NAME
nodeattr - query genders file
SYNOPSIS
nodeattr [-f genders] [-q | -c | -n | -s] [-X exclude_query] query
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
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.
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.
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)