NAME

       nodeattr - query genders file

SYNOPSIS

       nodeattr [-f genders] [-q | -c | -n | -s] [-X exclude_query] query
       nodeattr [-f genders] [-q | -c | -n | -s] -A
       nodeattr [-f genders] [-v] [node] attr[=val]
       nodeattr [-f genders] -Q [node] query
       nodeattr [-f genders] -V [-U] attr
       nodeattr [-f genders] -l [node]
       nodeattr [-f genders] -k
       nodeattr [-f genders] -d genders
       nodeattr [-f genders] --expand
       nodeattr [-f genders] --compress

DESCRIPTION

       When  invoked with the -q , -c , -n , or -s arguments, nodeattr reads the genders file and
       outputs a list of nodes that match the specified query.  The nodes are listed in  hostlist
       format,  comma  separated  lists,  newline  separated  lists,  or  space  separated  lists
       respectively.  Genders queries will query the genders database for a set of nodes based on
       the  union, intersection, difference, or complement of genders attributes and values.  The
       set operation union is represented  by  two  pipe  symbols  ('||'),  intersection  by  two
       ampersand  symbols  ('&&'),  difference  by  two minus symbols ('--'), and complement by a
       tilde ('~').  Parentheses may be used to change the order of operations.  The -X  argument
       and query can be used to exclude nodes from the resulting output.  A query can be replaced
       with the -A option to cause nodeattr  to  print  all  the  nodes  listed  in  the  genders
       database.

       When  called  with  a  node  name (optional) and attribute name, nodeattr returns 0 to the
       environment if the node has the attribute; else 1.  If -v is present, the  attribute  name
       and  any  value  (see  below)  is  printed  on the standard output.  If a node name is not
       specified, the local host is assumed.

       When called with the -Q argument, nodeattr will check if the node name (optional)  is  met
       by  the attribute and value conditions specified in the query.  If the conditions are met,
       nodeattr returns 0 to the environment; else 1.  The  query  format  is  identical  to  the
       format listed above.  If a node name is not specified, the local host is assumed.

       The  -V  option  causes  nodeattr  to  print all of the values that exist for a particular
       attribute.  Also specifing -U with -V causes nodeattr to print out only unique values  for
       the particular attribute.

       The  -l  option causes nodeattr to print the attributes of the specified node.  If no node
       is listed, all attributes in the genders file are listed.

       The -k option checks the genders file for parse errors and proper formatting.   If  errors
       are found, information about the error will be output to standard error.

       Nodeattr  will  always check the default genders file, but a different genders file can be
       specified with the -f option.

       The -d option allows the specified  genders  database  to  be  compared  to  the  filename
       indicated  by the -f option or the default genders database.  The differences contained in
       the specified database will be output to standard error.

       The --expand option will take a genders database, expand all hostranges, and output a  new
       genders  database.  The subsequent database will be identical to the first, but every node
       will be listed on a separate line.  This option may be useful for debugging or determining
       the difference between databases.

       The --compress is opposite of the --expand option.  It will output a new identical genders
       database with hostranges of nodes with identical attributes.  Depending on  the  setup  of
       your  genders  database, the resulting database may be longer or shorter.  This option may
       be useful as a beginning step to compressing an existing genders database.

       Attribute names may optionally appear in the genders file with an equal sign followed by a
       value.   Nodeattr  ignores these values except when the -v option requests that the value,
       if any, be displayed; and when an attribute is specified on the command line with a value,
       in which case only an attribute with the specified value in the genders file will match.

EXAMPLES

       Retrieve a comma separated list of all login nodes:

              nodeattr -c login

       Retrieve a hostlist formatted list of all login nodes:

              nodeattr -q login

       Retrieve a comma separated list of nodes with 4 cpus:

              nodeattr -c cpus=4

       Retrieve a comma separated list of all login and management nodes:

              nodeattr -c "login||mgmt"

       Retrieve a comma separated list of all login nodes with 4 cpus:

              nodeattr -c "login&&cpus=4"

       Retrieve a comma separated list of all nodes that are not login or management nodes:

              nodeattr -c "~(login||mgmt)"

       To use nodeattr with pdsh to run a command on all fddi nodes:

              pdsh -w`nodeattr -c fddi` command

       To use nodeattr in a ksh script to collect a list of users on login nodes:

              for i in `nodeattr -n login`; do rsh $i who; done

       To verify whether or not this node is a head node:

              nodeattr head && echo yes

       To verify whether or not this node is a head node and ntpserver:

              nodeattr -Q "head&&ntpserver" && echo yes

FILES

       /etc/genders

SEE ALSO

       libgenders(3)