The modules that are bundled with the zsh distribution are:
The zsh/attr module is used for manipulating extended attributes. The -h option causes all commands to operate on symbolic links instead of their targets. The builtins in this module are:
zgetattr and zlistattr allocate memory dynamically. If the attribute or list of attributes grows between the allocation and the call to get them, they return 2. On all other errors, 1 is returned. This allows the calling function to check for this case and retry.
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:
The zsh/clone module makes available one builtin command:
The return status 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:
This does not apply when cloning to an unused vc.
Cloning to a 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.
The parameters ZLS_COLORS and ZLS_COLOURS describe how matches are highlighted. To turn on highlighting an empty value suffices, in which case all the default values given below will be used. The format of the value of these parameters is the same as used by the GNU version of the ls command: a colon-separated list of specifications of the form `name=value'. The name may be one of the following strings, most of which specify file types for which the value will be used. The strings and their default values are:
Apart from these strings, the name may also be an asterisk (`*') followed by any string. The value given for such a string will be used for all files whose name ends with the string. The name may also be an equals sign (`=') followed by a pattern; the EXTENDED_GLOB option will be turned on for evaluation of the pattern. The value given for this pattern will be used for all matches (not just filenames) whose display string are matched by the pattern. Definitions for the form with the leading equal sign take precedence over the values defined for file types, which in turn take precedence over the form with the leading asterisk (file extensions).
The leading-equals form also allows different parts of the displayed strings to be colored differently. For this, the pattern has to use the `(#b)' globbing flag and pairs of parentheses surrounding the parts of the strings that are to be colored differently. In this case the value may consist of more than one color code separated by equal signs. The first code will be used for all parts for which no explicit code is specified and the following codes will be used for the parts matched by the sub-patterns in parentheses. For example, the specification `=(#b)(?)*(?)=0=3=7' will be used for all matches which are at least two characters long and will use the code `3' for the first character, `7' for the last character and `0' for the rest.
All three forms of name may be preceded by a pattern in parentheses. If this is given, the value will be used only for matches in groups whose names are matched by the pattern given in the parentheses. For example, `(g*)m*=43' highlights all matches beginning with `m' in groups whose names begin with `g' using the color code `43'. In case of the `lc', `rc', and `ec' codes, the group pattern is ignored.
Note also that all patterns are tried in the order in which they appear in the parameter value until the first one matches which is then used. Patterns may be matched against completions, descriptions (possibly with spaces appended for padding), or lines consisting of a completion followed by a description. For consistent coloring it may be necessary to use more than one pattern or a pattern with backreferences.
When printing a match, the code prints the value of lc, the value for the file-type or the last matching specification with a `*', the value of rc, the string to display for the match itself, and then the value of ec if that is defined or the values of lc, no, and rc if ec is not defined.
The default values are ISO 6429 (ANSI) compliant and can be used on vt100 compatible terminals such as xterms. On monochrome terminals the default values will have no visible effect. The colors function from the contribution can be used to get associative arrays containing the codes for ANSI terminals (see the section `Other Functions' in zshcontrib(1)). For example, after loading colors, one could use `$color[red]' to get the code for foreground color red and `$color[bg-green]' for the code for background color green.
If the completion system invoked by compinit is used, these parameters should not be set directly because the system controls them itself. Instead, the list-colors style should be used (see the section `Completion System Configuration' in zshcompsys(1)).
If the parameter LISTPROMPT is set, the completion code will not ask if the list should be shown. Instead it immediately starts displaying the list, stopping after the first screenful, showing the prompt at the bottom, waiting for a keypress after temporarily switching to the listscroll keymap. Some of the zle functions have a special meaning while scrolling lists:
Every other character stops listing and immediately processes the key as usual. Any key that is not bound in the listscroll keymap or that is bound to undefined-key is looked up in the keymap currently selected.
As for the ZLS_COLORS and ZLS_COLOURS parameters, LISTPROMPT should not be set directly when using the shell function based completion system. Instead, the list-prompt style should be used.
Menu selection can be invoked directly by the widget menu-select defined by this module. This is a standard ZLE widget that can be bound to a key in the usual way as described in zshzle(1).
Alternatively, the parameter MENUSELECT can be set to an integer, which gives the minimum number of matches that must be present before menu selection is automatically turned on. This second method requires that menu completion be started, either directly from a widget such as menu-complete, or due to one of the options MENU_COMPLETE or AUTO_MENU being set. If MENUSELECT is set, but is 0, 1 or empty, menu selection will always be started during an ambiguous menu completion.
When using the completion system based on shell functions, the MENUSELECT parameter should not be used (like the ZLS_COLORS and ZLS_COLOURS parameters described above). Instead, the menu style should be used with the select=... keyword.
After menu selection is started, the matches will be listed. If there are more matches than fit on the screen, only the first screenful is shown. The matches to insert into the command line can be selected from this list. In the list one match is highlighted using the value for ma from the ZLS_COLORS or ZLS_COLOURS parameter. The default value for this is `7' which forces the selected match to be highlighted using standout mode on a vt100-compatible terminal. If neither ZLS_COLORS nor ZLS_COLOURS is set, the same terminal control sequence as for the `%S' escape in prompts is used.
If there are more matches than fit on the screen and the parameter MENUPROMPT is set, its value will be shown below the matches. It supports the same escape sequences as LISTPROMPT, but the number of the match or line shown will be that of the one where the mark is placed. If its value is the empty string, a default prompt will be used.
The MENUSCROLL parameter can be used to specify how the list is scrolled. If the parameter is unset, this is done line by line, if it is set to `0' (zero), the list will scroll half the number of lines of the screen. If the value is positive, it gives the number of lines to scroll and if it is negative, the list will be scrolled the number of lines of the screen minus the (absolute) value.
As for the ZLS_COLORS, ZLS_COLOURS and LISTPROMPT parameters, neither MENUPROMPT nor MENUSCROLL should be set directly when using the shell function based completion system. Instead, the select-prompt and select-scroll styles should be used.
The completion code sometimes decides not to show all of the matches in the list. These hidden matches are either matches for which the completion function which added them explicitly requested that they not appear in the list (using the -n option of the compadd builtin command) or they are matches which duplicate a string already in the list (because they differ only in things like prefixes or suffixes that are not displayed). In the list used for menu selection, however, even these matches are shown so that it is possible to select them. To highlight such matches the hi and du capabilities in the ZLS_COLORS and ZLS_COLOURS parameters are supported for hidden matches of the first and second kind, respectively.
Selecting matches is done by moving the mark around using the zle movement functions. When not all matches can be shown on the screen at the same time, the list will scroll up and down when crossing the top or bottom line. The following zle functions have special meaning during menu selection. Note that the following always perform the same task within the menu selection map and cannot be replaced by user defined widgets, nor can the set of functions be extended:
All movement functions wrap around at the edges; any other zle function not listed leaves menu selection and executes that function. It is possible to make widgets in the above list do the same by using the form of the widget with a `.' in front. For example, the widget `.accept-line' has the effect of leaving menu selection and accepting the entire command line.
During this selection the widget uses the keymap menuselect. Any key that is not defined in this keymap or that is bound to undefined-key is looked up in the keymap currently selected. This is used to ensure that the most important keys used during selection (namely the cursor keys, return, and TAB) have sensible defaults. However, keys in the menuselect keymap can be modified directly using the bindkey builtin command (see zshmodules(1)). For example, to make the return key leave menu selection without accepting the match currently selected one could call
bindkey -M menuselect '^M' send-break
after loading the zsh/complist module.
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:
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 four parameters as its arguments. This will step through the different sets of matches and store the value of compstate[list] in the first scalar, the options for compadd in the second array, the matches in the third array, and the strings to be displayed in the completion listing in the fourth array. The arrays may then be directly given to compadd to register the matches with the completion code.
The return status is non-zero in case of an error and zero otherwise.
The zsh/curses module makes available one builtin command and various parameters.
The subcommand addwin creates a window with nlines lines and ncols columns. Its upper left corner will be placed at row begin_y and column begin_x of the screen. targetwin is a string and refers to the name of a window that is not currently assigned. Note in particular the curses convention that vertical values appear before horizontal values.
If addwin is given an existing window as the final argument, the new window is created as a subwindow of parentwin. This differs from an ordinary new window in that the memory of the window contents is shared with the parent's memory. Subwindows must be deleted before their parent. Note that the coordinates of subwindows are relative to the screen, not the parent, as with other windows.
Use the subcommand delwin to delete a window created with addwin. Note that end does not implicitly delete windows, and that delwin does not erase the screen image of the window.
The window corresponding to the full visible screen is called stdscr; it always exists after `zcurses init' and cannot be delete with delwin.
The subcommand refresh will refresh window targetwin; this is necessary to make any pending changes (such as characters you have prepared for output with char) visible on the screen. refresh without an argument causes the screen to be cleared and redrawn. If multiple windows are given, the screen is updated once at the end.
The subcommand touch marks the targetwins listed as changed. This is necessary before refreshing windows if a window that was in front of another window (which may be stdscr) is deleted.
The subcommand move moves the cursor position in targetwin to new coordinates new_y and new_x. Note that the subcommand string (but not the subcommand char) advances the cursor position over the characters added.
The subcommand clear erases the contents of targetwin. One (and no more than one) of three options may be specified. With the option redraw, in addition the next refresh of targetwin will cause the screen to be cleared and repainted. With the option eol, targetwin is only cleared to the end of the current cursor line. With the option bot, targetwin is cleared to the end of the window, i.e everything to the right and below the cursor is cleared.
The subcommand position writes various positions associated with targetwin into the array named array. These are, in order:
Outputting characters and strings are achieved by char and string respectively.
To draw a border around window targetwin, use border. Note that the border is not subsequently handled specially: in other words, the border is simply a set of characters output at the edge of the window. Hence it can be overwritten, can scroll off the window, etc.
The subcommand attr will set targetwin's attributes or foreground/background color pair for any successive character output. Each attribute given on the line may be prepended by a + to set or a - to unset that attribute; + is assumed if absent. The attributes supported are blink, bold, dim, reverse, standout, and underline.
Each fg_col/bg_col attribute (to be read as `fg_col on bg_col') sets the foreground and background color for character output. The color default is sometimes available (in particular if the library is ncurses), specifying the foreground or background color with which the terminal started. The color pair default/default is always available. To use more than the 8 named colors (red, green, etc.) construct the fg_col/bg_col pairs where fg_col and bg_col are decimal integers, e.g 128/200. The maximum color value is 254 if the terminal supports 256 colors.
bg overrides the color and other attributes of all characters in the window. Its usual use is to set the background initially, but it will overwrite the attributes of any characters at the time when it is called. In addition to the arguments allowed with attr, an argument @char specifies a character to be shown in otherwise blank areas of the window. Owing to limitations of curses this cannot be a multibyte character (use of ASCII characters only is recommended). As the specified set of attributes override the existing background, turning attributes off in the arguments is not useful, though this does not cause an error.
The subcommand scroll can be used with on or off to enabled or disable scrolling of a window when the cursor would otherwise move below the window due to typing or output. It can also be used with a positive or negative integer to scroll the window up or down the given number of lines without changing the current cursor position (which therefore appears to move in the opposite direction relative to the window). In the second case, if scrolling is off it is temporarily turned on to allow the window to be scrolled.
The subcommand input reads a single character from the window without echoing it back. If param is supplied the character is assigned to the parameter param, else it is assigned to the parameter REPLY.
If both param and kparam are supplied, the key is read in `keypad' mode. In this mode special keys such as function keys and arrow keys return the name of the key in the parameter kparam. The key names are the macros defined in the curses.h or ncurses.h with the prefix `KEY_' removed; see also the description of the parameter zcurses_keycodes below. Other keys cause a value to be set in param as before. On a successful return only one of param or kparam contains a non-empty string; the other is set to an empty string.
If mparam is also supplied, input attempts to handle mouse input. This is only available with the ncurses library; mouse handling can be detected by checking for the exit status of `zcurses mouse' with no arguments. If a mouse button is clicked (or double- or triple-clicked, or pressed or released with a configurable delay from being clicked) then kparam is set to the string MOUSE, and mparam is set to an array consisting of the following elements:
Not all mouse events may be passed through to the terminal window; most terminal emulators handle some mouse events themselves. Note that the ncurses manual implies that using input both with and without mouse handling may cause the mouse cursor to appear and disappear.
The subcommand mouse can be used to configure the use of the mouse. There is no window argument; mouse options are global. `zcurses mouse' with no arguments returns status 0 if mouse handling is possible, else status 1. Otherwise, the possible arguments (which may be combined on the same command line) are as follows. delay num sets the maximum delay in milliseconds between press and release events to be considered as a click; the value 0 disables click resolution, and the default is one sixth of a second. motion proceeded by an optional `+' (the default) or - turns on or off reporting of mouse motion in addition to clicks, presses and releases, which are always reported. However, it appears reports for mouse motion are not currently implemented.
The subcommand timeout specifies a timeout value for input from targetwin. If intval is negative, `zcurses input' waits indefinitely for a character to be typed; this is the default. If intval is zero, `zcurses input' returns immediately; if there is typeahead it is returned, else no input is done and status 1 is returned. If intval is positive, `zcurses input' waits intval milliseconds for input and if there is none at the end of that period returns status 1.
The subcommand querychar queries the character at the current cursor position. The return values are stored in the array named param if supplied, else in the array reply. The first value is the character (which may be a multibyte character if the system supports them); the second is the color pair in the usual fg_col/bg_col notation, or 0 if color is not supported. Any attributes other than color that apply to the character, as set with the subcommand attr, appear as additional elements.
The subcommand resize resizes stdscr and all windows to given dimensions (windows that stick out from the new dimensions are resized down). The underlying curses extension (resize_term call) can be unavailable. To verify, zeroes can be used for height and width. If the result of the subcommand is 0, resize_term is available (2 otherwise). Tests show that resizing can be normally accomplished by calling zcurses end and zcurses refresh. The resize subcommand is provided for versatility. Multiple system configurations have been checked and zcurses end and zcurses refresh are still needed for correct terminal state after resize. To invoke them with resize, use endwin argument. Using nosave argument will cause new terminal state to not be saved internally by zcurses. This is also provided for versatility and should normally be not needed.
The zsh/datetime module makes available one builtin command:
In most implementations of strftime any timezone in the timestring is ignored and the local timezone declared by the TZ environment variable is used; other parameters are set to zero if not present.
If timestring does not match format the command returns status 1 and prints an error message. If timestring matches format but not all characters in timestring were used, the conversion succeeds but also prints an error message.
If either of the system functions strptime or mktime is not available, status 2 is returned and an error message is printed.
Note that depending on the system's declared integral time type, strftime may produce incorrect results for epoch times greater than 2147483647 which corresponds to 2038-01-19 03:14:07 +0000.
The zsh/datetime module makes available several parameters; all are readonly:
for secs nsecs in $epochtime; do ... done
The zsh/db/gdbm module is used to create "tied" associative arrays that interface to database files. If the GDBM interface is not available, the builtins defined by this module will report an error. This module is also intended as a prototype for creating additional database interfaces, so the ztie builtin may move to a more generic module in the future.
The builtins in this module are:
local -A sampledb ztie -d db/gdbm -f sample.gdbm sampledb
The -r option opens the database file for reading only, creating a parameter with the readonly attribute. Without this option, using `ztie' on a file for which the user does not have write permission is an error. If writable, the database is opened synchronously so fields changed in arrayname are immediately written to filename.
Changes to the file modes filename after it has been opened do not alter the state of arrayname, but `typeset -r arrayname' works as expected.
This happens automatically if the parameter is explicitly unset or its local scope (function) ends. Note that a readonly parameter may not be explicitly unset, so the only way to unset a global parameter created with `ztie -r' is to use `zuntie -u'.
The fields of an associative array tied to GDBM are neither cached nor otherwise stored in memory, they are read from or written to the database on each reference. Thus, for example, the values in a readonly array may be changed by a second writer of the same database file.
The zsh/deltochar module makes available two ZLE functions:
The zsh/example module makes available one builtin command:
The purpose of the module is to serve as an example of how to write a module.
The zsh/files module makes available some common commands for file manipulation as builtins; these commands are probably not needed for many normal situations but can be useful in emergency recovery situations with constrained resources. The commands do not implement all features now required by relevant standards committees.
For all commands, a variant beginning zf_ is also available and loaded automatically. Using the features capability of zmodload will let you load only those names you want. Note that it's possible to load only the builtins with zsh-specific names using the following command:
zmodload -m -F zsh/files b:zf_\*
The commands loaded by default are:
The specified mode must be in octal.
The -R option causes chmod to recursively descend into directories, changing the mode of all files in the directory after changing the mode of the directory itself.
The -s option is a zsh extension to chmod functionality. It enables paranoid behaviour, intended to avoid security problems involving a chmod being tricked into affecting files other than the ones intended. It will refuse to follow symbolic links, so that (for example) ``chmod 600 /tmp/foo/passwd'' can't accidentally chmod /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 chmod of a deep directory tree can't end up recursively chmoding /usr as a result of directories being moved up the tree.
The user-spec can be in four forms:
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).
If the target is a symbolic link, the -h option causes chown to set the ownership of the link instead of its target.
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.
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.
The -h and -n options are identical and both exist for compatibility; either one indicates that if the target is a symlink then it should not be dereferenced. Typically this is used in combination with -sf so that if an existing link points to a directory then it will be removed, instead of followed. If this option is used with multiple filenames and the target is a symbolic link pointing to a directory then the result is an error.
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.
Normally, rm will not remove directories (except with the -R or -r options). 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 and -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 and -r options cause 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.
The zsh/langinfo module makes available one parameter:
Your implementation may support a number of the following keys:
CODESET, D_T_FMT, D_FMT, T_FMT, RADIXCHAR, THOUSEP, YESEXPR, NOEXPR, CRNCYSTR, ABDAY_{1..7}, DAY_{1..7}, ABMON_{1..12}, MON_{1..12}, T_FMT_AMPM, AM_STR, PM_STR, ERA, ERA_D_FMT, ERA_D_T_FMT, ERA_T_FMT, ALT_DIGITS
The zsh/mapfile module provides one special associative array parameter of the same name.
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 effect as the glob operator *(D), since files beginning with a dot are not special. Care must be taken with expressions such as rm ${(k)mapfile}, which will delete every file in the current directory without the usual `rm *' test.
The parameter mapfile may be made read-only; in that case, files referenced may not be written or deleted.
A file may conveniently be read into an array as one line per element with the form `array=("${(f@)mapfile[filename]}")'. The double quotes and the `@' are necessary to prevent empty lines from being removed. Note that if the file ends with a newline, the shell will split on the final newline, generating an additional empty field; this can be suppressed by using `array=("${(f@)${mapfile[filename]%$'\n'}}")'.
Although reading and writing of the file in question is efficiently handled, zsh's internal memory management may be arbitrarily baroque; however, mapfile is usually very much more efficient than anything involving a loop. Note in particular that the whole contents of the file will always reside physically in memory when accessed (possibly multiple times, due to standard parameter substitution operations). In particular, this means handling of sufficiently long files (greater than the machine's swap space, or than the range of the pointer type) will be incorrect.
No errors are printed or flagged for non-existent, unreadable, or unwritable files, as the parameter mechanism is too low in the shell execution hierarchy to make this convenient.
It is unfortunate that the mechanism for loading modules does not yet allow the user to specify the name of the shell parameter to be given the special behaviour.
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, log2, 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 functions min, max, and sum are defined not in this module but in the zmathfunc autoloadable function, described in the section `Mathematical Functions' in zshcontrib(1).
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/nearcolor module replaces colours specified as hex triplets with the nearest colour in the 88 or 256 colour palettes that are widely used by terminal emulators. By default, 24-bit true colour escape codes are generated when colours are specified using hex triplets. These are not supported by all terminals. The purpose of this module is to make it easier to define colour preferences in a form that can work across a range of terminal emulators.
Aside from the default colour, the ANSI standard for terminal escape codes provides for eight colours. The bright attribute brings this to sixteen. These basic colours are commonly used in terminal applications due to being widely supported. Expanded 88 and 256 colour palettes are also common and, while the first sixteen colours vary somewhat between terminals and configurations, these add a generally consistent and predictable set of colours.
In order to use the zsh/nearcolor module, it only needs to be loaded. Thereafter, whenever a colour is specified using a hex triplet, it will be compared against each of the available colours and the closest will be selected. The first sixteen colours are never matched in this process due to being unpredictable.
It isn't possible to reliably detect support for true colour in the terminal emulator. It is therefore recommended to be selective in loading the zsh/nearcolor module. For example, the following checks the COLORTERM environment variable:
[[ $COLORTERM = *(24bit|truecolor)* ]] || zmodload zsh/nearcolor
Note that some terminals accept the true color escape codes but map them internally to a more limited palette in a similar manner to the zsh/nearcolor module.
The zsh/newuser module is loaded at boot if it is available, the RCS option is set, and the PRIVILEGED option is not set (all three are true by default). This takes place immediately after commands in the global zshenv file (typically /etc/zshenv), if any, have been executed. If the module is not available it is silently ignored by the shell; the module may safely be removed from $MODULE_PATH by the administrator if it is not required.
On loading, the module tests if any of the start-up files .zshenv, .zprofile, .zshrc or .zlogin exist in the directory given by the environment variable ZDOTDIR, or the user's home directory if that is not set. The test is not performed and the module halts processing if the shell was in an emulation mode (i.e. had been invoked as some other shell than zsh).
If none of the start-up files were found, the module then looks for the file newuser first in a sitewide directory, usually the parent directory of the site-functions directory, and if that is not found the module searches in a version-specific directory, usually the parent of the functions directory containing version-specific functions. (These directories can be configured when zsh is built using the --enable-site-scriptdir=dir and --enable-scriptdir=dir flags to configure, respectively; the defaults are prefix/share/zsh and prefix/share/zsh/$ZSH_VERSION where the default prefix is /usr/local.)
If the file newuser is found, it is then sourced in the same manner as a start-up file. The file is expected to contain code to install start-up files for the user, however any valid shell code will be executed.
The zsh/newuser module is then unconditionally unloaded.
Note that it is possible to achieve exactly the same effect as the zsh/newuser module by adding code to /etc/zshenv. The module exists simply to allow the shell to make arrangements for new users without the need for intervention by package maintainers and system administrators.
The script supplied with the module invokes the shell function zsh-newuser-install. This may be invoked directly by the user even if the zsh/newuser module is disabled. Note, however, that if the module is not installed the function will not be installed either. The function is documented in the section User Configuration Functions in zshcontrib(1).
The zsh/parameter module gives access to some of the internal hash tables used by the shell by defining some special parameters.
For an autoloaded function that has already been loaded, or marked for autoload with an absolute path, or that has had its path resolved with `functions -r', this is the file found for autoloading, resolved to an absolute path.
For a function defined within the body of a script or sourced file, this is the name of that file. In this case, this is the exact path originally used to that file, which may be a relative path.
For any other function, including any defined at an interactive prompt or an autoload function whose path has not yet been resolved, this is the empty string. However, the hash element is reported as defined just so long as the function is present: the keys to this hash are the same as those to $functions.
Setting or unsetting keys in this array is not possible.
The keys of the associative arrays are usually valid job numbers, and these are the values output with, for example, ${(k)jobdirs}. Non-numeric job references may be used when looking up a value; for example, ${jobdirs[%+]} refers to the current job.
Handling of the keys of the associative array is as described for jobdirs above.
Handling of the keys of the associative array is as described for jobdirs above.
For functions autoloaded from a file in native zsh format, where only the body of the function occurs in the file, or for files that have been executed by the source or `.' builtins, the trace information is shown as filename:0, since the entire file is the definition. The source file name is resolved to an absolute path when the function is loaded or the path to it otherwise resolved.
Most users will be interested in the information in the funcfiletrace array instead.
The standard shell array zsh_eval_context can be used to determine the type of shell construct being executed at each depth: note, however, that is in the opposite order, with the most recent item last, and it is more detailed, for example including an entry for toplevel, the main shell code being executed either interactively or from a script, which is not present in $funcstack.
The zsh/pcre module makes some commands available as builtins:
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. Option -s makes the dot metacharacter match all characters, including those that indicate newline.
Upon successful match, 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. Similarly, the variable MATCH will be set to the entire matched portion of the string, unless the -v option is given, in which case the variable var will be set. No variables are altered if there is no successful match. A -n option starts searching for a match from the byte offset position in string. If the -b option is given, the variable ZPCRE_OP will be set to an offset pair string, representing the byte offset positions of the entire matched portion within the string. For example, a ZPCRE_OP set to "32 45" indicates that the matched portion began on byte offset 32 and ended on byte offset 44. Here, byte offset position 45 is the position directly after the matched portion. Keep in mind that the byte position isn't necessarily the same as the character position when UTF-8 characters are involved. Consequently, the byte offset positions are only to be relied on in the context of using them for subsequent searches on string, using an offset position as an argument to the -n option. This is mostly used to implement the "find all non-overlapping matches" functionality.
A simple example of "find all non-overlapping matches":
string="The following zip codes: 78884 90210 99513"
pcre_compile -m "\d{5}"
accum=()
pcre_match -b -- $string
while [[ $? -eq 0 ]] do
b=($=ZPCRE_OP)
accum+=$MATCH
pcre_match -b -n $b[2] -- $string
done
print -l $accum
The zsh/pcre module makes available the following test condition:
For example,
[[ "$text" -pcre-match ^d+$ ]] && print text variable contains only "d's".
If the REMATCH_PCRE option is set, the =~ operator is equivalent to -pcre-match, and the NO_CASE_MATCH option may be used. Note that NO_CASE_MATCH never applies to the pcre_match builtin, instead use the -i switch of pcre_compile.
The zsh/param/private module is used to create parameters whose scope is limited to the current function body, and not to other functions called by the current function.
This module provides a single autoloaded builtin:
If used at the top level (outside a function scope), private creates a normal parameter in the same manner as declare or typeset. A warning about this is printed if WARN_CREATE_GLOBAL is set (zshoptions(1)). Used inside a function scope, private creates a local parameter similar to one declared with local, except having special properties noted below.
Special parameters which expose or manipulate internal shell state, such as ARGC, argv, COLUMNS, LINES, UID, EUID, IFS, PROMPT, RANDOM, SECONDS, etc., cannot be made private unless the `-h' option is used to hide the special meaning of the parameter. This may change in the future.
As with other typeset equivalents, private is both a builtin and a reserved word, so arrays may be assigned with parenthesized word list name=(value...) syntax. However, the reserved word `private' is not available until zsh/param/private is loaded, so care must be taken with order of execution and parsing for function definitions which use private. To compensate for this, the module also adds the option `-P' to the `local' builtin to declare private parameters.
For example, this construction fails if zsh/param/private has not yet been loaded when `bad_declaration' is defined:
bad_declaration() {
zmodload zsh/param/private
private array=( one two three )
}
This construction works because local is already a keyword, and the module is loaded before the statement is executed:
good_declaration() {
zmodload zsh/param/private
local -P array=( one two three )
}
The following is usable in scripts but may have trouble with autoload:
zmodload zsh/param/private
iffy_declaration() {
private array=( one two three )
}
The private builtin may always be used with scalar assignments and for declarations without assignments.
Parameters declared with private have the following properties:
Note that this differs from the static scope defined by compiled languages derived from C, in that the a new call to the same function creates a new scope, i.e., the parameter is still associated with the call stack rather than with the function definition. It differs from ksh `typeset -S' because the syntax used to define the function has no bearing on whether the parameter scope is respected.
The zsh/regex module makes available the following test condition:
For example,
[[ alphabetical -regex-match ^a([^a]+)a([^a]+)a ]] && print -l $MATCH X $match
If the option REMATCH_PCRE is not set, then the =~ operator will automatically load this module as needed and will invoke the -regex-match operator.
If BASH_REMATCH is set, then the array BASH_REMATCH will be set instead of MATCH and match.
The zsh/sched module makes available one builtin command and one parameter.
With no arguments, prints the list of scheduled commands. If the scheduled command has the -o flag set, this is shown at the start of the command.
With the argument `-item', removes the given item from the list. The numbering of the list is continuous and entries are in time order, so the numbering can change when entries are added or deleted.
Commands are executed either immediately before a prompt, or while the shell's line editor is waiting for input. In the latter case it is useful to be able to produce output that does not interfere with the line being edited. Providing the option -o causes the shell to clear the command line before the event and redraw it afterwards. This should be used with any scheduled event that produces visible output to the terminal; it is not needed, for example, with output that updates a terminal emulator's title bar.
To effect changes to the editor buffer when an event executes, use the `zle' command with no arguments to test whether the editor is active, and if it is, then use `zle widget' to access the editor via the named widget.
The sched builtin is not made available by default when the shell starts in a mode emulating another shell. It can be made available with the command `zmodload -F zsh/sched b:sched'.
The sched builtin should be used for manipulating the events. Note that this will have an immediate effect on the contents of the array, so that indices may become invalid.
The zsh/net/socket module makes available one builtin command:
If -d is specified, its argument will be taken as the target file descriptor for the connection.
In order to elicit more verbose output, use -v.
File descriptors can be closed with normal shell syntax when no longer needed, for example:
exec {REPLY}>&-
If -d is specified, its argument will be taken as the target file descriptor for the connection.
In order to elicit more verbose output, use -v.
If -d is specified, its argument will be taken as the target file descriptor for the connection.
If -t is specified, zsocket will return if no incoming connection is pending. Otherwise it will wait for one.
In order to elicit more verbose output, use -v.
The zsh/stat module makes available one builtin command under two possible names:
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:
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:
The zsh/system module makes available various builtin commands and parameters.
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 status 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 status of 1 indicates an error in the parameters, and a return status of 2 indicates the error name was not recognised (no message is printed for this).
The -o option allows various system specific options to be specified as a comma-separated list. The following is a list of possible options. Note that, depending on the system, some may not be available.
To close the file, use one of the following:
exec {fd}<&-
exec {fd}>&-
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 statuses are
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.
In the first form the named file, which must already exist, is locked by opening a file descriptor to the file and applying a lock to the file descriptor. The lock terminates when the shell process that created the lock exits; it is therefore often convenient to create file locks within subshells, since the lock is automatically released when the subshell exits. Note that use of the print builtin with the -u option will, as a side effect, release the lock, as will redirection to the file in the shell holding the lock. To work around this use a subshell, e.g. `(print message) >> file'. Status 0 is returned if the lock succeeds, else status 1.
In the second form the file descriptor given by the arithmetic expression fd_expr is closed, releasing a lock. The file descriptor can be queried by using the `-f var' form during the lock; on a successful lock, the shell variable var is set to the file descriptor used for locking. The lock will be released if the file descriptor is closed by any other means, for example using `exec {var}>&-'; however, the form described here performs a safety check that the file descriptor is in use for file locking.
By default the shell waits indefinitely for the lock to succeed. The option -t timeout specifies a timeout for the lock in seconds; currently this must be an integer. The shell will attempt to lock the file once a second during this period. If the attempt times out, status 2 is returned.
If the option -e is given, the file descriptor for the lock is preserved when the shell uses exec to start a new process; otherwise it is closed at that point and the lock released.
If the option -r is given, the lock is only for reading, otherwise it is for reading and writing. The file descriptor is opened accordingly.
Note that aliases for errors are not handled; only the canonical name is used.
The zsh/net/tcp module makes available one builtin command:
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:
If -d is specified, its argument will be taken as the target file descriptor for the connection.
In order to elicit more verbose output, use -v.
If -d is specified, its argument will be taken as the target file descriptor for the connection.
In order to elicit more verbose output, use -v.
If -d is specified, its argument will be taken as the target file descriptor for the connection.
If -t is specified, ztcp will return if no incoming connection is pending. Otherwise it will wait for one.
In order to elicit more verbose output, use -v.
Normally, sockets registered by zftp (see zshmodules(1) ) cannot be closed this way. In order to force such a socket closed, use -f.
In order to elicit more verbose output, use -v.
On host1,
zmodload zsh/net/tcp ztcp -l 5123 listenfd=$REPLY ztcp -a $listenfd fd=$REPLY
Now create a connection from host2 (which may, of course, be the same machine):
zmodload zsh/net/tcp ztcp host1 5123 fd=$REPLY
Now on each host, $fd contains a file descriptor for talking to the other. For example, on host1:
print This is a message >&$fd
read -r line <&$fd; print -r - $line
To tidy up, on host1:
ztcp -c $listenfd ztcp -c $fd
ztcp -c $fd
The zsh/termcap module makes available one builtin command:
The zsh/termcap module makes available one parameter:
The zsh/terminfo module makes available one builtin command:
The zsh/terminfo module makes available one parameter:
The zsh/zftp module makes available one builtin command:
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.
If IPv6 addresses in colon format are used, the host should be surrounded by quoted square brackets to distinguish it from the port, for example '[fe80::203:baff:fe02:8b56]'. For consistency this is allowed with all forms of host.
Remaining arguments are passed to the login subcommand. Note that if no arguments beyond host are supplied, open will not automatically call login. If no arguments at all are supplied, open will use the parameters set by the params subcommand.
After a successful open, the shell variables ZFTP_HOST, ZFTP_PORT, ZFTP_IP and ZFTP_SYSTEM are available; see `Variables' below.
After a successful login, the shell variables ZFTP_USER, ZFTP_ACCOUNT and ZFTP_PWD are available; see `Variables' below.
This command may be re-issued when a user is already logged in, and the server will first be reinitialized for a new user.
Any of the parameters may be specified as a `?', which may need to be quoted to protect it from shell expansion. In this case, the appropriate parameter will be read from stdin as with the login subcommand, including special handling of password. If the `?' is followed by a string, that is used as the prompt for reading the parameter instead of the default message (any necessary punctuation and whitespace should be included at the end of the prompt). The first letter of the parameter (only) may be quoted with a `\'; hence an argument "\\$word" guarantees that the string from the shell parameter $word will be treated literally, whether or not it begins with a `?'.
If instead a single `-' is given, the existing parameters, if any, are deleted. In that case, calling open with no arguments will cause an error.
The list of parameters is not deleted after a close, however it will be deleted if the zsh/zftp module is unloaded.
For example,
zftp params ftp.elsewhere.xx juser '?Password for juser: '
will store the host ftp.elsewhere.xx and the user juser and then prompt the user for the corresponding password with the given prompt.
The FTP default for a transfer is ASCII. However, if zftp finds that the remote host is a UNIX machine with 8-bit byes, it will automatically switch to using binary for file transfers upon open. This can subsequently be overridden.
The transfer type is only passed to the remote host when a data connection is established; this command involves no network overhead.
Not all servers support the commands for retrieving this information. In that case, the remote command will print nothing and return status 2, compared with status 1 for a file not found.
The local command (but not remote) may be used with no arguments, in which case the information comes from examining file descriptor zero. This is the same file as seen by a put command with no further redirection.
Each session remembers the status of the connection, the set of connection-specific shell parameters (the same set as are unset when a connection closes, as given in the description of close), and any user parameters specified with the params subcommand. Changing to a previous session restores those values; changing to a new session initialises them in the same way as if zftp had just been loaded. The name of the current session is given by the parameter ZFTP_SESSION.
In the unlikely event that your system does not have the appropriate conversion functions, this appears in network byte order. If your system is little-endian, the port then consists of two swapped bytes and the standard port will be reported as 5376. In that case, numeric ports passed to zftp open will also need to be in this format.
If ZFTP_PREFS is not set when zftp is loaded, it will be set to a default of `PS', i.e. use passive mode if available, otherwise fall back to sendport mode.
It should be noted that, for unknown reasons, the reply `Service not available', which forces termination of a connection, is classified as 421, i.e. `transient negative', an interesting interpretation of the word `transient'.
The code 0 is special: it indicates that all but the last line of multiline replies read from the server will be printed to standard error in a processed format. By convention, servers use this mechanism for sending information for the user to read. The appropriate reply code, if it matches the same response, takes priority.
If ZFTP_VERBOSE is not set when zftp is loaded, it will be set to the default value 450, i.e., messages destined for the user and all errors will be printed. A null string is valid and specifies that no messages should be printed.
When it is called with a transfer in progress, the following additional shell parameters are set:
The function is initially called with ZFTP_TRANSFER set appropriately and ZFTP_COUNT set to zero. After the transfer is finished, the function will be called one more time with ZFTP_TRANSFER set to GF or PF, in case it wishes to tidy up. It is otherwise never called twice with the same value of ZFTP_COUNT.
Sometimes the progress meter may cause disruption. It is up to the user to decide whether the function should be defined and to use unfunction when necessary.
A connection may not be opened in the left hand side of a pipe as this occurs in a subshell and the file information is not updated in the main shell. In the case of type or mode changes or closing the connection in a subshell, the information is returned but variables are not updated until the next call to zftp. Other status changes in subshells will not be reflected by changes to the variables (but should be otherwise harmless).
Deleting sessions while a zftp command is active in the background can have unexpected effects, even if it does not use the session being deleted. This is because all shell subprocesses share information on the state of all connections, and deleting a session changes the ordering of that information.
On some operating systems, the control connection is not valid after a fork(), so that operations in subshells, on the left hand side of a pipeline, or in the background are not possible, as they should be. This is presumably a bug in the operating system.
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)).
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.
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]', then the number of calls made to the function. The next three columns list the time in milliseconds spent in the function and its descendants, the average time in milliseconds spent in the function and its descendants per call and the percentage of time spent in all shell functions used in this function and its descendants. 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 descendants. 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 descendants 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 descendants 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:
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.
The shell parameter REPLY is set to the file descriptor assigned to the master side of the pseudo-terminal. This allows the terminal to be monitored with ZLE descriptor handlers (see zshzle(1)) or manipulated with sysread and syswrite (see THE ZSH/SYSTEM MODULE in zshmodules(1)). Warning: Use of sysread and syswrite is not recommended; use zpty -r and zpty -w unless you know exactly what you are doing.
If no string is 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. The exact input is always copied: the -n option is not applied.
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.
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 status 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 status is zero if the string read matches the pattern, or if the command has exited but at least one character could still be read. If the option -m is present, the return status is zero only if the pattern matches. 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 status is non-zero.
In all cases, the return status 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 status 1. When used with a pattern, the behaviour on a failed poll is similar to when the command has exited: the return value is zero if at least one character could still be read even if the pattern failed to match.
The zsh/zselect module makes available one builtin command:
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'; note, 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 $reply containing `-r 0 -w 1' to show that both file descriptors are ready for the requested operations.
The option `-A assoc' indicates that the associative array assoc should be set to indicate the file descriptor(s) which are ready. This option overrides the option -a, nor will reply be modified. The keys of assoc are the file descriptors, and the corresponding values are any of the characters `rwe' to indicate the condition.
The command returns status 0 if some file descriptors are ready for reading. If the operation timed out, or a timeout of 0 was given and no file descriptors were ready, or there was an error, it returns status 1 and the array will not be set (nor modified in any way). If there was an error in the select operation the appropriate error message is printed.
The zsh/zutil module only adds some builtins:
A pattern is considered to be more specific than another if it contains more components (substrings separated by colons) or if the patterns for the components are more specific, where simple strings are considered to be more specific than patterns and complex patterns are considered to be more specific than the pattern `*'. A `*' in the pattern will match zero or more characters in the context; colons are not treated specially in this regard. If two patterns are equally specific, the tie is broken in favour of the pattern that was defined first.
Example
For example, to define your preferred form of precipitation depending on which city you're in, you might set the following in your zshrc:
zstyle ':weather:europe:*' preferred-precipitation rain zstyle ':weather:europe:germany:* preferred-precipitation none zstyle ':weather:europe:germany:*:munich' preferred-precipitation snow
Then, the fictional `weather' plugin might run under the hood a command such as
zstyle -s ":weather:${continent}:${country}:${county}:${city}" preferred-precipitation REPLY
in order to retrieve your preference into the scalar variable $REPLY.
Usage
The forms that operate on patterns are the following.
If the -L option is given, listing is done in the form of calls to zstyle. The optional first argument, metapattern, is a pattern which will be matched against the string supplied as pattern when the style was defined. Note: this means, for example, `zstyle -L ":completion:*"' will match any supplied pattern beginning `:completion:', not just ":completion:*": use ':completion:\*' to match that. The optional second argument limits the output to a specific style (not a pattern). -L is not compatible with any other options.
The other forms can be used to look up or test styles for a given context.
Return 0 if the style is set, 1 otherwise.
Return 0 if name is set to `yes', 1 otherwise.
Return 0 if the style is set, 1 otherwise.
The -T option tests the values of the style like -t, but it returns status zero (rather than 2) if the style is not defined for any matching pattern.
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. A colon in the left string can be escaped with a backslash. The resulting strings are stored in the 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 `--'. See also -F.
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.
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).
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.
In all cases, option-arguments must appear either immediately following the option in the same positional parameter or in the next one. Even an optional argument may appear in the next parameter, unless it begins with a `-'. There is no special handling of `=' as with GNU-style argument parsers; given the spec `-foo:', the positional parameter `--foo=bar' is parsed as `--foo' with an argument of `=bar'.
When the names of two options that take no arguments overlap, the longest one wins, so that parsing for the specs `-foo -foobar' (for example) is unambiguous. However, due to the aforementioned handling of option-arguments, ambiguities may arise when at least one overlapping spec takes an argument, as in `-foo: -foobar'. In that case, the last matching spec wins.
The options of zparseopts itself cannot be stacked because, for example, the stack `-DEK' is indistinguishable from a spec for the GNU-style long option `--DEK'. The options of zparseopts itself are:
Note that the appearance in the positional parameters of an option without its required argument always aborts parsing and returns an error as described above regardless of whether this option is used.
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.
The -M option can be used like this:
set -- -a -bx -c y -cz baz -cend zparseopts -A bar -M a=foo b+: c:=b
to have the effect of
foo=(-a) bar=(-a '' -b xyz)