Z-Shell Community/Typeset

Created Mon, 20 Mar 2023 01:39:43 +0000 Modified Wed, 20 Sep 2023 10:25:01 +0000
2948 Words


Set or display attributes and values for shell parameters. Except as noted below for control flags that change the behavior, a parameter is created for each name that does not already refer to one. When inside a function, a new parameter is created for every name (even those that already exist) and is unset again when the function completes. See Local Parameters in zshparam(1). The same rules apply to special shell parameters, which retain their special attributes when made local.

For each name=value assignment, the parameter name is set to value.

If the shell option TYPESET_SILENT is not set, for each remaining name that refers to a parameter that is already set, the name and value of the parameter are printed in the form of an assignment. Nothing is printed for newly-created parameters, or when any attribute flags listed below are given along with the name. Using + instead of minus to introduce an attribute turns it off.

If no name is present, the names and values of all parameters are printed. In this case the attribute flags restrict the display to only those parameters that have the specified attributes, and using + rather than - to introduce the flag suppresses printing of the values of parameters when there is no parameter name.

All forms of the command handle scalar assignment. Array assignment is possible if any of the reserved words declare, export, float, integer, local, readonly or typeset is matched when the line is parsed (N.B. not when it is executed). In this case the arguments are parsed as assignments, except that the += syntax and the GLOB_ASSIGN option are not supported, and scalar values after = are not split further into words, even if expanded (regardless of the setting of the KSH_TYPESET option; this option is obsolete).

typeset [ {+|-}AHUaghlmrtux ] [ {+|-}EFLRZip [ n ] ] [ + ] [ name[=value] ... ]
typeset -T [ {+|-}Uglrux ] [ {+|-}LRZp [ n ] ] [ + | SCALAR[=value] array[=(value ...)] [ sep ] ]
typeset -f [ {+|-}TUkmtuz ] [ + ] [ name ... ]

Examples of the differences between command and reserved word parsing:

  • Reserved word parsing
typeset svar=$(echo one word) avar=(several words)

The above creates a scalar parameter svar and an array parameter avar as if the assignments had been:

svar="one word"
avar=(several words)

On the other hand:

  • Normal builtin interface
builtin typeset svar=$(echo two words)

The builtin keyword causes the above to use the standard builtin interface to typeset in which argument parsing is performed in the same way as for other commands. This example creates a scalar svar containing the value two and another scalar parameter words with no value. An array value in this case would either cause an error or be treated as an obscure set of glob qualifiers.

Arbitrary arguments are allowed if they take the form of assignments after command line expansion; however, these only perform scalar assignment:

typeset $var

The above sets the scalar parameter svar to the value val. Parentheses around the value within var would not cause array assignment as they will be treated as ordinary characters when $var is substituted. Any non-trivial expansion in the name part of the assignment causes the argument to be treated in this fashion:

typeset {var1,var2,var3}=name

The above syntax is valid, and has the expected effect of setting the three parameters to the same value, but the command line is parsed as a set of three normal command line arguments to typeset after expansion. Hence it is not possible to assign to multiple arrays by this means.

Note: that each interface to any of the commands my be disabled separately. For example, disable -r typeset disables the reserved word interface to typeset, exposing the builtin interface, while disable typeset disables the builtin.

Note: that disabling the reserved word interface for typeset may cause problems with the output of typeset -p , which assumes the reserved word interface is available in order to restore array and associative array values.

Unlike parameter assignment statements, typeset’s exit status on an assignment that involves a command substitution does not reflect the exit status of the command substitution. Therefore, to test for an error in a command substitution, separate the declaration of the parameter from its initialization:

typeset var1=$(exit 1) || echo "Trouble with var1"
typeset var1 && var1=$(exit 1) || echo "Trouble with var1"

To initialize a parameter param to a command output and mark it readonly, use typeset -r param or readonly param after the parameter assignment statement.

If no attribute flags are given, and either no name arguments are present or the flag +m is used, then each parameter name printed is preceded by a list of the attributes of that parameter (array, association, exported, float, integer, readonly, or undefined for autoloaded parameters not yet loaded). If +m is used with attribute flags, and all those flags are introduced with +, the matching parameter names are printed but their values are not.

The following control flags change the behavior of typeset:


If + appears by itself in a separate word as the last option, then the names of all parameters (functions with -f) are printed, but the values (function bodies) are not. No name arguments may appear, and it is an error for any other options to follow +.

The effect of + is as if all attribute flags which precede it were given with a + prefix. For example, typeset -U + is equivalent to typeset +U and displays the names of all arrays having the uniqueness attribute, whereas typeset -f -U + displays the names of all autoloadable functions. If + is the only option, then type information (array, readonly, etc.) is also printed for each parameter, in the same manner as typeset +m “*".


The -g (global) means that any resulting parameter will not be restricted to local scope.

Note: that this does not necessarily mean that the parameter will be global, as the flag will apply to any existing parameter (even if unset) from an enclosing function. This flag does not affect the parameter after creation, hence it has no effect when listing existing parameters, nor does the flag +g have any effect except in combination with -m (see below).


If the -m flag is given the name arguments are taken as patterns (use quoting to prevent these from being interpreted as file patterns). With no attribute flags, all parameters (or functions with the -f flag) with matching names are printed (the shell option TYPESET_SILENT is not used in this case).

If the +g flag is combined with -m, a new local parameter is created for every matching parameter that is not already local. Otherwise -m applies all other flags or assignments to the existing parameters.

Except when assignments are made with name=value, using +m forces the matching parameters and their attributes to be printed, even inside a function.

Note: that -m is ignored if no patterns are given, so typeset -m displays attributes but typeset -a +m does not.

-p [ n ]

If the -p option is given, parameters and values are printed in the form of a typeset command with an assignment, regardless of other flags and options.

Note: that the -h flag on parameters is respected; no value will be shown for these parameters.

-p may be followed by an optional integer argument. Currently only the value 1 is supported. In this case arrays and associative arrays are printed with newlines between indented elements for readability.

-T [ scalar[=value] array[=(value …)] [ sep ] ]

This flag has a different meaning when used with -f; see below.

Otherwise the -T option requires zero, two, or three arguments to be present. With no arguments, the list of parameters created in this fashion is shown. With two or three arguments, the first two are the name of a scalar and of an array parameter (in that order) that will be tied together in the manner of $PATH and $path. The optional third argument is a single-character separator which will be used to join the elements of the array to form the scalar; if absent, a colon is used, as with $PATH. Only the first character of the separator is significant; any remaining characters are ignored. Multibyte characters are not yet supported.

Only one of the scalar and array parameters may be assigned an initial value (the restrictions on assignment forms described above also apply).

Both the scalar and the array may be manipulated as normal. If one is unset, the other will automatically be unset too. There is no way of untying the variables without unsetting them, nor of converting the type of one of them with another typeset command; +T does not work, assigning an array to scalar is an error, and assigning a scalar to array sets it to be a single-element array.

Note: that both typeset -xT … and export -T … work, but only the scalar will be marked for export. Setting the value using the scalar version causes a split on all separators (which cannot be quoted). It is possi ble to apply -T to two previously tied variables but with a different separator character, in which case the vari ables remain joined as before but the separator is changed.

When an existing scalar is tied to a new array, the value of the scalar is preserved but no attribute other than export will be preserved.

Attribute flags that transform the final value (-L, -R, -Z, -l, -u) are only applied to the expanded value at the point of a parameter expansion expression using $. They are not applied when a parameter is retrieved internally by the shell for any purpose.

The following attribute flags may be specified:


The names refer to associative array parameters; see Array Parameters in zshparam(1).

-L [ n ]

Left justify and remove leading blanks from the value when the parameter is expanded. If n is nonzero, it defines the width of the field. If n is zero, the width is determined by the width of the value of the first assignment. In the case of numeric parameters, the length of the complete value assigned to the parameter is used to determine the width, not the value that would be output.

The width is the count of characters, which may be multibyte characters if the MULTIBYTE option is in effect.

Note: that the screen width of the character is not taken into account; if this is required, use padding with parameter expansion flags ${(ml…)…} as described in Parameter Expansion Flags in zshexpn(1).

When the parameter is expanded, it is filled on the right with blanks or truncated if necessary to fit the field.

Note: truncation can lead to unexpected results with numeric parameters. Leading zeros are removed if the -Z flag is also set.

-R [ n ]

Similar to -L, except that right justification is used; when the parameter is expanded, the field is left filled with blanks or truncated from the end. May not be combined with the -Z flag.


For arrays (but not for associative arrays), keep only the first occurrence of each duplicated value. This may also be set for tied parameters (see -T) or colon-separated special parameters like PATH or FIGNORE, etc.

Note: the flag takes effect on assignment, and the type of the variable being assigned to is determinative; for variables with shared values it is therefore recommended to set the flag for all interfaces, e.g. typeset -U PATH path.

This flag has a different meaning when used with -f; see below.

-Z [ n ]

Specially handled if set along with the -L flag. Otherwise, similar to -R, except that leading zeros are used for padding instead of blanks if the first non-blank character is a digit. Numeric parameters are specially handled: they are always eligible for padding with zeroes, and the zeroes are inserted at an appropriate place in the output.


The names refer to array parameters. An array parameter may be created this way, but it may be assigned to in the typeset statement only if the reserved word form of typeset is enabled (as it is by default). When displaying, both normal and associative arrays are shown.


The names refer to functions rather than parameters. No assignments can be made, and the only other valid flags are -t, -T, -k, -u, -U and -z. The flag -t turns on execution tracing for this function; the flag -T does the same, but turns off tracing for any named (not anonymous) function called from the present one, unless that function also has the -t or -T flag. The -u and -U flags cause the function to be marked for autoloading; -U also causes alias expansion to be suppressed when the function is loaded. See the description of the autoload builtin for details.

Note: that the builtin functions provides the same basic capabilities as typeset -f but gives access to a few extra options; autoload gives further additional options for the case typeset -fu and typeset -fU.


Hide: only useful for special parameters (those marked in the table in zshparam(1)), and for local parameters with the same name as a special parameter, though harmless for others. A special parameter with this attribute will not retain its special effect when made local. Thus after typeset -h PATH, a function containing typeset PATH will create an ordinary local parameter without the usual behaviour of PATH. Alternatively, the local parameter may itself be given this attribute; hence inside a function typeset -h PATH creates an ordinary local parameter and the special PATH parameter is not altered in any way.

It is also possible to create a local parameter using typeset +h special, where the local copy of special will retain its special properties regardless of having the -h attribute. Global special parameters loaded from shell modules (currently those in zsh/mapfile and zsh/parameter) are automatically given the -h attribute to avoid name clashes.


Hide value: specifies that typeset will not display the value of the parameter when listing parameters; the display for such parameters is always as if the + flag had been given. Use of the parameter is in other respects normal, and the option does not apply if the parameter is specified by name, or by pattern with the -m option. This is on by default for the parameters in the zsh/parameter and zsh/mapfile modules.

Note: that unlike the -h flag this is also useful for non-special parameters.

-i [ n ]

Use an internal integer representation. If n is nonzero it defines the output arithmetic base, otherwise it is determined by the first assignment. Bases from 2 to 36 inclusive are allowed.

-E [ n ]

Use an internal double-precision floating point representation. On output the variable will be converted to scientific notation. If n is nonzero it defines the number of significant figures to display; the default is ten.

-F [ n ]

Use an internal double-precision floating point representation. On output the variable will be converted to fixed-point decimal notation. If n is nonzero it defines the number of digits to display after the decimal point; the default is ten.


Convert the result to lower case whenever the parameter is expanded. The value is not converted when assigned.


The given names are marked readonly.

Note: that if name is a special parameter, the readonly attribute can be turned on, but cannot then be turned off.

If the POSIX_BUILTINS option is set, the readonly attribute is more restrictive: unset variables can be marked readonly and cannot then be set; furthermore, the readonly attribute cannot be removed from any variable.

It is still possible to change other attributes of the variable though, some of which like -U or -Z would affect the value. More generally, the readonly attribute should not be relied on as a security mechanism.

Note: that in zsh (like in pdksh but unlike most other shells) it is still possible to create a local variable of the same name as this is considered a different variable (though this variable, too, can be marked readonly). Special variables that have been made readonly retain their value and readonly attribute when made local.


Tags the named parameters. Tags have no special meaning to the shell. This flag has a different meaning when used with -f; see above.


Convert the result to upper case whenever the parameter is expanded. The value is not converted when assigned. This flag has a different meaning when used with -f; see above.


Mark for automatic export to the environment of subsequently executed commands. If the option GLOBAL_EXPORT is set, this implies the option -g, unless +g is also explicitly given; in other words the parameter is not made local to the enclosing function. This is for compatibility with previous versions of zsh.


Same as typeset.

float [ {+|-}Hghlprtux ] [ {+|-}EFLRZ [ n ] ] [ name[=value] … ]

Equivalent to typeset -E, except that options irrelevant to floating point numbers are not permitted.

integer [ {+|-}Hghlprtux ] [ {+|-}LRZi [ n ] ] [ name[=value] … ]

Equivalent to typeset -i, except that options irrelevant to integers are not permitted.

local [ {+|-}AHUahlprtux ] [ {+|-}EFLRZi [ n ] ] [ name[=value] … ]

Same as typeset, except that the options -g, and -f are not permitted. In this case the -x option does not force the use of -g, i.e. exported variables will be local to functions.


Same as typeset -r. With the POSIX_BUILTINS option set, same as typeset -gr.