module [switches] [sub-command [sub-command-args]]
module is a user interface to the Modules package. The Modules package provides for the dynamic modification of the user’s environment via modulefiles.
Each modulefile contains the information needed to configure the shell for an application. Once the Modules package is initialized, the environment can be modified on a per-module basis using the module command which interprets modulefiles. Typically modulefiles instruct the module command to alter or set shell environment variables such as PATH, MANPATH, etc. Modulefiles may be shared by many users on a system and users may have their own set to supplement or replace the shared modulefiles.
The modulefiles are added to and removed from the current environment by the user. The environment changes contained in a modulefile can be summarized through the module command as well. If no arguments are given, a summary of the module usage and sub-commands are shown.
The action for the module command to take is described by the sub-command and its associated arguments.
The Modules package and the module command are initialized when a shell-specific initialization script is sourced into the shell. The script creates the module command as either an alias or function and creates Modules environment variables.
The module alias or function executes the modulecmd.tcl program located in /usr/share/Modules/libexec and has the shell evaluate the command’s output. The first argument to modulecmd.tcl specifies the type of shell.
The initialization scripts are kept in /usr/share/Modules/init/<shell> where <shell> is the name of the sourcing shell. For example, a C Shell user sources the /usr/share/Modules/init/csh script. The sh, csh, tcsh, bash, ksh, zsh and fish shells are supported by modulecmd.tcl. In addition, python, perl, ruby, tcl, cmake, r and lisp “shells” are supported which writes the environment changes to stdout as python, perl, ruby, tcl, lisp, r or cmake code.
Initialization may also be performed by calling the autoinit sub-command of the modulecmd.tcl program. Evaluation into the shell of the result of this command defines the module alias or function.
Examples of initialization¶
C Shell initialization (and derivatives):
source /usr/share/Modules/init/csh module load modulefile modulefile ...
Bourne Shell (sh) (and derivatives):
. /usr/share/Modules/init/sh module load modulefile modulefile ...
require "/usr/share/Modules/init/perl.pm"; &module('load', 'modulefile', 'modulefile', '...');
import os exec(open('/usr/share/Modules/init/python.py').read()) module('load, 'modulefile', 'modulefile', '...')
Bourne Shell (sh) (and derivatives) with autoinit sub-command:
eval "`/usr/share/Modules/libexec/modulecmd.tcl sh autoinit`"
Upon invocation modulecmd.tcl sources if it exists a site-specific configuration script located in /usr/share/Modules/etc/siteconfig.tcl. This Tcl script enables to supersede any global variable or procedure definition of modulecmd.tcl.
Afterward, modulecmd.tcl sources rc files which contain global, user and modulefile specific setups. These files are interpreted as modulefiles. See modulefile for detailed information.
Upon invocation of modulecmd.tcl module run-command files are sourced in the following order:
- Global RC file as specified by $MODULERCFILE or /usr/share/Modules/etc/rc. If $MODULERCFILE points to a directory, the modulerc file in this directory is used as global RC file.
- User specific module RC file $HOME/.modulerc
- All .modulerc and .version files found during modulefile seeking.
Command line switches¶
The module command accepts command line switches as its first parameter. These may be used to control output format of all information displayed and the module behavior in case of locating and interpreting modulefiles.
All switches may be entered either in short or long notation. The following switches are accepted:
Give some helpful usage information, and terminates the command.
Lists the current version of the module command. The command then terminates without further processing.
Debug mode. Causes module to print debugging messages about its progress.
Pipe all message output into less (or if set, $MODULES_PAGER) if error output stream is a terminal. See also MODULES_PAGER section.
Do not pipe message output into a pager.
Display avail, list and savelist output in short format.
Display avail, list and savelist output in long format.
On avail sub-command, display only the default version of each module name. Default version is either the explicitly set default version or the highest numerically sorted modulefile if no default version set (see Locating Modulefiles section in the modulefile man page).
On avail sub-command, display only the highest numerically sorted version of each module name (see Locating Modulefiles section in the modulefile man page).
Print the usage of each sub-command. If an argument is given, print the Module-specific help information for the modulefile.
Load modulefile into the shell environment.
Remove modulefile from the shell environment.
swap [modulefile1] modulefile2
switch [modulefile1] modulefile2
Switch loaded modulefile1 with modulefile2. If modulefile1 is not specified, then it is assumed to be the currently loaded module with the same root name as modulefile2.
Display information about one or more modulefiles. The display sub-command will list the full path of the modulefile and the environment changes the modulefile will make if loaded. (Note: It will not display any environment changes found within conditional statements.)
List loaded modules.
avail [-d|-L] [-t|-l] [path…]
List all available modulefiles in the current MODULEPATH. All directories in the MODULEPATH are recursively searched for files containing the modulefile magic cookie. If an argument is given, then each directory in the MODULEPATH is searched for modulefiles whose pathname, symbolic version-name or alias match the argument. Argument may contain wildcard characters. Multiple versions of an application can be supported by creating a subdirectory for the application containing modulefiles for each version.
Symbolic version-names and aliases found in the search are displayed in the result of this sub-command. Symbolic version-names are displayed next to the modulefile they are assigned to within parenthesis. Aliases are listed in the MODULEPATH section where they have been defined. To distinguish aliases from modulefiles a @ symbol is added within parenthesis next to their name. Aliases defined through a global or user specific module RC file are listed under the global/user modulerc section.
List all available symbolic version-names and aliases in the current MODULEPATH. All directories in the MODULEPATH are recursively searched in the same manner than for the avail sub-command. Only the symbolic version-names and aliases found in the search are displayed.
use [-a|–append] directory…
Prepend one or more directories to the MODULEPATH environment variable. The –append flag will append the directory to MODULEPATH.
Reference counter environment variable MODULEPATH_modshare is also set to increase the number of times directory has been added to MODULEPATH.
Remove one or more directories from the MODULEPATH environment variable if reference counter of these directories is equal to 1 or unknown.
Reference counter of directory in MODULEPATH denotes the number of times directory has been enabled. When attempting to remove directory from MODULEPATH, reference counter variable MODULEPATH_modshare is checked and directory is removed only if its relative counter is equal to 1 or not defined. Elsewhere directory is kept and reference counter is decreased by 1.
Unload then load all loaded modulefiles.
Unload all loaded modulefiles.
Execute modulefile into the shell environment. modulefile must be specified with a fully qualified path. Once executed modulefile is not marked loaded in shell environment which differ from load sub-command.
Display the information set up by the module-whatis commands inside the specified modulefiles. These specified modulefiles may be expressed using wildcard characters. If no modulefile is specified, all module-whatis lines will be shown.
Seeks through the module-whatis informations of all modulefiles for the specified string. All module-whatis informations matching the string will be displayed. string may contain wildcard characters.
Execute and display results of the Module-specific tests for the modulefile.
Record the currently set MODULEPATH directory list and the currently loaded modulefiles in a collection file under the user’s collection directory $HOME/.module. If collection name is not specified, then it is assumed to be the default collection. If collection is a fully qualified path, it is saved at this location rather than under the user’s collection directory.
If MODULES_COLLECTION_TARGET is set, a suffix equivalent to the value of this variable will be appended to the collection file name.
By default, if loaded modulefile corresponds to the default module version, the bare module name is recorded. If MODULES_COLLECTION_PIN_VERSION is set to 1, module version is always recorded even if it is the default version.
Restore the environment state as defined in collection. If collection name is not specified, then it is assumed to be the default collection. If collection is a fully qualified path, it is restored from this location rather than from a file under the user’s collection directory. If MODULES_COLLECTION_TARGET is set, a suffix equivalent to the value of this variable is appended to the collection file name to restore.
When restoring a collection, the currently set MODULEPATH directory list and the currently loaded modulefiles are unused and unloaded then used and loaded to exactly match the MODULEPATH and loaded modulefiles lists saved in this collection file. The order of the paths and modulefiles set in collection is preserved when restoring. It means that currently loaded modules are unloaded to get the same LOADEDMODULES root than collection and currently used module paths are unused to get the same MODULEPATH root. Then missing module paths are used and missing modulefiles are loaded.
Delete the collection file under the user’s collection directory. If collection name is not specified, then it is assumed to be the default collection. If MODULES_COLLECTION_TARGET is set, a suffix equivalent to the value of this variable will be appended to the collection file name.
Display the content of collection. If collection name is not specified, then it is assumed to be the default collection. If collection is a fully qualified path, this location is displayed rather than a collection file under the user’s collection directory. If MODULES_COLLECTION_TARGET is set, a suffix equivalent to the value of this variable will be appended to the collection file name.
List collections that are currently saved under the user’s collection directory. If MODULES_COLLECTION_TARGET is set, only collections matching the target suffix will be displayed.
Add modulefile to the shell’s initialization file in the user’s home directory. The startup files checked (in order) are:
C Shell.modules, .cshrc, .csh_variables and .login
TENEX C Shell.modules, .tcshrc, .cshrc, .csh_variables and .login
Bourne and Korn Shells.modules, .profile
GNU Bourne Again Shell.modules, .bash_profile, .bash_login, .profile and .bashrc
Z Shell.modules, .zshrc, .zshenv and .zlogin
Friendly Interactive Shell.modules, .config/fish/config.fish
If a module load line is found in any of these files, the modulefiles are appended to any existing list of modulefiles. The module load line must be located in at least one of the files listed above for any of the init sub-commands to work properly. If the module load line is found in multiple shell initialization files, all of the lines are changed.
Does the same as initadd but prepends the given modules to the beginning of the list.
Remove modulefile from the shell’s initialization files.
initswitch modulefile1 modulefile2
Switch modulefile1 with modulefile2 in the shell’s initialization files.
List all of the modulefiles loaded from the shell’s initialization file.
Clear all of the modulefiles from the shell’s initialization files.
Print path to modulefile.
Print path of available modulefiles matching argument.
append-path [-d C|–delim C|–delim=C] [–duplicates] variable value…
Append value to environment variable. The variable is a colon, or delimiter, separated list. See append-path in the modulefile man page for further explanation.
prepend-path [-d C|–delim C|–delim=C] [–duplicates] variable value…
Prepend value to environment variable. The variable is a colon, or delimiter, separated list. See prepend-path in the modulefile man page for further explanation.
remove-path [-d C|–delim C|–delim=C] [–index] variable value…
Remove value from the colon, or delimiter, separated list in environment variable. See remove-path in the modulefile man page for further explanation.
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. Returns a false value elsewhere. See is-loaded in the modulefile man page for further explanation.
Returns a true value if any of the listed collections exists or if any collection exists in case no argument is provided. Returns a false value elsewhere. See is-saved in the modulefile man page for further explanation.
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. Returns a false value elsewhere. See is-used in the modulefile man page for further explanation.
Returns a true value if any of the listed modulefiles exists in enabled MODULEPATH. Returns a false value elsewhere. See is-avail in the modulefile man page for further explanation.
Returns the names of currently loaded modules matching passed modulefile. Returns an empty string if passed modulefile does not match any loaded modules. See module-info loaded in the modulefile man page for further explanation.
modulefiles are written in the Tool Command Language (Tcl) and are interpreted by modulecmd.tcl. modulefiles can use conditional statements. Thus the effect a modulefile will have on the environment may change depending upon the current state of the environment.
Environment variables are unset when unloading a modulefile. Thus, it is possible to load a modulefile and then unload it without having the environment variables return to their prior state.
Collections describe a sequence of module use then module load commands that are interpreted by modulecmd.tcl to set the user environment as described by this sequence. When a collection is activated, with the restore sub-command, module paths and loaded modules are unused or unloaded if they are not part or if they are not ordered the same way as in the collection.
Collections are generated by the save sub-command that dumps the current user environment state in terms of module paths and loaded modules. By default collections are saved under the $HOME/.module directory.
Collections may be valid for a given target if they are suffixed. In this case these collections can only be restored if their suffix correspond to the current value of the MODULES_COLLECTION_TARGET environment variable (see the dedicated section of this topic below).
The module command exits with 0 if its execution succeed. Elsewhere 1 is returned.
A colon separated list of all loaded modulefiles.
The path that the module command searches when looking for modulefiles. Typically, it is set to the master modulefiles directory, /usr/share/Modules/modulefiles, by the initialization script. MODULEPATH can be set using module use or by the module initialization script to search group or personal modulefile directories before or after the master modulefile directory.
Path elements registered in the MODULEPATH environment variable may contain reference to environment variables which are converted to their corresponding value by module command each time it looks at the MODULEPATH value. If an environment variable referred in a path element is not defined, its reference is converted to an empty string.
The location of the master Modules package file directory containing module command initialization scripts, the executable program modulecmd.tcl, and a directory containing a collection of master modulefiles.
The location of the active module command script.
If set to 1, register exact version number of modulefiles when saving a collection. Elsewhere modulefile version number is omitted if it corresponds to the implicit or explicitly set default version.
The collection target that determines what collections are valid thus reachable on the current system.
Collection directory may sometimes be shared on multiple machines which may use different modules setup. For instance modules users may access with the same HOME directory multiple systems using different OS versions. When it happens a collection made on machine 1 may be erroneous on machine 2.
When a target is set, only the collections made for that target are available to the restore, savelist, saveshow and saverm sub-commands. Saving collection registers the target footprint by suffixing the collection filename with
.$MODULES_COLLECTION_TARGET. Collection target is not involved when collection is specified as file path on the saveshow, restore and save sub-commands.
For example, the MODULES_COLLECTION_TARGET variable may be set with results from commands like lsb_release, hostname, dnsdomainname, etc.
Text viewer for use to paginate message output if error output stream is attached to a terminal. The value of this variable is composed of a pager command name or path eventually followed by command-line options.
Paging command and options are defined for Modules in the following order of preference: MODULES_PAGER environment variable, then the default set in modulecmd.tcl script configuration. Which means MODULES_PAGER overrides default configuration.
If MODULES_PAGER variable is set to an empty string or to the value cat, pager will not be launched.
Value to set to environment variable <VAR> for modulecmd.tcl run-time execution if <VAR> is referred in MODULES_RUN_QUARANTINE.
A space separated list of environment variable names that should be passed indirectly to modulecmd.tcl to protect its run-time environment from side-effect coming from their current definition.
Each variable found in MODULES_RUN_QUARANTINE will have its value emptied or set to the value of the corresponding MODULES_RUNENV_<VAR> variable when defining modulecmd.tcl run-time environment.
Original values of these environment variables set in quarantine are passed to modulecmd.tcl via <VAR>_modquar variables.
If set to 1, disable any xtrace or verbose debugging property set on current shell session for the duration of either the module command or the module shell initialization script. Only applies to Bourne Shell (sh) and its derivatives.
If set to 1 prior to Modules package initialization, enable Modules compatibility version (3.2 release branch) rather main version at initialization scripts running time. Modules package compatibility version should be installed along with main version for this environment variable to have any effect.
A colon separated list of the full pathname for all loaded modulefiles.
Value of environment variable <VAR> passed to modulecmd.tcl in order to restore <VAR> to this value once started.
Reference counter variable for path-like variable <VAR>. A colon separated list containing pairs of elements. A pair is formed by a path element followed its usage counter which represents the number of times this path has been enabled in variable <VAR>. A colon separates the two parts of the pair.
The MODULESHOME directory.
The system-wide modules rc file. The location of this file can be changed using the MODULERCFILE environment variable as described above.
The user specific modules rc file.
The user specific collection directory.
The directory for system-wide modulefiles. The location of the directory can be changed using the MODULEPATH environment variable as described above.
The modulefile interpreter that gets executed upon each invocation of module.
The Modules package initialization file sourced into the user’s environment.