions are executed like commands with the arguments passed as
       positional parameters.  (See the section `Command Execution'.)

       Functions execute in the same process as the caller and share all files
       and present working directory with the caller.  A trap on EXIT set
       inside a function is executed after the function completes in the
       environment of the caller.

       The return builtin is used to return from function calls.

       Function identifiers can be listed with the functions builtin.
       Functions can be undefined with the unfunction builtin.

AUTOLOADING FUNCTIONS
       A function can be marked as undefined using the autoload builtin (or
       `functions -u' or `typeset -fu').  Such a function has no body.  When
       the function is first executed, the shell searches for its definition
       using the elements of the fpath variable.  Thus to define functions for
       autoloading, a typical sequence is:

              fpath=(~/myfuncs $fpath)
              autoload myfunc1 myfunc2 ...

       The usual alias expansion during reading will be suppressed if the
       autoload builtin or its equivalent is given the option -U. This is
       recommended for the use of functions supplied with the zsh
       distribution.  Note that for functions precompiled with the zcompile
       builtin command the flag -U must be provided when the .zwc file is
       created, as the corresponding information is compiled into the latter.

       For each element in fpath, the shell looks for three possible files,
       the newest of which is used to load the definition for the function:

       element.zwc
              A file created with the zcompile builtin command, which is
              expected to contain the definitions for all functions in the
              directory named element.  The file is treated in the same manner
              as a directory containing files for functions and is searched
              for the definition of the function.   If the definition is not
              found, the search for a definition proceeds with the other two
              possibilities described below.

              If element already includes a .zwc extension (i.e. the extension
              was explicitly given by the user), element is searched for the
              definition of the function without comparing its age to that of
              other files; in fact, there does not need to be any directory
              named element without the suffix.  Thus including an element
              such as `/usr/local/funcs.zwc' in fpath will speed up the search
              for functions, with the disadvantage that functions included
              must be explicitly recompiled by hand before the shell notices
              any changes.

       element/function.zwc
              A file created with zcompile, which is expected to contain the
              definition for function.  It may include other function
              definitions as well, but those are neither loaded nor executed;
              a file found in this way is searched only for the definition of
              function.

       element/function
              A file of zsh command text, taken to be the definition for
              function.

       In summary, the order of searching is, first, in the parents of
       directories in fpath for the newer of either a compiled directory or a
       directory in fpath; second, if more than one of these contains a
       definition for the function that is sought, the leftmost in the fpath
       is chosen; and third, within a directory, the newer of either a
       compiled function or an ordinary function definition is used.

       If the KSH_AUTOLOAD option is set, or the file contains only a simple
       definition of the function, the file's contents will be executed.  This
       will normally define the function in question, but may also perform
       initialization, which is executed in the context of the function
       execution, and may therefore define local parameters.  It is an error
       if the function is not defined by loading the file.

       Otherwise, the function body (with no surrounding `funcname() {...}')
       is taken to be the complete contents of the file.  This form allows the
       file to be used directly as an executable shell script.  If processing
       of the file results in the function being re-defined, the function
       itself is not re-executed.  To force the shell to perform
       initialization and then call the function defined, the file should
       contain initialization code (which will be executed then discarded) in
       addition to a complete function definition (which will be retained for
       subsequent calls to the function), and a call to the shell function,
       including any arguments, at the end.

       For example, suppose the autoload file func contains

              func() { print This is func; }
              print func is initialized

       then `func; func' with KSH_AUTOLOAD set will produce both messages on
       the first call, but only the message `This is func' on the second and
       subsequent calls.  Without KSH_AUTOLOAD set, it will produce the
       initialization message on the first call, and the other message on the
       second and subsequent calls.

       It is also possible to create a function that is not marked as
       autoloaded, but which loads its own definition by searching fpath, by
       using `autoload -X' within a shell function.  For example, the
       following are equivalent:

              myfunc() {
                autoload -X
              }
              myfunc args...

       and

              unfunction myfunc   # if myfunc was defined
              autoload myfunc
              myfunc args...

       In fact, the functions command outputs `builtin autoload -X' as the
       body of an autoloaded function.  A true autoloaded function can be
       identified by the presence of the comment `# undefined' in the body,
       because all comments are discarded from defined functions.  This is
       done so that

              eval "$(functions)"

       produces a reasonable result.

       To load the definition of an autoloaded function myfunc without
       executing myfunc, use:

              autoload +X myfunc

SPECIAL FUNCTIONS
       The following functions, if defined, have special meaning to the shell:

       chpwd  Executed whenever the current working directory is changed.

       periodic
              If the parameter PERIOD is set, this function is executed every
              $PERIOD seconds, just before a prompt.

       precmd Executed before each prompt.

       preexec
              Executed just after a command has been read and is about to be
              executed.  If the history mechanism is active (and the line was
              not discarded from the history buffer), the string that the user
              typed is passed as the first argument, otherwise it is an empty
              string.  The actual command that will be executed (including
              expanded aliases) is passed in two different forms: the second
              argument is a single-line, size-limited version of the command
              (with things like function bodies elided); the third argument
              contains the full text what what is being executed.

       TRAPNAL
              If defined and non-null, this function will be executed whenever
              the shell catches a signal SIGNAL, where NAL is a signal name as
              specified for the kill builtin.  The signal number will be
              passed as the first parameter to the function.

              If a function of this form is defined and null, the shell and
              processes spawned by it will ignore SIGNAL.

       TRAPDEBUG
              Executed after each command.

       TRAPEXIT
              Executed when the shell exits, or when the current function
              exits if defined inside a function.

       TRAPZERR
              Executed whenever a command has a non-zero exit status.
              However, the function is not executed if the command occurred in
              a sublist followed by `&&' or `||'; only the final command in a
              sublist of this type causes the trap to be executed.

       The functions beginning `TRAP' may alternatively be defined with the
       trap builtin:  this may be preferable for some uses, as they are then
       run in the environment of the calling process, rather than in their own
       function environment.  Apart from the difference in calling procedure
       and the fact that the function form appears in lists of functions, the
       forms

              TRAPNAL() {
               # code
              }

       and

              trap '
               # code

       are equivalent.

JOBS
       If the MONITOR option is set, an interactive shell associates a job
       with each pipeline.  It keeps a table of current jobs, printed by the
       jobs command, and assigns them small integer numbers.  When a job is
       started asynchronously with `&', the shell prints a line which looks
       like:

              [1] 1234

       indicating that the job which was started asynchronously was job number
       1 and had one (top-level) process, whose process ID was 1234.

       If a job is started with `&|' or `&!', then that job is immediately
       disowned.  After startup, it does not have a place in the job table,
       and is not subject to the job control features described here.

       If you are running a job and wish to do something else you may hit the
       key ^Z (control-Z) which sends a TSTP signal to the current job:  this
       key may be redefined by the susp option of the external stty command.
       The shell will then normally indicate that the job has been
       `suspended', and print another prompt.  You can then manipulate the
       state of this job, putting it in the background with the bg command, or
       run some other commands and then eventually bring the job back into the
       foreground with the foreground command fg.  A ^Z takes effect
       immediately and is like an interrupt in that pending output and unread
       input are discarded when it is typed.

       A job being run in the background will suspend if it tries to read from
       the terminal.  Background jobs are normally allowed to produce output,
       but this can be disabled by giving the command `stty tostop'.  If you
       set this tty option, then background jobs will suspend when they try to
       produce output like they do when they try to read input.

       When a command is suspended and continued later with the fg or wait
       builtins, zsh restores tty modes that were in effect when it was
       suspended.  This (intentionally) does not apply if the command is
       continued via `kill -CONT', nor when it is continued with bg.

       There are several ways to refer to jobs in the shell.  A job can be
       referred to by the process ID of any process of the job or by one of
       the following:

       %number
              The job with the given number.
       %string
              Any job whose command line begins with string.
       %?string
              Any job whose command line contains string.
       %%     Current job.
       %+     Equivalent to `%%'.
       %-     Previous job.

       The shell learns immediately whenever a process changes state.  It
       normally informs you whenever a job becomes blocked so that no further
       progress is possible.  If the NOTIFY option is not set, it waits until
       just before it prints a prompt before it informs you.

       When the monitor mode is on, each background job that completes
       triggers any trap set for CHLD.

       When you try to leave the shell while jobs are running or suspended,
       you will be warned that `You have suspended (running) jobs'.  You may
       use the jobs command to see what they are.  If you do this or
       immediately try to exit again, the shell will not warn you a second
       time; the suspended jobs will be terminated, and the running jobs will
       be sent a SIGHUP signal, if the HUP option is set.

       To avoid having the shell terminate the running jobs, either use the
       nohup command (see nohup(1)) or the disown builtin.

SIGNALS
       The INT and QUIT signals for an invoked command are ignored if the
       command is followed by `&' and the MONITOR option is not active.
       Otherwise, signals have the values inherited by the shell from its
       parent (but see the TRAPNAL special functions in the section
       `Functions').

ARITHMETIC EVALUATION
       The shell can perform integer and floating point arithmetic, either
       using the builtin let, or via a substitution of the form $((...)).  For
       integers, the shell is usually compiled to use 8-byte precision where
       this is available, otherwise precision is 4 bytes.  This can be tested,
       for example, by giving the command `print - $(( 12345678901 ))'; if the
       number appears unchanged, the precision is at least 8 bytes.  Floating
       point arithmetic is always double precision.

       The let builtin command takes arithmetic expressions as arguments; each
       is evaluated separately.  Since many of the arithmetic operators, as
       well as spaces, require quoting, an alternative form is provided: for
       any command which begins with a `((', all the characters until a
       matching `))' are treated as a quoted expression and arithmetic
       expansion performed as for an argument of let.  More precisely,
       `((...))' is equivalent to `let "..."'.  For example, the following
       statement

              (( val = 2 + 1 ))

       is equivalent to

              let "val = 2 + 1"

       both assigning the value 3 to the shell variable val and returning a
       zero status.

       Integers can be in bases other than 10.  A leading `0x' or `0X' denotes
       hexadecimal.  Integers may also be of the form `base#n', where base is
       a decimal number between two and thirty-six representing the arithmetic
       base and n is a number in that base (for example, `16#ff' is 255 in
       hexadecimal).  The base# may also be omitted, in which case base 10 is
       used.  For backwards compatibility the form `[base]n' is also accepted.

       It is also possible to specify a base to be used for output in the form
       `[#base]', for example `[#16]'.  This is used when outputting
       arithmetical substitutions or when assigning to scalar parameters, but
       an explicitly defined integer or floating point parameter will not be
       affected.  If an integer variable is implicitly defined by an
       arithmetic expression, any base specified in this way will be set as
       the variable's output arithmetic base as if the option `-i base' to the
       typeset builtin had been used.  The expression has no precedence and if
       it occurs more than once in a mathematical expression, the last
       encountered is used.  For clarity it is recommended that it appear at
       the beginning of an expression.  As an example:

              typeset -i 16 y
              print $(( [#8] x = 32, y = 32 ))
              print $x $y

       outputs first `8#40', the rightmost value in the given output base, and
       then `8#40 16#20', because y has been explicitly declared to have
       output base 16, while x (assuming it does not already exist) is
       implicitly typed by the arithmetic evaluation, where it acquires the
       output base 8.

       When an output base is specified using the `[#base]' syntax, an
       appropriate base prefix will be output if necessary, so that the value
       output is valid syntax for input.  If the # is doubled, for example
       `[##16]', then no base prefix is output.

       Floating point constants are recognized by the presence of a decimal
       point or an exponent.  The decimal point may be the first character of
       the constant, but the exponent character e or E may not, as it will be
       taken for a parameter name.

       An arithmetic expression uses nearly the same syntax, precedence, and
       associativity of expressions in C.  The following operators are
       supported (listed in decreasing order of precedence):

       + - ! ~ ++ --
              unary plus/minus, logical NOT, complement,
              {pre,post}{in,de}crement
       << >>  bitwise shift left, right
       &      bitwise AND
       ^      bitwise XOR
       |      bitwise OR
       **     exponentiation
       * / %  multiplication, division, modulus (remainder)
       + -    addition, subtraction
       < > <= >=
              comparison
       == !=  equality and inequality
       &&     logical AND
       || ^^  logical OR, XOR
       ? :    ternary operator
       = += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
              assignment
       ,      comma operator

       The operators `&&', `||', `&&=', and `||=' are short-circuiting, and
       only one of the latter two expressions in a ternary operator is
       evaluated.  Note the precedence of the bitwise AND, OR, and XOR
       operators.

       Mathematical functions can be called with the syntax `func(args)',
       where the function decides if the args is used as a string or a
       comma-separated list of arithmetic expressions. The shell currently
       defines no mathematical functions by default, but the module
       zsh/mathfunc may be loaded with the zmodload builtin to provide
       standard floating point mathematical functions.

       An expression of the form `##x' where x is any character sequence such
       as `a', `^A', or `\M-\C-x' gives the ASCII value of this character and
       an expression of the form `#foo' gives the ASCII value of the first
       character of the value of the parameter foo.  Note that this is
       different from the expression `$#foo', a standard parameter
       substitution which gives the length of the parameter foo.  `#\' is
       accepted instead of `##', but its use is deprecated.

       Named parameters and subscripted arrays can be referenced by name
       within an arithmetic expression without using the parameter expansion
       syntax.  For example,

              ((val2 = val1 * 2))

       assigns twice the value of $val1 to the parameter named val2.

       An internal integer representation of a named parameter can be
       specified with the integer builtin.  Arithmetic evaluation is performed
       on the value of each assignment to a named parameter declared integer
       in this manner.  Assigning a floating point number to an integer
       results in rounding down to the next integer.

       Likewise, floating point numbers can be declared with the float
       builtin; there are two types, differing only in their output format, as
       described for the typeset builtin.  The output format can be bypassed
       by using arithmetic substitution instead of the parameter substitution,
       i.e. `${float}' uses the defined format, but `$((float))' uses a
       generic floating point format.

       Promotion of integer to floating point values is performed where
       necessary.  In addition, if any operator which requires an integer
       (`~', `&', `|', `^', `%', `<<', `>>' and their equivalents with
       assignment) is given a floating point argument, it will be silently
       rounded down to the next integer.

       Scalar variables can hold integer or floating point values at different
       times; there is no memory of the numeric type in this case.

       If a variable is first assigned in a numeric context without previously
       being declared, it will be implicitly typed as integer or float and
       retain that type either until the type is explicitly changed or until
       the end of the scope.  This can have unforeseen consequences.  For
       example, in the loop

              for (( f = 0; f < 1; f += 0.1 )); do
              # use $f
              done

       if f has not already been declared, the first assignment will cause it
       to be created as an integer, and consequently the operation `f += 0.1'
       will always cause the result to be truncated to zero, so that the loop
       will fail.  A simple fix would be to turn the initialization into `f =
       0.0'.  It is therefore best to declare numeric variables with explicit
       types.

CONDITIONAL EXPRESSIONS
       A conditional expression is used with the [[ compound command to test
       attributes of files and to compare strings.  Each expression can be
       constructed from one or more of the following unary or binary
       expressions:

       -a file
              true if file exists.

       -b file
              true if file exists and is a block special file.

       -c file
              true if file exists and is a character special file.

       -d file
              true if file exists and is a directory.

       -e file
              true if file exists.

       -f file
              true if file exists and is a regular file.

       -g file
              true if file exists and has its setgid bit set.

       -h file
              true if file exists and is a symbolic link.

       -k file
              true if file exists and has its sticky bit set.

       -n string
              true if length of string is non-zero.

       -o option
              true if option named option is on.  option may be a single
              character, in which case it is a single letter option name.
              (See the section `Specifying Options'.)

       -p file
              true if file exists and is a FIFO special file (named pipe).

       -r file
              true if file exists and is readable by current process.

       -s file
              true if file exists and has size greater than zero.

       -t fd  true if file descriptor number fd is open and associated with a
              terminal device.  (note: fd is not optional)

       -u file
              true if file exists and has its setuid bit set.

       -w file
              true if file exists and is writable by current process.

       -x file
              true if file exists and is executable by current process.  If
              file exists and is a directory, then the current process has
              permission to search in the directory.

       -z string
              true if length of string is zero.

       -L file
              true if file exists and is a symbolic link.

       -O file
              true if file exists and is owned by the effective user ID of
              this process.

       -G file
              true if file exists and its group matches the effective group ID
              of this process.

       -S file
              true if file exists and is a socket.

       -N file
              true if file exists and its access time is not newer than its
              modification time.

       file1 -nt file2
              true if file1 exists and is newer than file2.

       file1 -ot file2
              true if file1 exists and is older than file2.

       file1 -ef file2
              true if file1 and file2 exist and refer to the same file.

       string = pattern
       string == pattern
              true if string matches pattern.  The `==' form is the preferred
              one.  The `=' form is for backward compatibility and should be
              considered obsolete.

       string != pattern
              true if string does not match pattern.

       string1 < string2
              true if string1 comes before string2 based on ASCII value of
              their characters.

       string1 > string2
              true if string1 comes after string2 based on ASCII value of
              their characters.

       exp1 -eq exp2
              true if exp1 is numerically equal to exp2.

       exp1 -ne exp2
              true if exp1 is numerically not equal to exp2.

       exp1 -lt exp2
              true if exp1 is numerically less than exp2.

       exp1 -gt exp2
              true if exp1 is numerically greater than exp2.

       exp1 -le exp2
              true if exp1 is numerically less than or equal to exp2.

       exp1 -ge exp2
              true if exp1 is numerically greater than or equal to exp2.

       ( exp )
              true if exp is true.

       ! exp  true if exp is false.

       exp1 && exp2
              true if exp1 and exp2 are both true.

       exp1 || exp2
              true if either exp1 or exp2 is true.

       Normal shell expansion is performed on the file, string and pattern
       arguments, but the result of each expansion is constrained to be a
       single word, similar to the effect of double quotes.  However, pattern
       metacharacters are active for the pattern arguments; the patterns are
       the same as those used for filename generation, see zshexpn(1), but
       there is no special behaviour of `/' nor initial dots, and no glob
       qualifiers are allowed.

       In each of the above expressions, if file is of the form `/dev/fd/n',
       where n is an integer, then the test applied to the open file whose
       descriptor number is n, even if the underlying system does not support
       the /dev/fd directory.

       In the forms which do numeric comparison, the expressions exp undergo
       arithmetic expansion as if they were enclosed in $((...)).

       For example, the following:

              [[ ( -f foo || -f bar ) && $report = y* ]] && print File exists.

       tests if either file foo or file bar exists, and if so, if the value of
       the parameter report begins with `y'; if the complete condition is
       true, the message `File exists.' is printed.

PROMPT EXPANSION
       Prompt sequences undergo a special form of expansion.  This type of
       expansion is also available using the -P option to the print builtin.

       If the PROMPT_SUBST option is set, the prompt string is first subjected
       to parameter expansion, command substitution and arithmetic expansion.
       See zshexpn(1).

       Certain escape sequences may be recognised in the prompt string.

       If the PROMPT_BANG option is set, a `!' in the prompt is replaced by
       the current history event number.  A literal `!' may then be
       represented as `!!'.

       If the PROMPT_PERCENT option is set, certain escape sequences that
       start with `%' are expanded.  Some escapes take an optional integer
       argument, which should appear between the `%' and the next character of
       the sequence.  The following escape sequences are recognized:

       %%     A `%'.

       %)     A `)'.

       %d
       %/     Present working directory ($PWD).  If an integer follows the
              `%', it specifies a number of trailing components of $PWD to
              show; zero means the whole path.  A negative integer specifies
              leading components, i.e. %-1d specifies the first component.

       %~     As %d and %/, but if $PWD has a named directory as its prefix,
              that part is replaced by a `~' followed by the name of the
              directory.  If it starts with $HOME, that part is replaced by a
              `~'.

       %h
       %!     Current history event number.

       %L     The current value of $SHLVL.

       %M     The full machine hostname.

       %m     The hostname up to the first `.'.  An integer may follow the `%'
              to specify how many components of the hostname are desired.
              With a negative integer, trailing components of the hostname are
              shown.

       %S (%s)
              Start (stop) standout mode.

       %U (%u)
              Start (stop) underline mode.

       %B (%b)
              Start (stop) boldface mode.

       %t
       %@     Current time of day, in 12-hour, am/pm format.

       %T     Current time of day, in 24-hour format.

       %*     Current time of day in 24-hour format, with seconds.

       %n     $USERNAME.

       %N     The name of the script, sourced file, or shell function that zsh
              is currently executing, whichever was started most recently.  If
              there is none, this is equivalent to the parameter $0.  An
              integer may follow the `%' to specify a number of trailing path
              components to show; zero means the full path.  A negative
              integer specifies leading components.

       %i     The line number currently being executed in the script, sourced
              file, or shell function given by %N.  This is most useful for
              debugging as part of $PS4.

       %w     The date in day-dd format.

       %W     The date in mm/dd/yy format.

       %D     The date in yy-mm-dd format.

       %D{string}
              string is formatted using the strftime function.  See
              strftime(3) for more details.  Three additional codes are
              available:  %f prints the day of the month, like %e but without
              any preceding space if the day is a single digit, and %K/%L
              correspond to %k/%l for the hour of the day (24/12 hour clock)
              in the same way.

       %l     The line (tty) the user is logged in on without /dev/ prefix.
              If name starts with /dev/tty this is stripped.

       %y     The line (tty) the user is logged in on without /dev/ prefix.
              It does not treat /dev/tty* specially.

       %?     The return code of the last command executed just before the
              prompt.

       %_     The status of the parser, i.e. the shell constructs (like `if'
              and `for') that have been started on the command line. If given
              an integer number that many strings will be printed; zero or
              negative or no integer means print as many as there are.  This
              is most useful in prompts PS2 for continuation lines and PS4 for
              debugging with the XTRACE option; in the latter case it will
              also work non-interactively.

       %E     Clears to end of line.

       %#     A `#' if the shell is running with privileges, a `%' if not.
              Equivalent to `%(!.#.%%)'.  The definition of `privileged', for
              these purposes, is that either the effective user ID is zero,
              or, if POSIX.1e capabilities are supported, that at least one
              capability is raised in either the Effective or Inheritable
              capability vectors.

       %v     The value of the first element of the psvar array parameter.
              Following the `%' with an integer gives that element of the
              array.  Negative integers count from the end of the array.

       %{...%}
              Include a string as a literal escape sequence.  The string
              within the braces should not change the cursor position.  Brace
              pairs can nest.

       %(x.true-text.false-text)
              Specifies a ternary expression.  The character following the x
              is arbitrary; the same character is used to separate the text
              for the `true' result from that for the `false' result.  This
              separator may not appear in the true-text, except as part of a
              %-escape sequence.  A `)' may appear in the false-text as `%)'.
              true-text and false-text may both contain arbitrarily-nested
              escape sequences, including further ternary expressions.

              The left parenthesis may be preceded or followed by a positive
              integer n, which defaults to zero.  A negative integer will be
              multiplied by -1.  The test character x may be any of the
              following:

              c
              .
              ~      True if the current path, with prefix replacement, has at
                     least n elements.
              /
              C      True if the current absolute path has at least n
                     elements.
              t      True if the time in minutes is equal to n.
              T      True if the time in hours is equal to n.
              d      True if the day of the month is equal to n.
              D      True if the month is equal to n (January = 0).
              w      True if the day of the week is equal to n (Sunday = 0).
              ?      True if the exit status of the last command was n.
              #      True if the effective uid of the current process is n.
              g      True if the effective gid of the current process is n.
              l      True if at least n characters have already been printed
                     on the current line.
              L      True if the SHLVL parameter is at least n.
              S      True if the SECONDS parameter is at least n.
              v      True if the array psvar has at least n elements.
              _      True if at least n shell constructs were started.
              !      True if the shell is running with privileges.

       %<string<
       %>string>
       %[xstring]
              Specifies truncation behaviour for the remainder of the prompt
              string.  The third, deprecated, form is equivalent to
              `%xstringx', i.e. x may be `<' or `>'.  The numeric argument,
              which in the third form may appear immediately after the `[',
              specifies the maximum permitted length of the various strings
              that can be displayed in the prompt.  The string will be
              displayed in place of the truncated portion of any string; note
              this does not undergo prompt expansion.

              The forms with `<' truncate at the left of the string, and the
              forms with `>' truncate at the right of the string.  For
              example, if the current directory is `/home/pike', the prompt
              `%8<..<%/' will expand to `..e/pike'.  In this string, the
              terminating character (`<', `>' or `]'), or in fact any
              character, may be quoted by a preceding `\'; note when using
              print -P, however, that this must be doubled as the string is
              also subject to standard print processing, in addition to any
              backslashes removed by a double quoted string:  the worst case
              is therefore `print -P "%<\\\\<<..."'.

              If the string is longer than the specified truncation length, it
              will appear in full, completely replacing the truncated string.

              The part of the prompt string to be truncated runs to the end of
              the string, or to the end of the next enclosing group of the
              `%(' construct, or to the next truncation encountered at the
              same grouping level (i.e. truncations inside a `%(' are
              separate), which ever comes first.  In particular, a truncation
              with argument zero (e.g. `%<<') marks the end of the range of
              the string to be truncated while turning off truncation from
              there on. For example, the prompt '%10<...<%~%<<%# ' will print
              a truncated representation of the current directory, followed by
              a `%' or `#', followed by a space.  Without the `%<<', those two
              characters would be included in the string to be truncated.

       %c
       %.
       %C     Trailing component of $PWD.  An integer may follow the `%' to
              get more than one component.  Unless `%C' is used, tilde
              contraction is performed first.  These are deprecated as %c and
              %C are equivalent to %1~ and %1/, respectively, while explicit
              positive integers have the same effect as for the latter two
              sequences.

zsh 4.0.6                       August 14, 2002                     ZSHMISC(1)

NAME | SIMPLE COMMANDS & PIPELINES | PRECOMMAND MODIFIERS | COMPLEX COMMANDS | ALTERNATE FORMS FOR COMPLEX COMMANDS | RESERVED WORDS | COMMENTS | ALIASING | QUOTING | REDIRECTION | MULTIOS | REDIRECTIONS WITH NO COMMAND | COMMAND EXECUTION | FUNCTIONS | AUTOLOADING FUNCTIONS | SPECIAL FUNCTIONS | JOBS | SIGNALS | ARITHMETIC EVALUATION | CONDITIONAL EXPRESSIONS | PROMPT EXPANSION

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