modules/doc/module.1.in

.TH MODULE 1 "10 October 2005
.nh
.SH NAME
module \- command interface to the Modules package
.SH SYNOPSIS
.B module
[
.I switches
]
[
.I sub-command
]
.I [ sub-command-args ]
.SH DESCRIPTION
.LP
.B module
is a user interface to the Modules package.
The Modules package provides for the dynamic modification of the user's
environment via
.I modulefiles.
.LP
Each
.I 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 
.B module
command which interprets
.I modulefiles.
Typically
.I modulefiles
instruct the
.B module
command to alter or set shell environment variables such as PATH, MANPATH,
etc.
.I modulefiles
may be shared by many users on a system and users may have their own
collection to supplement or replace the shared
.I modulefiles.
.LP
The
.I modulefiles
are added to and removed from the current
environment by the user.
The environment changes contained in a
.I modulefile
can be summarized through the
.B module
command as well.
If no arguments are given, a summary of the
.B module
usage and
.I sub-commands
are shown.
.LP
The action for the
.B module
command to take is described by the
.I sub-command
and its associated arguments.
.SS Package Initialization
.LP
The Modules package and the
.B module
command are initialized when a shell-specific initialization script is
sourced into the shell.
The script creates the
.B module
command, either as an alias or shell function,
creates Modules environment variables,
and if enabled to do so, a snapshow of the environment is saved as either
(if BEGINENV=1)
.I $HOME/.modulesbeginenv
or (if BEGINENV=99) whatever
.I $MODULESBEGINENV
points to.

The
.B module
alias or function executes the
.B modulecmd
program and has the shell evaluate
the command's output.  The first argument to
.B modulecmd
specifies the type of shell.
.LP
The initialization scripts are kept in
.I $MODULESHOME/init/<shell>
where
.I <shell>
is the name of the sourcing shell.
The sh, csh, tcsh, bash, ksh, and zsh shells are supported by
.B modulecmd.
In addition, python and perl "shells" are supported, which writes
the environment changes to stdout as python or perl code.

.SS Modulecmd startup
.LP
Upon invocation \fImodulecmd\fP sources rc files which contain global, user
and modulefile specific setups. These files are interpreted as modulefiles.
See \fBmodulefile(4)\fP for detailed information.
.LP
Upon invocation of modulecmd module RC files are sourced in the following
order:
.nf
	
	Global RC file as specified by ${\s-1MODULERCFILE\s0} or 
	    ${\s-1MODULESHOME\s0}/etc/rc

	User specific module RC file ${\s-1HOME\s0}/.modulerc

	All .modulerc and .version files found during modulefile
	    seeking.

.fi
.SS Command line switches
.LP
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 
\fImodule\fP behavior in case of locating and interpreting module files.
.LP
All switches may be entered either in short or long notation. The following
switches are accepted:
.PP
.TP
.I --help, -H
Give some helpful usage information, and terminates the command.
.RS
.RE
.TP
.I --version, -V
Lists the current version of the module command, and some configured
option values.  The command then terminates without further processing.
.RS
.RE
.TP
.I --force, -f
Force active dependency resolution. This will result in modules found on a
\fIprereq\fP command inside a module file being load automatically.
Unloading module files using this switch will result in all required modules
which have been loaded automatically using the \fI-f\fP switch being unload.
This switch is experimental at the moment.
.RS
.RE
.TP
.I --terse, -t
Display \fIavail\fP and \fIlist\fP output in short format.
.RS
.RE
.TP
.I --long, -l
Display \fIavail\fP and \fIlist\fP output in long format.
.RS
.RE
.TP
.I --human, -h
Display short output of the \fIavail\fP and \fIlist\fP commands in human
readable format. 
.RS
.RE
.TP
.I --verbose, -v
Enable verbose messages during module command execution.
.RS
.RE
.TP
.I --silent, -s
Disable verbose messages. Redirect \fIstderr\fP to \fI/dev/null\fP if 
\fIstderr\fP is found not to be a tty. This is a useful option for module
commands being written into \fI.cshrc\fP, \fI.login\fP or \fI.profile\fP
files, because some remote shells (as \fIrsh\fP(1)) and remote execution
commands (like \fIrdist\fP) get confused if there is output on stderr.
.RS
.RE
.TP
.I --create, -c
Create caches for \fImodule avail\fP and \fImodule apropos\fP. You must 
be granted write access to the ${\s-1MODULEHOME\s0}/modulefiles/ directory
if you try to invoke \fImodule\fP with the \fI-c\fP option.
.RS
.RE
.TP
.I --icase, -i
Case insensitive module parameter evaluation. Currently only implemented for
the \fImodule apropos\fP command.
.RS
.RE
.TP
.I --userlvl <lvl>, -u <lvl>
Set the user level to the specified value. The argument of this option may
be one of:
.LP
.I novice, nov
Novice
.LP
.I expert, exp
Experienced module user
.LP
.I advanced, adv
Advanced module user
.SS Module Sub-Commands
.RS
.TP 15
.B help [modulefile...]
Print the usage of each sub-command.
If an argument is given, print the Module specific help information for the
.I modulefile.
.TP 15
.B load modulefile [modulefile...]
.PD 0
.TP 15
.B add modulefile [modulefile...]
.PD
Load
.I modulefile
into the shell environment.
.TP 15
.B unload modulefile [modulefile...]
.PD 0
.TP 15
.B rm modulefile [modulefile...]
.PD
Remove
.I modulefile
from the shell environment.
.TP 15
.B switch [ modulefile1 ] modulefile2
.PD 0
.TP 15
.B swap [ modulefile1 ] modulefile2
.PD
Switch loaded
.I modulefile1
with
.I modulefile2.
If 
.I modulefile1
is not specified, then it is assumed to be the currently loaded module
with the same root name as modulefile2.
.TP 15
.B display modulefile [modulefile...]
.PD 0
.TP 15
.B show modulefile [modulefile...]
.PD
Display information about a
.I modulefile.
The display sub-command will list the full path of the
.I modulefile
and all (or most) of the environment changes the
.I modulefile
will make if loaded.  (It will not display any
environment changes found within conditional statements.)
.TP 15
.B list
List loaded modules.
.TP 15
.B avail [path...]
List all available
.I modulefiles
.hy 0
in the current \s-1MODULEPATH\s0.
All directories in the \s-1MODULEPATH\s0 are recursively searched for
files containing the
.I modulefile
magic cookie.
If an argument is given, then each directory in the \s-1MODULEPATH\s0 is
searched for 
.I modulefiles
whose pathname match the argument.
Multiple versions of an application can be supported by creating a
subdirectory for the application containing
.I modulefiles
for each version.
.TP 15
.B use directory [directory...]
.PD 0
.TP 15
.B use [-a|--append] directory [directory...]
.PD
Prepend directory to the \s-1MODULEPATH\s0 environment variable.
The --append flag will append the directory to \s-1MODULEPATH\s0.
.TP 15
.B unuse directory [directory...]
Remove directory from the \s-1MODULEPATH\s0 environment variable.
.TP 15
.B update
Attempt to reload all loaded
.I modulefiles.
The environment will be reconfigured to match the environment saved in
.I ${\s-1HOME\s0}/.modulesbeginenv
(if BEGINENV=1)
or the file pointed at by
.I $MODULESBEGINEV
(if BEGINENV=99)
and the modulefiles will be reloaded.

This is only valid if modules was configured with --enable-beginenv
(which defines BEGINENV)
else this will cause a warning.
.B update
will only change the environment variables that the
.I modulefiles
set.
.TP 15
.B clear
Force the Modules Package to believe that no modules are currently loaded.
.TP 15
.B purge
Unload all loaded
.I modulefiles.
.TP 15
.B whatis [modulefile [modulefile...]]
Display the modulefile information set up by the \fImodule-whatis\fP commands
inside the specified modulefiles. If no modulefiles are specified all whatis
information lines will be shown.
.TP 15
.B apropos string
.PD 0
.TP 15
.B keyword string
Seeks thru the whatis informations of all modulefiles for the specified string.
All module whatis informations matching the string search will be displayed.
.TP 15
.B initadd modulefile [modulefile...]
Add
.I modulefile
to the shell's initialization file in the user's home directory.
The startup files checked (in order) are:
.br
csh - .modules, .cshrc(.ext), .csh_variables, and .login(.ext)
.br
tcsh - .modules, .tcshrc, .cshrc(.ext), .csh_variables, and .login(.ext)
.br
sh and ksh - .modules, .profile(.ext), and .kshenv(.ext)
.br
bash - .modules, .bash_profile, .bash_login, .profile(.ext), and .bashrc(.ext)
.br
zsh - .modules, .zcshrc(.ext), .zshenv(.ext), and .zlogin(.ext)

If a 'module load' line is found in any of these files, the
.I modulefile(s)
is(are) appended to any existing list of 
.I 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.
.TP 15
.B initprepend modulefile [modulefile...]
Does the same as
.B initadd
but prepends the given modules to the beginning of the list.
.TP 15
.B initrm modulefile [modulefile...]
Remove
.I modulefile
from the shell's initialization files.
.TP 15
.B initswitch modulefile1 modulefile2
Switch
.I modulefile1
with
.I modulefile2
in the shell's initialization files.
.TP 15
.B initlist
List all of the
.I modulefiles
loaded from the shell's initialization file.
.TP 15
.B initclear
Clear all of the 
.I modulefiles
from the shell's initialization files.
.RE
.SS Modulefiles
.LP
.I modulefiles
are written in the Tool Command Language (Tcl) and are interpreted by
.B modulecmd.
.I modulefiles
can use conditional statements.
Thus the effect a 
.I modulefile
will have on the environment may change depending upon the current state of
the environment.
.LP
Environment variables are unset when unloading a
.I modulefile.
Thus, it is possible to
.B load
a 
.I modulefile
and then
.B unload
it without having the environment variables return to their
prior state.
.LP
.SH ENVIRONMENT
.TP
.SB \s-1MODULESHOME\s0
The location of the master Modules package file directory containing
.B module
command initialization scripts, the executable program
.B modulecmd,
and a directory containing a collection of master
.I modulefiles.
.TP
.SB \s-1MODULEPATH\s0
The path that the
.B module
command searches when looking for
.I modulefiles.
Typically, it is set to a default value by the bootstrap procedure.
\s-1MODULEPATH\s0 can be set using 'module use' or by the module
initialization script to search group or personal
.I modulefile
directories before or after the master
.I modulefile
directory.
.TP
.SB \s-1LOADEDMODULES\s0
A colon separated list of all loaded
.I modulefiles.
.TP
.SB \s-1_LMFILES_\s0
A colon separated list of the full pathname for all loaded
.I modulefiles.
.TP
.SB \s-1MODULESBEGINENV\s0
If modules has been configured (BEGINENV=99) to test for this environment
variable, then if it exists, it is the name of the file to store the
the initial shell environment.  This environment variable will have
embedded environment variables unrolled to one level.  The contents of
this variable is only used the first time
.I modules
is invoked.
.TP
.SB \s-1_MODULESBEGINENV_\s0
The filename of the file containing the initialization environment snapshot.

.SH FILES
.TP
.B @prefix@
The \s-1MODULESHOME\s0 directory.
.TP
.B ${\s-1MODULESHOME\s0}/etc/rc
The system-wide
.I modules rc file.
The location of this file can be changed using
the \s-1MODULERCFILE\s0 environment variable as described above.
.TP
.B ${\s-1HOME\s0}/.modulerc
The user specific 
.I modules rc file.
.TP
.B ${\s-1MODULESHOME\s0}/modulefiles
The directory for system-wide
.I modulefiles.
The location of the directory can be changed using
the \s-1MODULEPATH\s0 environment variable as described above.
.TP
.B ${\s-1MODULESHOME\s0}/bin/modulecmd
The 
.I modulefile
interpreter that gets executed upon each invocation of
.B module.
.TP
.B ${\s-1MODULESHOME\s0}/init/\fI<shell>\fP
The Modules package initialization file sourced into the user's
environment.
.TP
.B ${\s-1MODULEPATH\s0}/.moduleavailcache
File containing the cached list of all
.I modulefiles
for each directory in the \s-1MODULEPATH\s0
(only when the avail cache is enabled via the configure option --enable-cache
which sets CACHE_AVAIL).
.TP
.B ${\s-1MODULEPATH\s0}/.moduleavailcachedir
File containing the names and modification times for all sub-directories with
an avail cache (see above).
.TP
.B ${\s-1HOME\s0}/.modulesbeginenv
A snapshot of the user's environment taken at Module initialization.
This information is used by the
.B module update
sub-command (if BEGINENV=1), else
.TP
.B $MODULESBEGINENV
If this defines a valid filename, this serves the same purpose as above
(if BEGINENV=99).
.SH SEE ALSO
.BR modulefile(4)