zshmodules - zsh loadable modules

Some optional parts of zsh are in modules, separate from the core of the shell. Each of these modules may be linked in to the shell at build time, or can be dynamically linked while the shell is running if the installation supports this feature. The modules that are bundled with the zsh distribution are:

zsh/cap Builtins for manipulating POSIX.1e (POSIX.6) capability (privilege) sets.

zsh/clone

A builtin that can clone a running shell onto another terminal.

zsh/compctl

The compctl builtin for controlling completion.

zsh/complete

The basic completion code.

zsh/complist

Completion listing extensions.

zsh/computil

A module with utility builtins needed for the shell function based completion system.

zsh/datetime

Some date/time commands and parameters.

zsh/deltochar

A ZLE function duplicating EMACS' zap-to-char.

zsh/example

An example of how to write a module.

zsh/files

Some basic file manipulation commands as builtins.

zsh/mapfile

Access to external files via a special associative array.

zsh/mathfunc

Standard scientific functions for use in mathematical evaluations.

zsh/parameter

Access to internal hash tables via special associative arrays.

zsh/pcre

Interface to the PCRE library.

zsh/sched

A builtin that provides a timed execution facility within the shell.

zsh/net/socket

Manipulation of Unix domain sockets

zsh/stat

A builtin command interface to the stat system call.

zsh/system

A builtin interface to various low-level system features.

zsh/net/tcp

Manipulation of TCP sockets

zsh/termcap

Interface to the termcap database.

zsh/terminfo

Interface to the terminfo database.

zsh/zftp

A builtin FTP client.

zsh/zle

The Zsh Line Editor, including the bindkey and vared builtins.

zsh/zleparameter

Access to internals of the Zsh Line Editor via parameters.

zsh/zprof

A module allowing profiling for shell functions.

zsh/zpty

A builtin for starting a command in a pseudo-terminal.

zsh/zselect

Block and return when file descriptors are ready.

zsh/zutil

Some utility builtins, e.g. the one for supporting configuration via styles.

The zsh/cap module is used for manipulating POSIX.1e (POSIX.6) capability sets. If the operating system does not support this interface, the builtins defined by this module will do nothing. The builtins in this module are:

cap [ capabilities ] Change the shell's process capability sets to the specified capabilities, otherwise display the shell's current capabilities.

getcap filename ...

This is a built-in implementation of the POSIX standard utility. It displays the capability sets on each specified filename.

setcap capabilities filename ...

This is a built-in implementation of the POSIX standard utility. It sets the capability sets on each specified filename to the specified capabilities.

The zsh/clone module makes available one builtin command:

clone tty Creates a forked instance of the current shell, attached to the specified tty. In the new shell, the PID, PPID and TTY special parameters are changed appropriately. $! is set to zero in the new shell, and to the new shell's PID in the original shell.

The return value of the builtin is zero in both shells if successful, and non-zero on error.

The target of clone should be an unused terminal, such as an unused virtual console or a virtual terminal created by

xterm -e sh -c 'trap : INT QUIT TSTP; tty; while :; do sleep 100000000; done'

Some words of explanation are warranted about this long xterm command line: when doing clone on a pseudo-terminal, some other session ("session" meant as a unix session group, or SID) is already owning the terminal. Hence the cloned zsh cannot acquire the pseudo-terminal as a controlling tty. That means two things:

the job control signals will go to the sh-started-by-xterm process group (that's why we disable INT QUIT and TSTP with trap; otherwise the while loop could get suspended or killed)

the cloned shell will have job control disabled, and the job control keys (control-C, control-\ and control-Z) will not work.

This does not apply when cloning to an unused vc.

Cloning to an used (and unprepared) terminal will result in two processes reading simultaneously from the same terminal, with input bytes going randomly to either process.

clone is mostly useful as a shell built-in replacement for openvt.

The zsh/compctl module makes available two builtin commands. compctl, is the old, deprecated way to control completions for ZLE. See zshcompctl(1). The other builtin command, compcall can be used in user-defined completion widgets, see zshcompwid(1).

The zsh/complete module makes available several builtin commands which can be used in user-defined completion widgets, see zshcompwid(1).

The zsh/complist module offers three extensions to completion listings: the ability to highlight matches in such a list, the ability to scroll through long lists and a different style of menu completion.

Colored completion listings

Scrolling in completion listings

Menu selection

bindkey -M menuselect '^M' send-break

The zsh/computil module adds several builtin commands that are used by some of the completion functions in the completion system based on shell functions (see zshcompsys(1) ). Except for compquote these builtin commands are very specialised and thus not very interesting when writing your own completion functions. In summary, these builtin commands are:

comparguments This is used by the _arguments function to do the argument and command line parsing. Like compdescribe it has an option -i to do the parsing and initialize some internal state and various options to access the state information to decide what should be completed.

compdescribe

This is used by the _describe function to build the displays for the matches and to get the strings to add as matches with their options. On the first call one of the options -i or -I should be supplied as the first argument. In the first case, display strings without the descriptions will be generated, in the second case, the string used to separate the matches from their descriptions must be given as the second argument and the descriptions (if any) will be shown. All other arguments are like the definition arguments to _describe itself.

Once compdescribe has been called with either the -i or the -I option, it can be repeatedly called with the -g option and the names of five arrays as its arguments. This will step through the different sets of matches and store the options in the first array, the strings with descriptions in the second, the matches for these in the third, the strings without descriptions in the fourth, and the matches for them in the fifth array. These are then directly given to compadd to register the matches with the completion code.

compfiles

Used by the _path_files function to optimize complex recursive filename generation (globbing). It does three things. With the -p and -P options it builds the glob patterns to use, including the paths already handled and trying to optimize the patterns with respect to the prefix and suffix from the line and the match specification currently used. The -i option does the directory tests for the ignore-parents style and the -r option tests if a component for some of the matches are equal to the string on the line and removes all other matches if that is true.

compgroups

Used by the _tags function to implement the internals of the group-order style. This only takes its arguments as names of completion groups and creates the groups for it (all six types: sorted and unsorted, both without removing duplicates, with removing all duplicates and with removing consecutive duplicates).

compquote [ -p ] names ...

There may be reasons to write completion functions that have to add the matches using the -Q option to compadd and perform quoting themselves. Instead of interpreting the first character of the all_quotes key of the compstate special association and using the q flag for parameter expansions, one can use this builtin command. The arguments are the names of scalar or array parameters and the values of these parameters are quoted as needed for the innermost quoting level. If the -p option is given, quoting is done as if there is some prefix before the values of the parameters, so that a leading equal sign will not be quoted.

The return value is non-zero in case of an error and zero otherwise.

comptags

comptry These implement the internals of the tags mechanism.

compvalues

Like comparguments, but for the _values function.

The zsh/datetime module makes available one builtin command:

strftime [ -s scalar ] format epochtime Output the date denoted by epochtime in the format specified.

If -s scalar is given, assign the date to scalar instead of printing it.

The zsh/datetime module makes available one parameter:

EPOCHSECONDS An integer value representing the number of seconds since the epoch.

The zsh/deltochar module makes available two ZLE functions:

delete-to-char Read a character from the keyboard, and delete from the cursor position up to and including the next (or, with repeat count n, the nth) instance of that character. Negative repeat counts mean delete backwards.

zap-to-char

This behaves like delete-to-char, except that the final occurrence of the character itself is not deleted.

The zsh/example module makes available one builtin command:

example [ -flags ] [ args ... ] Displays the flags and arguments it is invoked with.

The purpose of the module is to serve as an example of how to write a module.

The zsh/files module makes some standard commands available as builtins:

chgrp [ -Rs ] group filename ... Changes group of files specified. This is equivalent to chown with a user-spec argument of `:group'.

chown [ -Rs ] user-spec filename ...

Changes ownership and group of files specified.

The user-spec can be in four forms:

user

change owner to user; do not change group

user::

change owner to user; do not change group

user:

change owner to user; change group to user's primary group

user:group

change owner to user; change group to group

:group

do not change owner; change group to group

In each case, the `:' may instead be a `.'. The rule is that if there is a `:' then the separator is `:', otherwise if there is a `.' then the separator is `.', otherwise there is no separator.

Each of user and group may be either a username (or group name, as appropriate) or a decimal user ID (group ID). Interpretation as a name takes precedence, if there is an all-numeric username (or group name).

The -R option causes chown to recursively descend into directories, changing the ownership of all files in the directory after changing the ownership of the directory itself.

The -s option is a zsh extension to chown functionality. It enables paranoid behaviour, intended to avoid security problems involving a chown being tricked into affecting files other than the ones intended. It will refuse to follow symbolic links, so that (for example) ``chown luser /tmp/foo/passwd'' can't accidentally chown /etc/passwd if /tmp/foo happens to be a link to /etc. It will also check where it is after leaving directories, so that a recursive chown of a deep directory tree can't end up recursively chowning /usr as a result of directories being moved up the tree.

ln [ -dfis ] filename dest

ln [ -dfis ] filename ... dir Creates hard (or, with -s, symbolic) links. In the first form, the specified destination is created, as a link to the specified filename. In the second form, each of the filenames is taken in turn, and linked to a pathname in the specified directory that has the same last pathname component.

Normally, ln will not attempt to create hard links to directories. This check can be overridden using the -d option. Typically only the super-user can actually succeed in creating hard links to directories. This does not apply to symbolic links in any case.

By default, existing files cannot be replaced by links. The -i option causes the user to be queried about replacing existing files. The -f option causes existing files to be silently deleted, without querying. -f takes precedence.

mkdir [ -p ] [ -m mode ] dir ...

Creates directories. With the -p option, non-existing parent directories are first created if necessary, and there will be no complaint if the directory already exists. The -m option can be used to specify (in octal) a set of file permissions for the created directories, otherwise mode 777 modified by the current umask (see umask(2)) is used.

mv [ -fi ] filename dest

mv [ -fi ] filename ... dir Moves files. In the first form, the specified filename is moved to the specified destination. In the second form, each of the filenames is taken in turn, and moved to a pathname in the specified directory that has the same last pathname component.

By default, the user will be queried before replacing any file that the user cannot write to, but writable files will be silently removed. The -i option causes the user to be queried about replacing any existing files. The -f option causes any existing files to be silently deleted, without querying. -f takes precedence.

Note that this mv will not move files across devices. Historical versions of mv, when actual renaming is impossible, fall back on copying and removing files; if this behaviour is desired, use cp and rm manually. This may change in a future version.

rm [ -dfirs ] filename ...

Removes files and directories specified.

Normally, rm will not remove directories (except with the -r option). The -d option causes rm to try removing directories with unlink (see unlink(2)), the same method used for files. Typically only the super-user can actually succeed in unlinking directories in this way. -d takes precedence over -r.

By default, the user will be queried before removing any file that the user cannot write to, but writable files will be silently removed. The -i option causes the user to be queried about removing any files. The -f option causes files to be silently deleted, without querying, and suppresses all error indications. -f takes precedence.

The -r option causes rm to recursively descend into directories, deleting all files in the directory before removing the directory with the rmdir system call (see rmdir(2)).

The -s option is a zsh extension to rm functionality. It enables paranoid behaviour, intended to avoid common security problems involving a root-run rm being tricked into removing files other than the ones intended. It will refuse to follow symbolic links, so that (for example) ``rm /tmp/foo/passwd'' can't accidentally remove /etc/passwd if /tmp/foo happens to be a link to /etc. It will also check where it is after leaving directories, so that a recursive removal of a deep directory tree can't end up recursively removing /usr as a result of directories being moved up the tree.

rmdir dir ...

Removes empty directories specified.

sync

Calls the system call of the same name (see sync(2)), which flushes dirty buffers to disk. It might return before the I/O has actually been completed.

The zsh/mapfile module provides one special associative array parameter of the same name.

mapfile This associative array takes as keys the names of files; the resulting value is the content of the file. The value is treated identically to any other text coming from a parameter. The value may also be assigned to, in which case the file in question is written (whether or not it originally existed); or an element may be unset, which will delete the file in question. For example, `vared mapfile[myfile]' works as expected, editing the file `myfile'.

When the array is accessed as a whole, the keys are the names of files in the current directory, and the values are empty (to save a huge overhead in memory). Thus ${(k)mapfile} has the same affect as the glob operator *(D), since files beginning with a dot are not special. Care must be taken with expressions such as rm ${(k)mapfile}, which will delete every file in the current directory without the usual `rm *' test.

The parameter mapfile may be made read-only; in that case, files referenced may not be written or deleted.

Limitations

The zsh/mathfunc module provides standard mathematical functions for use when evaluating mathematical formulae. The syntax agrees with normal C and FORTRAN conventions, for example,

(( f = sin(0.3) ))

assigns the sine of 0.3 to the parameter f.

Most functions take floating point arguments and return a floating point value. However, any necessary conversions from or to integer type will be performed automatically by the shell. Apart from atan with a second argument and the abs, int and float functions, all functions behave as noted in the manual page for the corresponding C function, except that any arguments out of range for the function in question will be detected by the shell and an error reported.

The following functions take a single floating point argument: acos, acosh, asin, asinh, atan, atanh, cbrt, ceil, cos, cosh, erf, erfc, exp, expm1, fabs, floor, gamma, j0, j1, lgamma, log, log10, log1p, logb, sin, sinh, sqrt, tan, tanh, y0, y1. The atan function can optionally take a second argument, in which case it behaves like the C function atan2. The ilogb function takes a single floating point argument, but returns an integer.

The function signgam takes no arguments, and returns an integer, which is the C variable of the same name, as described in gamma(3). Note that it is therefore only useful immediately after a call to gamma or lgamma. Note also that `signgam()' and `signgam' are distinct expressions.

The following functions take two floating point arguments: copysign, fmod, hypot, nextafter.

The following take an integer first argument and a floating point second argument: jn, yn.

The following take a floating point first argument and an integer second argument: ldexp, scalb.

The function abs does not convert the type of its single argument; it returns the absolute value of either a floating point number or an integer. The functions float and int convert their arguments into a floating point or integer value (by truncation) respectively.

Note that the C pow function is available in ordinary math evaluation as the `**' operator and is not provided here.

The function rand48 is available if your system's mathematical library has the function erand48(3). It returns a pseudo-random floating point number between 0 and 1. It takes a single string optional argument.

If the argument is not present, the random number seed is initialised by three calls to the rand(3) function --- this produces the same random numbers as the next three values of $RANDOM.

If the argument is present, it gives the name of a scalar parameter where the current random number seed will be stored. On the first call, the value must contain at least twelve hexadecimal digits (the remainder of the string is ignored), or the seed will be initialised in the same manner as for a call to rand48 with no argument. Subsequent calls to rand48(param) will then maintain the seed in the parameter param as a string of twelve hexadecimal digits, with no base signifier. The random number sequences for different parameters are completely independent, and are also independent from that used by calls to rand48 with no argument.

For example, consider

print $(( rand48(seed) ))
print $(( rand48() ))
print $(( rand48(seed) ))

Assuming $seed does not exist, it will be initialised by the first call. In the second call, the default seed is initialised; note, however, that because of the properties of rand() there is a correlation between the seeds used for the two initialisations, so for more secure uses, you should generate your own 12-byte seed. The third call returns to the same sequence of random numbers used in the first call, unaffected by the intervening rand48().

The zsh/parameter module gives access to some of the internal hash tables used by the shell by defining some special parameters.

options The keys for this associative array are the names of the options that can be set and unset using the setopt and unsetopt builtins. The value of each key is either the string on if the option is currently set, or the string off if the option is unset. Setting a key to one of these strings is like setting or unsetting the option, respectively. Unsetting a key in this array is like setting it to the value off.

commands

This array gives access to the command hash table. The keys are the names of external commands, the values are the pathnames of the files that would be executed when the command would be invoked. Setting a key in this array defines a new entry in this table in the same way as with the hash builtin. Unsetting a key as in `unset "commands[foo]"' removes the entry for the given key from the command hash table.

functions

This associative array maps names of enabled functions to their definitions. Setting a key in it is like defining a function with the name given by the key and the body given by the value. Unsetting a key removes the definition for the function named by the key.

dis_functions

Like functions but for disabled functions.

builtins

This associative array gives information about the builtin commands currently enabled. The keys are the names of the builtin commands and the values are either `undefined' for builtin commands that will automatically be loaded from a module if invoked or `defined' for builtin commands that are already loaded.

dis_builtins

Like builtins but for disabled builtin commands.

reswords

This array contains the enabled reserved words.

dis_reswords

Like reswords but for disabled reserved words.

aliases

This maps the names of the regular aliases currently enabled to their expansions.

dis_aliases

Like aliases but for disabled regular aliases.

galiases

Like aliases, but for global aliases.

dis_galiases

Like galiases but for disabled global aliases.

saliases

Like raliases, but for suffix aliases.

dis_saliases

Like saliases but for disabled suffix aliases.

parameters

The keys in this associative array are the names of the parameters currently defined. The values are strings describing the type of the parameter, in the same format used by the t parameter flag, see zshexpn(1) . Setting or unsetting keys in this array is not possible.

modules

An associative array giving information about modules. The keys are the names of the modules loaded, registered to be autoloaded, or aliased. The value says which state the named module is in and is one of the strings `loaded', `autoloaded', or `alias:name', where name is the name the module is aliased to.

Setting or unsetting keys in this array is not possible.

dirstack

A normal array holding the elements of the directory stack. Note that the output of the dirs builtin command includes one more directory, the current working directory.

history

This associative array maps history event numbers to the full history lines.

historywords

A special array containing the words stored in the history.

jobdirs

This associative array maps job numbers to the directories from which the job was started (which may not be the current directory of the job).

jobtexts

This associative array maps job numbers to the texts of the command lines that were used to start the jobs.

jobstates

This associative array gives information about the states of the jobs currently known. The keys are the job numbers and the values are strings of the form `job-state:mark:pid=state...'. The job-state gives the state the whole job is currently in, one of `running', `suspended', or `done'. The mark is `+' for the current job, `-' for the previous job and empty otherwise. This is followed by one `pid=state' for every process in the job. The pids are, of course, the process IDs and the state describes the state of that process.

nameddirs

This associative array maps the names of named directories to the pathnames they stand for.

userdirs

This associative array maps user names to the pathnames of their home directories.

funcstack

This array contains the names of the functions currently being executed. The first element is the name of the function using the parameter.

The zsh/pcre module makes some commands available as builtins:

pcre_compile [ -aimx ] PCRE Compiles a perl-compatible regular expression.

Option -a will force the pattern to be anchored. Option -i will compile a case-insensitive pattern. Option -m will compile a multi-line pattern; that is, ^ and $ will match newlines within the pattern. Option -x will compile an extended pattern, wherein whitespace and # comments are ignored.

pcre_study

Studies the previously-compiled PCRE which may result in faster matching.

pcre_match [ -a arr ] string

Returns successfully if string matches the previously-compiled PCRE.

If the expression captures substrings within parentheses, pcre_match will set the array $match to those substrings, unless the -a option is given, in which case it will set the array arr.

The zsh/pcre module makes available the following test condition:

expr -pcre-match pcre Matches a string against a perl-compatible regular expression.

For example,

[[ "$text" -pcre-match ^d+$ ]] && print text variable contains only "d's".

The zsh/sched module makes available one builtin command:

sched [+]hh:mm command ...

sched [ -item ] Make an entry in the scheduled list of commands to execute. The time may be specified in either absolute or relative time. With no arguments, prints the list of scheduled commands. With the argument `-item', removes the given item from the list.

The zsh/net/socket module makes available one builtin command:

zsocket [ -altv ] [ -d fd ] [ args ] zsocket is implemented as a builtin to allow full use of shell command line editing, file I/O, and job control mechanisms.

Outbound Connections

Inbound Connections

The zsh/stat module makes available one builtin command:

stat [ -gnNolLtTrs ] [ -f fd ] [ -H hash ] [ -A array ] [ -F fmt ] [ +element ] [ file ... ] The command acts as a front end to the stat system call (see stat(2)). If the stat call fails, the appropriate system error message printed and status 1 is returned. The fields of struct stat give information about the files provided as arguments to the command. In addition to those available from the stat call, an extra element `link' is provided. These elements are:

device The number of the device on which the file resides.

inode

The unique number of the file on this device (`inode' number).

mode

The mode of the file; that is, the file's type and access permissions. With the -s option, this will be returned as a string corresponding to the first column in the display of the ls -l command.

nlink

The number of hard links to the file.

uid

The user ID of the owner of the file. With the -s option, this is displayed as a user name.

gid

The group ID of the file. With the -s option, this is displayed as a group name.

rdev

The raw device number. This is only useful for special devices.

size

The size of the file in bytes.

atime

mtime

ctime The last access, modification and inode change times of the file, respectively, as the number of seconds since midnight GMT on 1st January, 1970. With the -s option, these are printed as strings for the local time zone; the format can be altered with the -F option, and with the -g option the times are in GMT.

blksize

The number of bytes in one allocation block on the device on which the file resides.

block

The number of disk blocks used by the file.

link

If the file is a link and the -L option is in effect, this contains the name of the file linked to, otherwise it is empty. Note that if this element is selected (``stat +link'') then the -L option is automatically used.

A particular element may be selected by including its name preceded by a `+' in the option list; only one element is allowed. The element may be shortened to any unique set of leading characters. Otherwise, all elements will be shown for all files.

Options:

-A array Instead of displaying the results on standard output, assign them to an array, one struct stat element per array element for each file in order. In this case neither the name of the element nor the name of the files appears in array unless the -t or -n options were given, respectively. If -t is given, the element name appears as a prefix to the appropriate array element; if -n is given, the file name appears as a separate array element preceding all the others. Other formatting options are respected.

-H hash

Similar to -A, but instead assign the values to hash. The keys are the elements listed above. If the -n option is provided then the name of the file is included in the hash with key name.

-f fd

Use the file on file descriptor fd instead of named files; no list of file names is allowed in this case.

-F fmt

Supplies a strftime (see strftime(3)) string for the formatting of the time elements. The -s option is implied.

-g

Show the time elements in the GMT time zone. The -s option is implied.

-l

List the names of the type elements (to standard output or an array as appropriate) and return immediately; options other than -A and arguments are ignored.

-L

Perform an lstat (see lstat(2)) rather than a stat system call. In this case, if the file is a link, information about the link itself rather than the target file is returned. This option is required to make the link element useful.

-n

Always show the names of files. Usually these are only shown when output is to standard output and there is more than one file in the list.

-N

Never show the names of files.

-o

If a raw file mode is printed, show it in octal, which is more useful for human consumption than the default of decimal. A leading zero will be printed in this case. Note that this does not affect whether a raw or formatted file mode is shown, which is controlled by the -r and -s options, nor whether a mode is shown at all.

-r

Print raw data (the default format) alongside string data (the -s format); the string data appears in parentheses after the raw data.

-s

Print mode, uid, gid and the three time elements as strings instead of numbers. In each case the format is like that of ls -l.

-t

Always show the type names for the elements of struct stat. Usually these are only shown when output is to standard output and no individual element has been selected.

-T

Never show the type names of the struct stat elements.

The zsh/system module makes available three builtin commands and a parameter.

syserror [ -e errvar ] [ -p prefix ] [ errno | errname ] This command prints out the error message associated with errno, a system error number, followed by a newline to standard error.

Instead of the error number, a name errname, for example ENOENT, may be used. The set of names is the same as the contents of the array errnos, see below.

If the string prefix is given, it is printed in front of the error message, with no intervening space.

If errvar is supplied, the entire message, without a newline, is assigned to the parameter names errvar and nothing is output.

A return value of 0 indicates the message was successfully printed (although it may not be useful if the error number was out of the system's range), a return value of 1 indicates an error in the parameters, and a return value of 2 indicates the error name was not recognised (no message is printed for this).

sysread [ -c countvar ] [ -i infd ] [ -o outfd ]

[ -s bufsize ] [ -t timeout ] [ param ] Perform a single system read from file descriptor infd, or zero if that is not given. The result of the read is stored in param or REPLY if that is not given. If countvar is given, the number of bytes read is assigned to the parameter named by countvar.

The maximum number of bytes read is bufsize or 8192 if that is not given, however the command returns as soon as any number of bytes was successfully read.

If timeout is given, it specifies a timeout in seconds, which may be zero to poll the file descriptor. This is handled by the poll system call if available, otherwise the select system call if available.

If outfd is given, an attempt is made to write all the bytes just read to the file descriptor outfd. If this fails, because of a system error other than EINTR or because of an internal zsh error during an interrupt, the bytes read but not written are stored in the parameter named by param if supplied (no default is used in this case), and the number of bytes read but not written is stored in the parameter named by countvar if that is supplied. If it was successful, countvar contains the full number of bytes transferred, as usual, and param is not set.

The error EINTR (interrupted system call) is handled internally so that shell interrupts are transparent to the caller. Any other error causes a return.

The possible return values are

0 At least one byte of data was successfully read and, if appropriate, written.

1

There was an error in the parameters to the command. This is the only error for which a message is printed to standard error.

2

There was an error on the read, or on polling the input file descriptor for a timeout. The parameter ERRNO gives the error.

3

Data were successfully read, but there was an error writing them to outfd. The parameter ERRNO gives the error.

4

The attempt to read timed out. Note this does not set ERRNO as this is not a system error.

5

No system error occurred, but zero bytes were read. This usually indicates end of file. The parameters are set according to the usual rules; no write to outfd is attempted.

syswrite [ -c countvar ] [ -o outfd ] data

The data (a single string of bytes) are written to the file descriptor outfd, or 1 if that is not given, using the write system call. Multiple write operations may be used if the first does not write all the data.

If countvar is given, the number of byte written is stored in the parameter named by countvar; this may not be the full length of data if an error occurred.

The error EINTR (interrupted system call) is handled internally by retrying; otherwise an error causes the command to return. For example, if the file descriptor is set to non-blocking output, an error EAGAIN (on some systems, EWOULDBLOCK) may result in the command returning early.

The return status may be 0 for success, 1 for an error in the parameters to the command, or 2 for an error on the write; no error message is printed in the last case, but the parameter ERRNO will reflect the error that occurred.

errnos A readonly array of the names of errors defined on the system. These are typically macros defined in C by including the system header file errno.h. The index of each name (assuming the option KSH_ARRAYS is unset) corresponds to the error number. Error numbers num before the last known error which have no name are given the name Enum in the array.

Note that aliases for errors are not handled; only the canonical name is used.

The zsh/net/tcp module makes available one builtin command:

ztcp [ -acflLtv ] [ -d fd ] [ args ] ztcp is implemented as a builtin to allow full use of shell command line editing, file I/O, and job control mechanisms.

If ztcp is run with no options, it will output the contents of its session table.

If it is run with only the option -L, it will output the contents of the session table in a format suitable for automatic parsing. The option is ignored if given with a command to open or close a session. The output consists of a set of lines, one per session, each containing the following elements separated by spaces:

File descriptor The file descriptor in use for the connection. For normal inbound (I) and outbound (O) connections this may be read and written by the usual shell mechanisms. However, it should only be close with `ztcp -c'.

Connection type

A letter indicating how the session was created:

Z A session created with the zftp command.

L

A connection opened for listening with `ztcp -l'.

I

An inbound connection accepted with `ztcp -a'.

O

An outbound connection created with `ztcp host ...'.

The local host

This is usually set to an all-zero IP address as the address of the localhost is irrelevant.

The local port

This is likely to be zero unless the connection is for listening.

The remote host

This is the fully qualified domain name of the peer, if available, else an IP address. It is an all-zero IP address for a session opened for listening.

The remote port

This is zero for a connection opened for listening.

Outbound Connections

Inbound Connections

Closing Connections

Example

zmodload zsh/net/tcp
ztcp -l 5123
listenfd=$REPLY
ztcp -a $listenfd
fd=$REPLY

zmodload zsh/net/tcp
ztcp host1 5123
fd=$REPLY

print This is a message >&$fd

read -r line <&$fd; print -r - $line

ztcp -c $listenfd
ztcp -c $fd

ztcp -c $fd

The zsh/termcap module makes available one builtin command:

echotc cap [ arg ... ] Output the termcap value corresponding to the capability cap, with optional arguments.

The zsh/termcap module makes available one parameter:

termcap An associative array that maps termcap capability codes to their values.

The zsh/terminfo module makes available one builtin command:

echoti cap [ arg ] Output the terminfo value corresponding to the capability cap, instantiated with arg if applicable.

The zsh/terminfo module makes available one parameter:

terminfo An associative array that maps terminfo capability names to their values.

The zsh/zftp module makes available one builtin command:

zftp subcommand [ args ] The zsh/zftp module is a client for FTP (file transfer protocol). It is implemented as a builtin to allow full use of shell command line editing, file I/O, and job control mechanisms. Often, users will access it via shell functions providing a more powerful interface; a set is provided with the zsh distribution and is described in zshzftpsys(1). However, the zftp command is entirely usable in its own right.

All commands consist of the command name zftp followed by the name of a subcommand. These are listed below. The return status of each subcommand is supposed to reflect the success or failure of the remote operation. See a description of the variable ZFTP_VERBOSE for more information on how responses from the server may be printed.

Subcommands

zftp params ftp.elsewhere.xx juser '?Password for juser: '

Parameters

Functions

Problems

The zsh/zle module contains the Zsh Line Editor. See zshzle(1).

The zsh/zleparameter module defines two special parameters that can be used to access internal information of the Zsh Line Editor (see zshzle(1)).

keymaps This array contains the names of the keymaps currently defined.

widgets

This associative array contains one entry per widget defined. The name of the widget is the key and the value gives information about the widget. It is either the string `builtin' for builtin widgets, a string of the form `user:name' for user-defined widgets, where name is the name of the shell function implementing the widget, or it is a string of the form `completion:type:name', for completion widgets. In the last case type is the name of the builtin widgets the completion widget imitates in its behavior and name is the name of the shell function implementing the completion widget.

When loaded, the zsh/zprof causes shell functions to be profiled. The profiling results can be obtained with the zprof builtin command made available by this module. There is no way to turn profiling off other than unloading the module.

zprof [ -c ] Without the -c option, zprof lists profiling results to standard output. The format is comparable to that of commands like gprof.

At the top there is a summary listing all functions that were called at least once. This summary is sorted in decreasing order of the amount of time spent in each. The lines contain the number of the function in order, which is used in other parts of the list in suffixes of the form `[num]'.RE, then the number of calls made to the function. The next three columns list the time in milliseconds spent in the function and its descendents, the average time in milliseconds spent in the function and its descendents per call and the percentage of time spent in all shell functions used in this function and its descendents. The following three columns give the same information, but counting only the time spent in the function itself. The final column shows the name of the function.

After the summary, detailed information about every function that was invoked is listed, sorted in decreasing order of the amount of time spent in each function and its descendents. Each of these entries consists of descriptions for the functions that called the function described, the function itself, and the functions that were called from it. The description for the function itself has the same format as in the summary (and shows the same information). The other lines don't show the number of the function at the beginning and have their function named indented to make it easier to distinguish the line showing the function described in the section from the surrounding lines.

The information shown in this case is almost the same as in the summary, but only refers to the call hierarchy being displayed. For example, for a calling function the column showing the total running time lists the time spent in the described function and its descendents only for the times when it was called from that particular calling function. Likewise, for a called function, this columns lists the total time spent in the called function and its descendents only for the times when it was called from the function described.

Also in this case, the column showing the number of calls to a function also shows a slash and then the total number of invocations made to the called function.

As long as the zsh/zprof module is loaded, profiling will be done and multiple invocations of the zprof builtin command will show the times and numbers of calls since the module was loaded. With the -c option, the zprof builtin command will reset its internal counters and will not show the listing. )

The zsh/zpty module offers one builtin:

zpty [ -e ] [ -b ] name [ arg ... ] The arguments following name are concatenated with spaces between, then executed as a command, as if passed to the eval builtin. The command runs under a newly assigned pseudo-terminal; this is useful for running commands non-interactively which expect an interactive environment. The name is not part of the command, but is used to refer to this command in later calls to zpty.

With the -e option, the pseudo-terminal is set up so that input characters are echoed.

With the -b option, input to and output from the pseudo-terminal are made non-blocking.

zpty -d [ names ... ]

The second form, with the -d option, is used to delete commands previously started, by supplying a list of their names. If no names are given, all commands are deleted. Deleting a command causes the HUP signal to be sent to the corresponding process.

zpty -w [ -n ] name [ strings ... ]

The -w option can be used to send the to command name the given strings as input (separated by spaces). If the -n option is not given, a newline is added at the end.

If no strings are provided, the standard input is copied to the pseudo-terminal; this may stop before copying the full input if the pseudo-terminal is non-blocking.

Note that the command under the pseudo-terminal sees this input as if it were typed, so beware when sending special tty driver characters such as word-erase, line-kill, and end-of-file.

zpty -r [ -t ] name [ param [ pattern ] ]

The -r option can be used to read the output of the command name. With only a name argument, the output read is copied to the standard output. Unless the pseudo-terminal is non-blocking, copying continues until the command under the pseudo-terminal exits; when non-blocking, only as much output as is immediately available is copied. The return value is zero if any output is copied.

When also given a param argument, at most one line is read and stored in the parameter named param. Less than a full line may be read if the pseudo-terminal is non-blocking. The return value is zero if at least one character is stored in param.

If a pattern is given as well, output is read until the whole string read matches the pattern, even in the non-blocking case. The return value is zero if the string read matches the pattern, or if the command has exited but at least one character could still be read. As of this writing, a maximum of one megabyte of output can be consumed this way; if a full megabyte is read without matching the pattern, the return value is non-zero.

In all cases, the return value is non-zero if nothing could be read, and is 2 if this is because the command has finished.

If the -r option is combined with the -t option, zpty tests whether output is available before trying to read. If no output is available, zpty immediately returns the value 1.

zpty -t name

The -t option without the -r option can be used to test whether the command name is still running. It returns a zero value if the command is running and a non-zero value otherwise.

zpty [ -L ]

The last form, without any arguments, is used to list the commands currently defined. If the -L option is given, this is done in the form of calls to the zpty builtin.

The zsh/zselect module makes available one builtin command:

zselect [ -rwe -t timeout -a array ] [ fd ... ] The zselect builtin is a front-end to the `select' system call, which blocks until a file descriptor is ready for reading or writing, or has an error condition, with an optional timeout. If this is not available on your system, the command prints an error message and returns status 2 (normal errors return status 1). For more information, see your systems documentation for select(3). Note there is no connection with the shell builtin of the same name.

Arguments and options may be intermingled in any order. Non-option arguments are file descriptors, which must be decimal integers. By default, file descriptors are to be tested for reading, i.e. zselect will return when data is available to be read from the file descriptor, or more precisely, when a read operation from the file descriptor will not block. After a -r, -w and -e, the given file descriptors are to be tested for reading, writing, or error conditions. These options and an arbitrary list of file descriptors may be given in any order.

(The presence of an `error condition' is not well defined in the documentation for many implementations of the select system call. According to recent versions of the POSIX specification, it is really an exception condition, of which the only standard example is out-of-band data received on a socket. So zsh users are unlikely to find the -e option useful.)

The option `-t timeout' specifies a timeout in hundredths of a second. This may be zero, in which case the file descriptors will simply be polled and zselect will return immediately. It is possible to call zselect with no file descriptors and a non-zero timeout for use as a finer-grained replacement for `sleep'; not, however, the return status is always 1 for a timeout.

The option `-a array' indicates that array should be set to indicate the file descriptor(s) which are ready. If the option is not given, the array reply will be used for this purpose. The array will contain a string similar to the arguments for zselect. For example,

zselect -t 0 -r 0 -w 1

might return immediately with status 0 and $reply containing `-r 0 -w 1' to show that both file descriptors are ready for the requested operations.

The option `-A assoc' indicates that the associative array assoc should be set to indicate the file descriptor(s) which are ready. This option overrides the option -a, nor will reply be modified. The keys of assoc are the file descriptors, and the corresponding values are any of the characters `rwe' to indicate the condition.

The command returns 0 if some file descriptors are ready for reading. If the operation timed out, or a timeout of 0 was given and no file descriptors were ready, or there was an error, it returns status 1 and the array will not be set (nor modified in any way). If there was an error in the select operation the appropriate error message is printed.

The zsh/zutil module only adds some builtins:

zstyle [ -L ]

zstyle [ -e | - | -- ] pattern style strings ...

zstyle -d [ pattern [ styles ... ] ]

zstyle -g name [ pattern [ style ] ]

zstyle -abs context style name [ sep ]

zstyle -Tt context style [ strings ...]

zstyle -m context style pattern This builtin command is used to define and lookup styles. Styles are pairs of names and values, where the values consist of any number of strings. They are stored together with patterns and lookup is done by giving a string, called the `context', which is compared to the patterns. The definition stored for the first matching pattern will be returned.

For ordering of comparisons, patterns are searched from most specific to least specific, and patterns that are equally specific keep the order in which they were defined. A pattern is considered to be more specific than another if it contains more components (substrings separated by colons) or if the patterns for the components are more specific, where simple strings are considered to be more specific than patterns and complex patterns are considered to be more specific than the pattern `*'.

The first form (without arguments) lists the definitions in the order zstyle will test them. If the -L option is given, listing is done in the form of calls to zstyle. Forms with arguments:

zstyle [ - | -- | -e ] pattern style strings ... Defines the given style for the pattern with the strings as the value. If the -e option is given, the strings will be concatenated (separated by spaces) and the resulting string will be evaluated (in the same way as it is done by the eval builtin command) when the style is looked up. In this case the parameter `reply' must be assigned to set the strings returned after the evaluation. Before evaluating the value, reply is unset, and if it is still unset after the evaluation, the style is treated as if it were not set.

zstyle -d [ pattern [ styles ... ] ]

Delete style definitions. Without arguments all definitions are deleted, with a pattern all definitions for that pattern are deleted and if any styles are given, then only those styles are deleted for the pattern.

zstyle -g name [ pattern [ style ] ]

Retrieve a style definition. The name is used as the name of an array in which the results are stored. Without any further arguments, all patterns defined are returned. With a pattern the styles defined for that pattern are returned and with both a pattern and a style, the value strings of that combination is returned.

The other forms can be used to look up or test patterns.

zstyle -s context style name [ sep ] The parameter name is set to the value of the style interpreted as a string. If the value contains several strings they are concatenated with spaces (or with the sep string if that is given) between them.

zstyle -b context style name

The value is stored in name as a boolean, i.e. as the string `yes' if the value has only one string and that string is equal to one of `yes', `true', `on', or `1'. If the value is any other string or has more than one string, the parameter is set to `no'.

zstyle -a context style name

The value is stored in name as an array. If name is declared as an associative array, the first, third, etc. strings are used as the keys and the other strings are used as the values.

zstyle -t context style [ strings ...]

zstyle -T context style [ strings ...] Test the value of a style, i.e. the -t option only returns a status (sets $?). Without any strings the return status is zero if the style is defined for at least one matching pattern, has only one string in its value, and that is equal to one of `true', `yes', `on' or `1'. If any strings are given the status is zero if and only if at least one of the strings is equal to at least one of the strings in the value. If the style is not defined, the status is 2.

The -T option tests the values of the style like -t, but it returns zero (rather than 2) if the style is not defined for any matching pattern.

zstyle -m context style pattern

Match a value. Returns status zero if the pattern matches at least one of the strings in the value.

zformat -f param format specs ...

zformat -a array sep specs ... This builtin provides two different forms of formatting. The first form is selected with the -f option. In this case the format string will be modified by replacing sequences starting with a percent sign in it with strings from the specs. Each spec should be of the form `char:string' which will cause every appearance of the sequence `%char' in format to be replaced by the string. The `%' sequence may also contain optional minimum and maximum field width specifications between the `%' and the `char' in the form `%min.maxc', i.e. the minimum field width is given first and if the maximum field width is used, it has to be preceded by a dot. Specifying a minimum field width makes the result be padded with spaces to the right if the string is shorter than the requested width. Padding to the left can be achieved by giving a negative minimum field width. If a maximum field width is specified, the string will be truncated after that many characters. After all `%' sequences for the given specs have been processed, the resulting string is stored in the parameter param.

The %-escapes also understand ternary expressions in the form used by prompts. The % is followed by a `(' and then an ordinary format specifier character as described above. There may be a set of digits either before or after the `('; these specify a test number, which defaults to zero. Negative numbers are also allowed. An arbitrary delimiter character follows the format specifier, which is followed by a piece of `true' text, the delimiter character again, a piece of `false' text, and a closing parenthesis. The complete expression (without the digits) thus looks like `%(X.text1.text2)', except that the `.' character is arbitrary. The value given for the format specifier in the char:string expressions is evaluated as a mathematical expression, and compared with the test number. If they are the same, text1 is output, else text2 is output. A parenthesis may be escaped in text2 as %). Either of text1 or text2 may contain nested %-escapes.

For example:

zformat -f REPLY "The answer is '%3(c.yes.no)'." c:3

outputs "The answer is 'yes'." to REPLY since the value for the format specifier c is 3, agreeing with the digit argument to the ternary expression.

The second form, using the -a option, can be used for aligning strings. Here, the specs are of the form `left:right' where `left' and `right' are arbitrary strings. These strings are modified by replacing the colons by the sep string and padding the left strings with spaces to the right so that the sep strings in the result (and hence the right strings after them) are all aligned if the strings are printed below each other. All strings without a colon are left unchanged and all strings with an empty right string have the trailing colon removed. In both cases the lengths of the strings are not used to determine how the other strings are to be aligned. The resulting strings are stored in the array.

zregexparse

This implements some internals of the _regex_arguments function.

zparseopts [ -D ] [ -K ] [ -E ] [ -a array ] [ -A assoc ] specs

This builtin simplifies the parsing of options in positional parameters, i.e. the set of arguments given by $*. Each spec describes one option and must be of the form `opt[=array]'. If an option described by opt is found in the positional parameters it is copied into the array specified with the -a option; if the optional `=array' is given, it is instead copied into that array.

Note that it is an error to give any spec without an `=array' unless one of the -a or -A options is used.

Unless the -E option is given, parsing stops at the first string that isn't described by one of the specs. Even with -E, parsing always stops at a positional parameter equal to `-' or `--'.

The opt description must be one of the following. Any of the special characters can appear in the option name provided it is preceded by a backslash.

name

name+ The name is the name of the option without the leading `-'. To specify a GNU-style long option, one of the usual two leading `-' must be included in name; for example, a `--file' option is represented by a name of `-file'.

If a `+' appears after name, the option is appended to array each time it is found in the positional parameters; without the `+' only the last occurrence of the option is preserved.

If one of these forms is used, the option takes no argument, so parsing stops if the next positional parameter does not also begin with `-' (unless the -E option is used).

name:

name:-

name:: If one or two colons are given, the option takes an argument; with one colon, the argument is mandatory and with two colons it is optional. The argument is appended to the array after the option itself.

An optional argument is put into the same array element as the option name (note that this makes empty strings as arguments indistinguishable). A mandatory argument is added as a separate element unless the `:-' form is used, in which case the argument is put into the same element.

A `+' as described above may appear between the name and the first colon.

The options of zparseopts itself are:

-a array As described above, this names the default array in which to store the recognised options.

-A assoc

If this is given, the options and their values are also put into an associative array with the option names as keys and the arguments (if any) as the values.

-D

If this option is given, all options found are removed from the positional parameters of the calling shell or shell function, up to but not including any not described by the specs. This is similar to using the shift builtin.

-K

With this option, the arrays specified with the -a and -A options and with the `=array' forms are kept unchanged when none of the specs for them is used. This allows assignment of default values to them before calling zparseopts.

-E

This changes the parsing rules to not stop at the first string that isn't described by one of the specs. It can be used to test for or (if used together with -D) extract options and their arguments, ignoring all other options and arguments that may be in the positional parameters.

For example,

set -- -a -bx -c y -cz baz -cend
zparseopts a=foo b:=bar c+:=bar

will have the effect of

foo=(-a)
bar=(-b x -c y -c z)

The arguments from `baz' on will not be used.

As an example for the -E option, consider:

set -- -a x -b y -c z arg1 arg2
zparseopts -E -D b:=bar

will have the effect of

bar=(-b y)
set -- -a x -c z arg1 arg2

I.e., the option -b and its arguments are taken from the positional parameters and put into the array bar.