MODULEFILE(4) | Modules | MODULEFILE(4) |
NAME¶
modulefile - files containing Tcl code for the Modules package
DESCRIPTION¶
modulefiles are written in the Tool Command Language, Tcl(n) and are interpreted by the modulecmd.tcl program via the module(1) user interface. modulefiles can be loaded, unloaded, or switched on-the-fly while the user is working; and can be used to implement site policies regarding the access and use of applications.
A modulefile begins with the magic cookie, #%Module. A version number may be placed after this string. The version number is useful as the modulefile format may change thus it reflects the minimum version of modulecmd.tcl required to interpret the modulefile. If a version number doesn't exist, then modulecmd.tcl will assume the modulefile is compatible. Files without the magic cookie or with a version number greater than the current version of modulecmd.tcl will not be interpreted.
Each modulefile contains the changes to a user's environment needed to access an application. Tcl is a simple programming language which permits modulefiles to be arbitrarily complex, depending upon the application's and the modulefile writer's needs. If support for extended tcl (tclX) has been configured for your installation of the Modules package, you may use all the extended commands provided by tclX, too.
A typical modulefile is a simple bit of code that set or add entries to the PATH, MANPATH, or other environment variables. A Modulefile is evaluated against current modulecmd.tcl's mode which leads to specific evaluation results. For instance if the modulefile sets a value to an environment variable, this variable is set when modulefile is loaded and unset when modulefile is unloaded.
Tcl has conditional statements that are evaluated when the modulefile is interpreted. This is very effective for managing path or environment changes due to different OS releases or architectures. The user environment information is encapsulated into a single modulefile kept in a central location. The same modulefile is used by every user on any machine. So, from the user's perspective, starting an application is exactly the same irrespective of the machine or platform they are on.
modulefiles also hide the notion of different types of shells. From the user's perspective, changing the environment for one shell looks exactly the same as changing the environment for another shell. This is useful for new or novice users and eliminates the need for statements such as "if you're using the C Shell do this ..., otherwise if you're using the Bourne shell do this ...". Announcing and accessing new software is uniform and independent of the user's shell. From the modulefile writer's perspective, this means one set of information will take care of every type of shell.
MODULES SPECIFIC TCL COMMANDS¶
The Modules Package uses commands which are extensions to the "standard" Tool Command Language Tcl(n) package. Unless otherwise specified, the Module commands return the empty string. Some commands behave differently when a modulefile is loaded or unloaded. The command descriptions assume the modulefile is being loaded.
- append-path [-d C|--delim C|--delim=C] [--duplicates] variable value...
- See prepend-path.
- break
- This is not a Modules-specific command, it's actually part of Tcl, which
has been overloaded similar to the continue and exit
commands to have the effect of causing the module not to be listed as
loaded and not affect other modules being loaded concurrently. All
non-environment commands within the module will be performed up to this
point and processing will continue on to the next module on the command
line. The break command will only have this effect if not used
within a Tcl loop though.
An example: Suppose that a full selection of modulefiles are needed for various different architectures, but some of the modulefiles are not needed and the user should be alerted. Having the unnecessary modulefile be a link to the following notavail modulefile will perform the task as required.
#%Module1.0 ## notavail modulefile ## proc ModulesHelp { } {
puts stderr "This module does nothing but alert the user"
puts stderr "that the [module-info name] module is not available" } module-whatis "Notifies user that module is not available." set curMod [module-info name] if { [ module-info mode load ] } {
puts stderr "Note: '$curMod' is not available for [uname sysname]." } break
- chdir directory
- Set the current working directory to directory.
- conflict modulefile...
- prereq and conflict control whether or not the
modulefile will be loaded. The prereq command lists
modulefiles which must have been previously loaded before the
current modulefile will be loaded. Similarly, the conflict
command lists modulefiles which conflict with the current
modulefile. If a list contains more than one modulefile,
then each member of the list acts as a Boolean OR operation. Multiple
prereq and conflict commands may be used to create a Boolean
AND operation. If one of the requirements have not been satisfied, an
error is reported and the current modulefile makes no changes to
the user's environment.
If an argument for prereq is a directory and any modulefile from the directory has been loaded, then the prerequisite is met. For example, specifying X11 as a prereq means that any version of X11, X11/R4 or X11/R5, must be loaded before proceeding.
If an argument for conflict is a directory and any other modulefile from that directory has been loaded, then a conflict will occur. For example, specifying X11 as a conflict will stop X11/R4 and X11/R5 from being loaded at the same time.
The parameter modulefile may also be a symbolic modulefile name or a modulefile alias. It may also leverage a specific syntax to finely select module version (see Advanced module version specifiers section below).
- continue
- This is not a modules specific command but another overloaded Tcl command and is similar to the break or exit commands except the module will be listed as loaded as well as performing any environment or Tcl commands up to this point and then continuing on to the next module on the command line. The continue command will only have this effect if not used within a Tcl loop though.
- exit [N]
- This is not a modules specific command but another overloaded Tcl command and is similar to the break or continue commands. However, this command will cause the immediate cessation of this module and any additional ones on the command line. This module and the subsequent modules will not be listed as loaded. No environment commands will be performed in the current module.
- getenv variable [value]
- Returns value of environment variable. If variable is not defined, value is returned if set, _UNDEFINED_ is returned otherwise. The getenv command should be preferred over the Tcl global variable env to query environment variables.
- is-avail modulefile...
- The is-avail command returns a true value if any of the listed
modulefiles exists in enabled MODULEPATH. If a list contains
more than one modulefile, then each member acts as a boolean OR
operation. If an argument for is-avail is a directory and a
modulefile exists in the directory is-avail would return a
true value.
The parameter modulefile may also be a symbolic modulefile name or a modulefile alias. It may also leverage a specific syntax to finely select module version (see Advanced module version specifiers section below).
- is-loaded [modulefile...]
- The is-loaded command returns a true value if any of the listed
modulefiles has been loaded or if any modulefile is loaded
in case no argument is provided. If a list contains more than one
modulefile, then each member acts as a boolean OR operation. If an
argument for is-loaded is a directory and any modulefile
from the directory has been loaded is-loaded would return a true
value.
The parameter modulefile may also be a symbolic modulefile name or a modulefile alias. It may also leverage a specific syntax to finely select module version (see Advanced module version specifiers section below).
- is-saved [collection...]
- The is-saved command returns a true value if any of the listed
collections exists or if any collection exists in case no
argument is provided. If a list contains more than one collection,
then each member acts as a boolean OR operation.
If MODULES_COLLECTION_TARGET is set, a suffix equivalent to the value of this variable is appended to the passed collection name. In case no collection argument is provided, a true value will only be returned if a collection matching currently set target exists.
- is-used [directory...]
- The is-used command returns a true value if any of the listed directories has been enabled in MODULEPATH or if any directory is enabled in case no argument is provided. If a list contains more than one directory, then each member acts as a boolean OR operation.
- module [sub-command] [sub-command-args]
- Contains the same sub-commands as described in the module(1) man
page in the Module Sub-Commands section. This command permits a
modulefile to load or unload other
modulefiles. No checks are made to ensure that the
modulefile does not try to load itself. Often it is useful to have
a single modulefile that performs a number of module load
commands. For example, if every user on the system requires a basic set of
applications loaded, then a core modulefile would contain the
necessary module load commands.
Command line switches --auto, --no-auto and --force are ignored when passed to a module command set in a modulefile.
- module-alias name modulefile
- Assigns the modulefile to the alias name. This command
should be placed in one of the modulecmd.tcl rc files in order to
provide shorthand invocations of frequently used modulefile names.
The parameter modulefile may be either
- a fully qualified modulefile with name and version
- a symbolic modulefile name
- another modulefile alias
- module-info option [info-args]
- Provide information about the modulecmd.tcl program's state. Some
of the information is specific to the internals of modulecmd.tcl.
option is the type of information to be provided, and
info-args are any arguments needed.
module-info alias name
module-info command [commandname]
Returns 1 if modulecmd.tcl's command is commandname. commandname can be: load, unload, reload, source, switch, display, avail, aliases, list, whatis, search, purge, restore, help or test.
module-info loaded modulefile
module-info mode [modetype]
Returns 1 if modulecmd.tcl's mode is modetype. modetype can be: load, unload, remove, switch, display, help, test or whatis.
module-info name
module-info shell [shellname]
If a shellname is given, returns 1 if modulecmd.tcl's current shell is shellname, returns 0 otherwise. shellname can be: sh, bash, ksh, zsh, csh, tcsh, fish, tcl, perl, python, ruby, lisp, cmake, r.
module-info shelltype [shelltypename]
If a shelltypename is given, returns 1 if modulecmd.tcl's current shell type is shelltypename, returns 0 otherwise. shelltypename can be: sh, csh, fish, tcl, perl, python, ruby, lisp, cmake, r.
module-info specified
module-info symbols modulefile
module-info type
module-info version modulefile
- module-version modulefile version-name...
- Assigns the symbolic version-name to the modulefile. This
command should be placed in one of the modulecmd.tcl rc files in
order to provide shorthand invocations of frequently used
modulefile names.
The special version-name default specifies the default version to be used for module commands, if no specific version is given. This replaces the definitions made in the .version file in former modulecmd.tcl releases.
The parameter modulefile may be either
- a fully or partially qualified modulefile with name / version. If name is . (dot) then the current directory name is assumed to be the module name. (Use this for deep modulefile directories.)
- a symbolic modulefile name
- another modulefile alias
- module-virtual name modulefile
- Assigns the modulefile to the virtual module name. This
command should be placed in rc files in order to define virtual modules.
A virtual module stands for a module name associated to a modulefile. The modulefile is the script interpreted when loading or unloading the virtual module which appears or can be found with its virtual name.
The parameter modulefile corresponds to the relative or absolute file location of a modulefile.
- module-whatis string
- Defines a string which is displayed in case of the invocation of the
module whatis command. There may be more than one
module-whatis line in a modulefile. This command takes no
actions in case of load, display, etc. invocations of
modulecmd.tcl.
The string parameter has to be enclosed in double-quotes if there's more than one word specified. Words are defined to be separated by whitespace characters (space, tab, cr).
- prepend-path [-d C|--delim C|--delim=C] [--duplicates] variable value...
- Append or prepend value to environment variable. The
variable is a colon, or delimiter, separated list such as
PATH=directory:directory:directory. The default delimiter is a
colon :, but an arbitrary one can be given by the --delim
option. For example a space can be used instead (which will need to be
handled in the Tcl specially by enclosing it in " " or
{ }). A space, however, can not be specified by the
--delim=C form.
A reference counter environment variable is also set to increase the number of times value has been added to environment variable. This reference counter environment variable is named by suffixing variable by _modshare.
When value is already defined in environement variable, it is not added again except if --duplicates option is set.
If the variable is not set, it is created. When a modulefile is unloaded, append-path and prepend-path become remove-path.
If value corresponds to the concatenation of multiple elements separated by colon, or delimiter, character, each element is treated separately.
- prereq modulefile...
- See conflict.
- remove-path [-d C|--delim C|--delim=C] [--index] variable value...
- Remove value from the colon, or delimiter, separated list in
variable. See prepend-path or append-path for further
explanation of using an arbitrary delimiter. Every string between colons,
or delimiters, in variable is compared to value. If the two
match, value is removed from variable if its reference
counter is equal to 1 or unknown.
When --index option is set, value refers to an index in variable list. The string element pointed by this index is set for removal.
Reference counter of value in variable denotes the number of times value has been added to variable. This information is stored in environment variable_modshare. When attempting to remove value from variable, relative reference counter is checked and value is removed only if counter is equal to 1 or not defined. Otherwise value is kept in variable and reference counter is decreased by 1.
If value corresponds to the concatenation of multiple elements separated by colon, or delimiter, character, each element is treated separately.
- set-alias alias-name alias-string
- Sets an alias or function with the name alias-name in the user's environment to the string alias-string. For some shells, aliases are not possible and the command has no effect. When a modulefile is unloaded, set-alias becomes unset-alias.
- set-function function-name function-string
- Creates a function with the name function-name in the user's environment with the function body function-string. For some shells, functions are not possible and the command has no effect. When a modulefile is unloaded, set-function becomes unset-function.
- setenv variable value
- Set environment variable to value. The setenv command will also change the process' environment. A reference using Tcl's env associative array will reference changes made with the setenv command. Changes made using Tcl's env associative array will NOT change the user's environment variable like the setenv command. An environment change made this way will only affect the module parsing process. The setenv command is also useful for changing the environment prior to the exec or system command. When a modulefile is unloaded, setenv becomes unsetenv. If the environment variable had been defined it will be overwritten while loading the modulefile. A subsequent unload will unset the environment variable - the previous value cannot be restored! (Unless you handle it explicitly ... see below.)
- system string
- Run string command through shell. On Unix, command is passed to the /bin/sh shell whereas on Windows it is passed to cmd.exe. modulecmd.tcl redirects stdout to stderr since stdout would be parsed by the evaluating shell. The exit status of the executed command is returned.
- uname field
- Provide lookup of system information. Most field information are
retrieved from the tcl_platform array (see the tclvars(n)
man page). Uname will return the string unknown if information is
unavailable for the field.
uname will invoke the uname(1) command in order to get the operating system version and domainname(1) to figure out the name of the domain.
field values are:
- sysname: the operating system name
- nodename: the hostname
- domain: the name of the domain
- release: the operating system release
- version: the operating system version
- machine: a standard name that identifies the system's hardware
- unset-alias alias-name
- Unsets an alias with the name alias-name in the user's environment.
- unset-function function-name
- Removes a function with the name function-name from the user's environment.
- unsetenv variable [value]
- Unsets environment variable. However, if there is an optional value, then when unloading a module, it will set variable to value. The unsetenv command changes the process' environment like setenv.
- x-resource [resource-string|filename]
- Merge resources into the X11 resource database. The resources are used to
control look and behavior of X11 applications. The command will attempt to
read resources from filename. If the argument isn't a valid file
name, then string will be interpreted as a resource. Either
filename or resource-string is then passed down to be
xrdb(1) command.
modulefiles that use this command, should in most cases contain one or more x-resource lines, each defining one X11 resource. The DISPLAY environment variable should be properly set and the X11 server should be accessible. If x-resource can't manipulate the X11 resource database, the modulefile will exit with an error message.
Examples:
x-resource /u2/staff/leif/.xres/Ileaf
x-resource [glob ~/.xres/ileaf]
x-resource {Ileaf.popup.saveUnder: True}
MODULES VARIABLES¶
The ModulesCurrentModulefile variable contains the full pathname of the modulefile being interpreted.
LOCATING MODULEFILES¶
Every directory in MODULEPATH is searched to find the modulefile. A directory in MODULEPATH can have an arbitrary number of sub-directories. If the user names a modulefile to be loaded which is actually a directory, the directory is opened and a search begins for an actual modulefile. First, modulecmd.tcl looks for a file with the name .modulerc in the directory. If this file exists, its contents will be evaluated as if it was a modulefile to be loaded. You may place module-version, module-alias and module-virtual commands inside this file.
Additionally, before seeking for .modulerc files in the module directory, the global modulerc file and the .modulerc file found at the root of the modulepath directory are sourced, too. If a named version default now exists for the modulefile to be loaded, the assigned modulefile now will be sourced. Otherwise the file .version is looked up in the module directory.
If the .version file exists, it is opened and interpreted as Tcl code and takes precedence over a .modulerc file in the same directory. If the Tcl variable ModulesVersion is set by the .version file, modulecmd.tcl will use the name as if it specifies a modulefile in this directory. This will become the default modulefile in this case. ModulesVersion cannot refer to a modulefile located in a different directory.
If ModulesVersion is a directory, the search begins anew down that directory. If the name does not match any files located in the current directory, the search continues through the remaining directories in MODULEPATH.
Every .version and .modulerc file found is interpreted as Tcl code. The difference is that .version only applies to the current directory, and the .modulerc applies to the current directory and all subdirectories. Changes made in these files will affect the subsequently interpreted modulefile.
If no default version may be figured out, an implicit default is selected when this behavior is enabled (see MODULES_IMPLICIT_DEFAULT in module(1)). If disabled, module names should be fully qualified when no explicit default is defined for them, otherwise no default version is found and an error is returned. If enabled, then the highest numerically sorted modulefile, virtual module or module alias under the directory will be used. The dictionary comparison method of the lsort(n) Tcl command is used to achieve this sort. If highest numerically sorted element is an alias, search continues on its modulefile target.
For example, it is possible for a user to have a directory named X11 which simply contains a .version file specifying which version of X11 is to be loaded. Such a file would look like:
#%Module1.0 ## ## The desired version of X11 ## set ModulesVersion "R4"
The equivalent .modulerc would look like:
#%Module1.0 ## ## The desired version of X11 ## module-version "./R4" default
If the extended default mechanism is enabled (see MODULES_EXTENDED_DEFAULT in module(1)) the module version specified is matched against starting portion of existing module versions, where portion is a substring separated from the rest of version string by a . character.
When the implicit default mechanism and the Advanced module version specifiers are both enabled, a default and latest symbolic versions are automatically defined for each module name (also at each directory level in case of deep modulefile). Unless a symbolic version, alias, or regular module version already exists for these version names.
If user names a modulefile that cannot be found in the first modulepath directory, modulefile will be searched in next modulepath directory and so on until a matching modulefile is found. If search goes through a module alias or a symbolic version, this alias or symbol is resolved by first looking at the modulefiles in the modulepath where this alias or symbol is defined. If not found, resolution looks at the other modulepaths in their definition order.
When locating modulefiles, if a .modulerc, a .version, a directory or a modulefile cannot be read during the search it is simply ignored with no error message produced. Visibility of modulefiles can thus be adapted to the rights the user has been granted. Exception is made when trying to directly access a directory or a modulefile. In this case, the access issue is returned as an error message.
A modulefile, virtual module, module alias or symbolic version whose name or element in their name starts with a . (dot) are considered hidden. Hidden modulefile, virtual module, module alias or symbolic version are not displayed or taken into account except if they are explicitly named. By inheritance, a symbolic version-name assigned to a hidden modulefile, virtual module or module alias is displayed or taken into account only if explicitly named. Non-hidden module alias targeting a hidden modulefile appears like any other non-hidden module alias. Finally, a hidden symbolic version targeting a non-hidden module will be displayed along its non-hidden target.
ADVANCED MODULE VERSION SPECIFIERS¶
When the advanced module version specifiers mechanism is enabled (see MODULES_ADVANCED_VERSION_SPEC in module(1)), the specification of modulefile passed on Modules specific Tcl commands changes. After the module name a version constraint prefixed by the @ character may be added. It could be directly appended to the module name or separated from it with a space character.
Constraints can be expressed to refine the selection of module version to:
- a single version with the @version syntax, for instance foo@1.2.3 syntax will select module foo/1.2.3
- a list of versions with the @version1,version2,... syntax, for instance foo@1.2.3,1.10 will match modules foo/1.2.3 and foo/1.10
- a range of versions with the @version1:, @:version2 and @version1:version2 syntaxes, for instance foo@1.2: will select all versions of module foo greater than or equal to 1.2, foo@:1.3 will select all versions less than or equal to 1.3 and foo@1.2:1.3 matches all versions between 1.2 and 1.3 including 1.2 and 1.3 versions
Advanced specification of single version or list of versions may benefit from the activation of the extended default mechanism (see MODULES_EXTENDED_DEFAULT in module(1)) to use an abbreviated notation like @1 to refer to more precise version numbers like 1.2.3. Range of versions on its side natively handles abbreviated versions.
In order to be specified in a range of versions or compared to a range of versions, the version major element should corresponds to a number. For instance 10a, 1.2.3, 1.foo are versions valid for range comparison whereas default or foo.2 versions are invalid for range comparison.
If the implicit default mechanism is also enabled (see MODULES_IMPLICIT_DEFAULT in module(1)), a default and latest symbolic versions are automatically defined for each module name (also at each directory level for deep modulefiles). These automatic version symbols are defined unless a symbolic version, alias, or regular module version already exists for these default or latest version names. Using the mod@latest (or mod/latest) syntax ensures highest available version will be selected.
MODULEFILE SPECIFIC HELP¶
Users can request help about a specific modulefile through the module(1) command. The modulefile can print helpful information or start help oriented programs by defining a ModulesHelp subroutine. The subroutine will be called when the module help modulefile command is used.
MODULEFILE SPECIFIC TEST¶
Users can request test of a specific modulefile through the module(1) command. The modulefile can perform some sanity checks on its definition or on its underlying programs by defining a ModulesTest subroutine. The subroutine will be called when the module test modulefile command is used. The subroutine should return 1 in case of success. If no or any other value is returned, test is considered failed.
MODULEFILE DISPLAY¶
The module display modulefile command will detail all changes that will be made to the environment. After displaying all of the environment changes modulecmd.tcl will call the ModulesDisplay subroutine. The ModulesDisplay subroutine is a good place to put additional descriptive information about the modulefile.
ENVIRONMENT¶
- MODULEPATH
- Path of directories containing modulefiles.
SEE ALSO¶
module(1), ml(1), Tcl(n), TclX(n), xrdb(1), exec(n), uname(1), domainname(1), tclvars(n), lsort(n)
NOTES¶
Tcl was developed by John Ousterhout at the University of California at Berkeley.
TclX was developed by Karl Lehenbauer and Mark Diekhans.
COPYRIGHT¶
1996-1999 John L. Furlani & Peter W. Osel, 1998-2017 R.K.Owen, 2002-2004 Mark Lakata, 2004-2017 Kent Mein, 2016-2020 Xavier Delaruelle
2020-07-30 | 4.5.2 |