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zshmisc(1)





NAME

       zshmisc - everything and then some


SIMPLE COMMANDS & PIPELINES

       A  simple  command is a sequence of optional parameter assignments fol-
       lowed by  blank-separated  words,  with  optional  redirections  inter-
       spersed.  The first word is the command to be executed, and the remain-
       ing 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 pipe-
       line 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 ordi-
       nary 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 status).  If two pipelines are separated by `||', the
       second is executed only if the first fails (returns a nonzero  status).
       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 com-
       mand which will be executed if and only if the grep command  returns  a
       zero  status.   If it does not, the value of the sublist is that return
       status, else it is the status 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 what-
       soever,  including the complex commands below; this is implied wherever
       the word `list' appears in later descriptions.  For example,  the  com-
       mands 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 inter-
              preted 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 status is zero, the then list is executed.  If each
              elif list returns nonzero status, 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, exe-
              cuting list each time.  If the in word is omitted, use the posi-
              tional parameters instead of the words.

              More  than  one  parameter  name  can  appear before the list of
              words.  If N names are given, then on each execution of the loop
              the  next  N words are assigned to the corresponding parameters.
              If there are more names  than  remaining  words,  the  remaining
              parameters  are  each set to the empty string.  Execution of the
              loop ends when there is no remaining word to assign to the first
              name.  It is only possible for in to appear as the first name in
              the list, else it will be treated as  marking  the  end  of  the
              list.

       for (( [expr1] ; [expr2] ; [expr3] )) do list done
              The arithmetic expression expr1 is evaluated first (see the sec-
              tion `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.  The rule for the ter-
              minator of the following list ;;, ;& or ;| is applied unless the
              esac is reached.

              If  the  list  that  is executed is terminated with ;| the shell
              continues to scan the patterns looking for the next match,  exe-
              cuting  the  corresponding  list,  and applying the rule for the
              corresponding terminator ;;, ;& or ;|.  Note that  word  is  not
              re-expanded;  all  applicable  patterns are tested with the same
              word.

       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  selec-
              tion 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.

       { try-list } always { always-list }
              First execute try-list.  Regardless of errors,  or  break,  con-
              tinue,  or  return commands encountered within try-list, execute
              always-list.  Execution then continues from the  result  of  the
              execution of try-list; in other words, any error, or break, con-
              tinue, or return command is treated in the  normal  way,  as  if
              always-list  were  not  present.   The  two  chunks  of code are
              referred to as the `try block' and the `always block'.

              Optional newlines or semicolons may  appear  after  the  always;
              note,  however,  that they may not appear between the preceeding
              closing brace and the always.

              An `error' in this context is a condition such as a syntax error
              which  causes  the shell to abort execution of the current func-
              tion, script, or list.   Syntax  errors  encountered  while  the
              shell  is  parsing  the  code do not cause the always-list to be
              executed.  For example, an erroneously constructed if  block  in
              try-list  would cause the shell to abort during parsing, so that
              always-list would not be executed, while an erroneous  substitu-
              tion  such as ${*foo*} would cause a run-time error, after which
              always-list would be executed.

              An error condition can be tested  and  reset  with  the  special
              integer  variable  TRY_BLOCK_ERROR.   Outside an always-list the
              value is irrelevant,  but  it  is  initialised  to  -1.   Inside
              always-list,  the  value  is  1  if  an  error  occurred  in the
              try-list, else 0.  If TRY_BLOCK_ERROR is set  to  0  during  the
              always-list,  the  error  condition  caused  by  the try-list is
              reset, and shell execution continues normally after the  end  of
              always-list.  Altering the value during the try-list is not use-
              ful (unless this forms part of an enclosing always block).

              Regardless of TRY_BLOCK_ERROR, after the end of always-list  the
              normal  shell  status $? is the value returned from always-list.
              This  will  be  non-zero  if  there  was  an  error,   even   if
              TRY_BLOCK_ERROR was set to zero.

              The  following  executes  the given code, ignoring any errors it
              causes.  This is an alternative to the usual convention of  pro-
              tecting code by executing it in a subshell.

                     {
                         # code which may cause an error
                       } always {
                         # This code is executed regardless of the error.
                         (( TRY_BLOCK_ERROR = 0 ))
                     }
                     # The error condition has been reset.

              An  exit  command (or a return command executed at the outermost
              function level of a script) encountered  in  try-list  does  not
              cause  the  execution  of always-list.  Instead, the shell exits
              immediately after any EXIT trap has been executed.

       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 parame-
              ter.  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 com-
       mands, in both these cases the test part of the loop must also be suit-
       ably  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 INTERAC-
       TIVE_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  com-
       mand),  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 pre-
       ceding 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 con-
       sidered 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 pro-
       duces  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 CLOB-
              BER  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 substitu-
              tion 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.

              Note that word itself does not undergo shell  expansion.   Back-
              quotes  in  word  do  not  have their usual effect; instead they
              behave similarly to double quotes, except  that  the  backquotes
              themselves  are  passed through unchanged.  (This information is
              given for completeness and it is not recommended that backquotes
              be  used.)  Quotes in the form $'...' have their standard effect
              of expanding backslashed references to special characters.

              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.  Compare the use of word
              in  here-documents  above,  where  word  does  not undergo shell
              expansion.

       <& 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 sec-
              tion below).

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

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

       >>&| word
       >>&! word
       &>>| word
       &>>! word
              Redirects both standard output and standard error (file descrip-
              tor 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  descrip-
       tor 2 would be associated with the terminal (assuming file descriptor 1
       had been) and then file descriptor 1  would  be  associated  with  file
       fname.

       If instead of a digit one of the operators above is preceded by a valid
       identifier enclosed in braces, the shell will open a new file  descrip-
       tor that is guaranteed to be at least 10 and set the parameter named by
       the identifier to the file descriptor opened.  No whitespace is allowed
       between  the  closing  brace and the redirection character.  The option
       IGNORE_BRACES must not be set.  For example:

              ... {myfd}>&1

       This opens a new file descriptor that is a duplicate of file descriptor
       1  and  sets  the  parameter myfd to the number of the file descriptor,
       which will be at least 10.  The new file descriptor can be  written  to
       using the syntax >&$myfd.

       The  syntax  {varid}>&-,  for example {myfd}>&-, may be used to close a
       file descriptor opened in this fashion.  Note that the parameter  given
       by varid must previously be set to a file descriptor in this case.

       It  is an error to open or close a file descriptor in this fashion when
       the parameter is readonly.  However, it is not  an  error  to  read  or
       write  a  file  descriptor using <&$param or >&$param if param is read-
       only.

       If the option CLOBBER is unset, it is an error to open a file  descrip-
       tor  using  a  parameter that is already set to an open file descriptor
       previously allocated by this mechanism.  Unsetting the parameter before
       using it for allocating a file descriptor avoids the error.

       Note  that this mechanism merely allocates or closes a file descriptor;
       it does not perform any redirections from or to it.  It is usually con-
       venient  to  allocate  a file descriptor prior to use as an argument to
       exec.  The following shows a typical sequence of allocation,  use,  and
       closing of a file descriptor:

              integer myfd
              exec {myfd}>~/logs/mylogfile.txt
              print This is a log message. >&$myfd
              exec {myfd}>&-

       Note  that  the  expansion  of  the  variable in the expression >&$myfd
       occurs at the point the redirection  is  opened.   This  is  after  the
       expansion  of  command arguments and after any redirections to the left
       on the command line have been processed.

       The `|&' command separator described in Simple Commands & Pipelines  in
       zshmisc(1) is a shorthand for `2>&1 |'.

       The  various  forms of process substitution, `<(list)', and `=(list())'
       for input and `>(list)' for output, are often used together with  redi-
       rection.   For example, if word in an output redirection is of the form
       `>(list)' then the output is piped to the command represented by  list.
       See Process Substitution in zshexpn(1).


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'.

       Expansion of the redirection argument occurs at the point the redirect-
       ion is opened, at the point described above for the  expansion  of  the
       variable in >&$myfd.

       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.

       There  is  a  problem  when an output multio is attached to an external
       program.  A simple example shows this:

              cat file >file1 >file2
              cat file1 file2

       Here, it is possible that the second `cat' will not  display  the  full
       contents  of  file1  and  file2  (i.e.  the  original  contents of file
       repeated twice).

       The reason for this is that the  multios  are  spawned  after  the  cat
       process  is  forked from the parent shell, so the parent shell does not
       wait for the multios to finish writing data.  This means the command as
       shown  can  exit  before  file1 and file2 are completely written.  As a
       workaround, it is possible to run the cat process as part of a  job  in
       the current shell:

              { cat file } >file >file2

       Here, the {...} job will pause to wait for both files to be written.


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 com-
       mand 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  unsuc-
       cessful,  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 oper-
       ating  systems that do not handle this executable format in the kernel.


FUNCTIONS

       Shell functions are defined with the function reserved word or the spe-
       cial  syntax  `funcname  ()'.   Shell  functions are read in and stored
       internally.  Alias names are resolved when the function is read.  Func-
       tions  are  executed  like  commands with the arguments passed as posi-
       tional 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 envi-
       ronment of the caller.

       The return builtin is used to return from function calls.

       Function  identifiers  can be listed with the functions builtin.  Func-
       tions 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 rec-
       ommended 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 cor-
       responding 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 defini-
              tions as well, but those are neither loaded nor executed; a file
              found  in  this way is searched only for the definition of func-
              tion.

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

       In  summary, the order of searching is, first, in the parents of direc-
       tories in fpath for the newer of  either  a  compiled  directory  or  a
       directory  in fpath; second, if more than one of these contains a defi-
       nition 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 execu-
       tion, 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 initializa-
       tion and then call the function defined, the file should  contain  ini-
       tialization 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  ini-
       tialization  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  follow-
       ing 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.  This is done so that

              eval "$(functions)"

       produces a reasonable result.  A true autoloaded function can be  iden-
       tified  by  the  presence  of  the  comment  `# undefined' in the body,
       because all comments are discarded from defined functions.

       To load the definition of an autoloaded function myfunc without execut-
       ing myfunc, use:

              autoload +X myfunc


SPECIAL FUNCTIONS

       Certain functions, if defined, have special meaning to the shell.

       In  the  case  of chpwd, periodic, precmd and preexec it is possible to
       define an array that has the same name with `_functions' appended.  Any
       element in such an array is taken as the name of a function to execute;
       it is executed in the same context and with the same arguments  as  the
       basic  function.  For example, if $chpwd_functions is an array contain-
       ing  the  values  `mychpwd',  `chpwd_save_dirstack',  then  the   shell
       attempts    to   execute   the   functions   `chpwd',   `mychpwd'   and
       `chpwd_save_dirstack', in that order.  Any function that does not exist
       is silently ignored.  A function found by this mechanism is referred to
       elsewhere as a `hook function'.  An error in any function causes subse-
       quent  functions not to be run.  Note further that an error in a precmd
       hook causes an immediately  following  periodic  function  not  to  run
       (thought it may run at the next opportunity).

       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.  Note  that  if  multiple
              functions  are  defined  using the array periodic_functions only
              one period is applied to the complete set of functions, and  the
              scheduled time is not reset if the list of functions is altered.
              Hence the set of functions is always called together.

       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 that is being executed.

       zshexit
              Executed at the point where the main shell is about to exit nor-
              mally.   This  is  not called by exiting subshells, nor when the
              exec precommand modifier is used  before  an  external  command.
              Also, unlike TRAPEXIT, it is not called when functions exit.

       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.

              The return status from the function is handled specially.  If it
              is zero, the signal is assumed to have been handled, and  execu-
              tion  continues  normally.   Otherwise, the shell will behave as
              interrupted except  that  the  return  status  of  the  trap  is
              retained.

              Programs  terminated  by  uncaught  signals typically return the
              status 128 plus the signal number.  Hence the  following  causes
              the  handler for SIGINT to print a message, then mimic the usual
              effect of the signal.

                     TRAPINT() {
                       print "Caught SIGINT, aborting."
                       return $(( 128 + $1 ))
                     }

              The functions TRAPZERR, TRAPDEBUG and TRAPEXIT  are  never  exe-
              cuted inside other traps.

       TRAPDEBUG
              Executed after each command.

       TRAPEXIT
              Executed  when  the  shell  exits,  or when the current function
              exits if defined inside a function.  The  value  of  $?  at  the
              start of execution is the exit status of the shell or the return
              status of the function exiting.

       TRAPZERR
              Executed whenever a command has a non-zero  exit  status.   How-
              ever,  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 func-
              tion TRAPERR acts the same as TRAPZERR on systems where there is
              no SIGERR (this is the usual case).

       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
              ' NAL

       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 to standard
       error 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  `sus-
       pended',  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  immedi-
       ately  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 sus-
       pended.  This (intentionally) does not apply if the command is  contin-
       ued 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 nor-
       mally 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.  All such notifi-
       cations  are  sent directly to the terminal, not to the standard output
       or standard error.

       When the monitor mode is on, each background job that  completes  trig-
       gers 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 immedi-
       ately 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 com-
       mand is followed by `&' and the MONITOR  option  is  not  active.   The
       shell  itself  always ignores the QUIT signal.  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 match-
       ing  `))'  are  treated as a quoted expression and arithmetic expansion
       performed as for an argument of  let.   More  precisely,  `((...))'  is
       equivalent  to  `let  "..."'.  The return status is 0 if the arithmetic
       value of the expression is non-zero, and 1 otherwise.

       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  arith-
       metical  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 arith-
       metic 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 encoun-
       tered 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  out-
       put base 16, while x (assuming it does not already exist) is implicitly
       typed by the arithmetic evaluation, where it acquires the  output  base
       8.

       If  the  C_BASES  option  is set, hexadecimal numbers in the standard C
       format, for example 0xFF instead of the usual `16#FF'.  If  the  option
       OCTAL_ZEROES  is also set (it is not by default), octal numbers will be
       treated similarly and hence appear as `077' instead  of  `8#77'.   This
       option  has no effect on the output of bases other than hexadecimal and
       octal, and these formats are always understood on input.

       When an output base is specified using the `[#base]' syntax, an  appro-
       priate  base prefix will be output if necessary, so that the value out-
       put 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 sup-
       ported (listed in decreasing order of precedence):

       + - ! ~ ++ --
              unary plus/minus, logical NOT, complement, {pre,post}{in,de}cre-
              ment
       << >>  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  evalu-
       ated.  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/math-
       func may be loaded with the zmodload builtin to provide standard float-
       ing 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 value of this character and an
       expression of the form `#foo' gives the value of the first character of
       the  contents  of the parameter foo.  Character values are according to
       the character set used in the current locale; for  multibyte  character
       handling the option MULTIBYTE must be set.  Note that this form is dif-
       ferent from `$#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  speci-
       fied  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 neces-
       sary.  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 expres-
       sions:

       -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 char-
              acter,  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 sin-
       gle 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  repre-
       sented 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:

   Special characters
       %%     A `%'.

       %)     A `)'.

   Login information
       %l     The line (tty) the user is logged in on, without `/dev/' prefix.
              If the name starts with `/dev/tty', that prefix is stripped.

       %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.

       %n     $USERNAME.

       %y     The line (tty) the user is logged in on, without `/dev/' prefix.
              This does not treat `/dev/tty' names specially.

   Shell state
       %#     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.

       %?     The return status 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.

       %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.

       %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.

       %j     The number of jobs.

       %L     The current value of $SHLVL.

       %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 inte-
              ger may follow the `%' to specify a number of trailing path com-
              ponents  to  show; zero means the full path.  A negative integer
              specifies leading components.

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

   Date and time
       %D     The date in yy-mm-dd format.

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

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

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

       %w     The date in day-dd format.

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

       %D{string}
              string  is  formatted  using  the  strftime function.  See strf-
              time(3) for more details.  Three additional codes are available:
              %f  prints the day of the month, like %e but without any preced-
              ing 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.

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

       %E     Clear to end of line.

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

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

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

   Conditional substrings
       %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.

       %(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  fol-
              lowing:

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

       %<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 dis-
              played 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  exam-
              ple,  if  the  current  directory  is  `/home/pike',  the prompt
              `%8<..<%/' will expand to `..e/pike'.  In this string, the  ter-
              minating  character (`<', `>' or `]'), or in fact any character,
              may be quoted by a preceding `\'; note when using print -P, how-
              ever, 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 sepa-
              rate), 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.

zsh 4.3.4                       April 19, 2006                      ZSHMISC(1)

Man(1) output converted with man2html