Mas var

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Template:Hierarchy header mas_var is a program for determining MAS configuration information (especially paths to scripts, data directories, and other configuration files). It was developed to replace the environment-based approach that existed previously, especially for systems using Multicard MAS where more than one fibre card is in use. mas_var queries the mas.cfg configuration file to get the system configuration.

Legacy, single fibre card installations may ignore the availability of mas_var, and simply use MAS_* environmental variables as before without issue. Multicard MAS users will find such an approach difficult.

For a more detailed discussion of environmental variables themselves, see the Environmental variables page.

Usage

Running mas_var without any options will produce a usage summary. In general, mas_var is invoked as: 

mas_var [OPTION]... [PARAMETER]...

The options are: 

  -c                print C shell commands for regularising the environment for
                      the specified (or default) MCE device. (See below for an
                      example of use.)
  -e                ignore any MAS_... environment variables.
  -m <file>         read MAS configuration from the specified file instead of
                      the default mas.cfg (the one reported by --config-file)
  -n <card>         report values for the specified fibre card.  Ignored if not
                      running Multicard MAS.
  -Q                quiet: don't write warnings.
  -q                instead of reporting the value on standard output, exit with
                      non-zero status if the first parameter is false, otherwise
                      exit with zero status.  Only makes sense with a boolean
                      parameter: all other parameters are implicitly true.
  -s                print Bourne-compatible shell commands for regularising the 
                      environment for the specified (or default) MCE device.
                      (See below for an example of use.)
  -x                when used with -c or -s, only define required environmental
                      variables, specifically: MAS_MCE_DEV, MAS_PREFIX, and
                      MAS_VAR, plus modified PATH and PYTHONPATH.  If -e is also
                      specified, the commands output will remove all other MAS
                      variables from the environment.  Ignored if not used
                      with -c or -s, and when not running Multicard MAS.

The parameters are: 

  --bigphys         boolean; true if the driver supports bigphysarea
  --bin-dir         the location of the MAS binaries (MAS_BIN in the
                      environment)
  --cflags          cc(1) options needed to complile against the MAS libraries
  --config-dir      the location of the MCE config files (MAS_CONFIG in the
                      environment)
  --config-file     the full path of the default MAS configuration file
  --data-dir        the current data directory (MAS_DATA in theenvironment)
  --data-root       the root data directory (MAS_DATA_ROOT in the environment)
  --etc-dir         the directory containing the hardware description files
                      (MAS_ETC in the environment.)
  --experiment-file the full path of the experiment configuration file
  --fakemce         boolean; true if the driver contains the facemce device
  --fibre-card      the number of the current fibre card
  --group           the MAS group
  --hardware-file   the full path of the hardware configuration file
  --idl-dir         the MCE script IDL directory (MAS_IDL in the environment)
  --jam-dir         the location of the JAM firmware files (MAS_JAM_DIR in the
                      environment)
  --libs            ld(1) options needed to link to the MAS libraries
  --mas-root        the base directory for the MCE script tree (MAS_ROOT
                      in the environment)
  --max-fibre-card  the maximum number of fibre cards supported
  --multicard       booelan; true if MAS supports multiple fibre cards
  --path[=PATHBASE] a shell PATH variable for MAS.  If given, MAS specific
                      directories will be appended to PATHBASE, otherwise they
                      will be appended to the current PATH.  (See also
                      --path-base below.)
  --path-base       the current PATH variable stripped of any directories which
                      start with the MAS prefix (see --prefix) or the MAS_ROOT
                      environment variable, if it is defined.  The value is
                      suitable for providing to --path.
  --prefix          the MAS prefix
  --pythonpath[=PATHBASE]
                    a PYTHONPATH variable for MAS.  If given, MAS specific
                      directories will be appended to PATHBASE, otherwise they
                      will be appended to the current PYTHONPATH.  (See also
                      --pythonpath-base below.)
  --pythonpath-base the current PYTHONPATH variable stripped of any directories
                      which start with the MAS prefix (see --prefix) or the
                      MAS_ROOT environment variable, if it is defined.  The
                      value is suitable for providing to --pythonpath.
  --python-dir      the MCE script python directory (MAS_PYTHON in the
                      environment)
  --script-dir      the MCE script directory (MAS_SCRIPT in the environment)
  --temp-dir        the MAS temporary directory (MAS_TEMP in the environment)
  --template-dir    the MAS template directory (MAS_TEMPLATE in the environment)
  --test-suite      the MAS test suite directory (MAS_TEST_SUITE in the
                      environment)
  --user            the MAS username
  --version         the mas_var version

Examples

  • Unless -q, -c, or -s is specified, mas_var will print the value of each parameter listed, one per line, in the order given on the command line:
 user@ubuntu:~$ mas_var --version --user --prefix --mas-root --data-dir
 MAS/trunk/739
 mce
 /usr/mce
 /usr/mce/mce_script
 /data/cryo/current_data
  • If -q is specified, mas_var prints nothing but exits with non-zero status if the first parameter is false. This only makes sense with boolean parameters (--bigphys or --fakemce):
 user@ubuntu:~$ mas_var --fakemce --bigphys
 False
 True
 user@ubuntu:-$ if mas_var -q --bigphys; then echo "Bigphys enabled"; else echo "Bigphys disabled"; fi
 Bigphys enabled
 user@ubuntu:-$ if mas_var -q --fakemce; then echo "FakeMCE present"; else echo "FakeMCE absent"; fi
 FakeMCE absent
  • If -m is used to specify a different mas.cfg file, results will change to reflect the different MAS configuration:
 user@ubuntu:~$ mas_var --etc-dir
 /etc/mce
 user@ubuntu:~$ grep etcdir ~/mas.cfg
 etcdir = "/usr/local/etc/mce";
 user@ubuntu:~$ mas_var -m ~/mas.cfg --etc-dir
 /usr/local/etc/mce
Perhaps surprisingly, the exception to this is the --config-file parameter (which reports the location of mas.cfg). It ignores -m completely and always reports the default mas.cfg location:
 user@ubuntu:~$ mas_var --config-file
 /etc/mce/mas.cfg
 user@ubuntu:~$ mas_var -m ~/mas.cfg --config-file
 /etc/mce/mas.cfg
(this is because a default mas.cfg path is hard-coded into the MAS library at build time to resolve the chicken-and-egg problem of having to read mas.cfg to determine the location of mas.cfg). See also the MAS_MAS_CFG environmental variable.
  • If -s is given, Bourne-compatible shell commands are printed for "regularising" the environment:
 user@ubuntu:~$ mas_var -s
 export MAS_VAR="/usr/mce/bin/mas_var";
 export MAS_MCE_DEV="0";
 export MAS_PREFIX="/usr/mce";
 export MAS_ROOT="/usr/mce/mce_script";
 
 export MAS_BIN="/usr/mce/bin";
 export MAS_CONFIG="/usr/mce/config";
 export MAS_JAM_DIR="/usr/mce/firmware";
 export MAS_TEMP="/tmp";
 export MAS_DATA_ROOT="/data/cryo";
 export MAS_DATA="/data/cryo/current_data";
 
 export MAS_IDL="/usr/mce/mce_script/idl_pro";
 export MAS_PYTHON="/usr/mce/mce_script/python";
 export MAS_SCRIPT="/usr/mce/mce_script/script";
 export MAS_TEMPLATE="/usr/mce/mce_script/template";
 export MAS_TEST_SUITE="/usr/mce/mce_script/test_suite";
 
 export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/mce/bin:/usr/mce/mce_script/script:/usr/mce/mce_script/test_suite";
 export PYTHONPATH="/usr/mce/mce_script/python:/usr/mce/python";
Similarly, in the C Shell, -c can be used. If MAS_... environmental variables are already defined, they will be left unchanged, simply repeated in the output, unless -e is also specified, telling mas_var to ignore the current environment. In Multicard MAS, if -x is specified along with -s or -c, only a minimal set of environmental variables will be set. This can be advantageous in certain situations; see the discussion in Multicard MAS for details.
These options (-s and -c) are most useful when mas_var is run inside back-ticks (`) and the output sent through eval to update the currently executing shell's environment; see below.

mas_var as a replacement for the MAS environment variables

The scripts and tuning programs no longer require that the $MAS_* environment variables be defined. Instead, they will run mas_var to determine the necessary paths, based on information in mas.cfg. If $MAS_VAR is defined, that is assumed to be the path to mas_var, otherwise /usr/mce/bin/mas_var is used.

The standard MAS environment variables can be set using mas_var

When running from the command line it is sometimes convenient to have the $MAS_* variables defined, and to update $PATH and $PYTHONPATH for the MAS software. To achieve this in bash, run: 

eval `mas_var -e -s`

(note the back ticks). This line can be put in a user's .bashrc, to be run at login as a replacement for the older "source $MAS_ROOT/template/mas_env.bash".

Environment variables override the settings in mas.cfg

Note that environment variables can be used to override the settings in mas.cfg -- this can be useful in cases where one would like to temporarily switch script trees or data directories: 

user@ubuntu:~$ mas_var --script-dir
/usr/mce/mce_script/script
user@ubuntu:~$ export MAS_SCRIPT=/home/user/code/mce_script/script
user@ubuntu:~$ mas_var --script-dir
/home/user/code/mce_script/script

Because the MCE scripts obtain paths through mas_var, the environmental override with be propagated to them as well.

The -e option disables this behaviour, making mas_var ignore the environment: 

user@ubuntu:~$ export MAS_SCRIPT=/home/user/code/mce_script/script
user@ubuntu:~$ mas_var --script-dir
/home/user/code/mce_script/script
user@ubuntu:~$ mas_var -e --script-dir
/usr/mce/mce_script/script
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