hostlist(1)

NAME
hostlist - handle hostlist expressions

SYNOPSIS
hostlist [OPTION]... [HOSTLIST]...

DESCRIPTION
Perform a set operation (union, intersection, difference or symmetric difference) on the given hostlists. Output the result as a hostlist, a count of hostnames or an expanded list of hostnames. If "-" is used instead of a hostlist argument, an arbitrary number of hostlists are read from stdin. The union of them is used as if it had been present on the command line as a single hostlist argument.

OPTIONS

-u, --union
    Compute the union of the hostlists. A hostname is present in the output if it is included in at least one of the hostlists. This is the default operation.

-i, --intersection
    Compute the intersection of the hostlists. A hostname is present in the output if it is included in all the hostlists.

-d, --difference
    Compute the difference of the hostlists. A hostname is present in the output if it is included in the first hostlist but not any of the following.

-x, --symmetric-difference
    Compute the symmetric difference of the hostlists. A hostname is present in the output if it is included in an odd number of the hostlists.

-o OFFSET, --offset=OFFSET
    Filter the result to skip OFFSET hosts from the beginning. If OFFSET is not less than the number of hosts in the result, the result will become empty. If OFFSET is negative, keep -OFFSET hosts from the end of the result. The default is to skip nothing.

-l LIMIT, --limit=LIMIT
    Filter the result to limit it to the first LIMIT hosts. If LIMIT is not less than the number of hosts in the result, this option does nothing. This filter is applied after the --offset filter (see above). The default is to have no limit.

-c, --collapse
    Output the result as a hostlist expression. This is the default. See the --chop option for splitting into multiple hostlists of a certain size.

-n, --count
    Output the number of hostnames in the result.

-e, --expand
    Output the result as an expanded list of hostnames.

-w  Output the result as an expanded list of hostnames. This option is deprecated. Use -e or --expand instead.

-q, --quiet
    Output nothing. This option is useful together with --non-empty.

-0, --non-empty
    Return success if the resulting hostlist is non-empty and failure if it is empty.

-s SEPARATOR, --separator=SEPARATOR
    Use SEPARATOR as the separator between the hostnames in the expanded list (and between (chopped) hostlists in collapsed mode). The default is a newline.

-p PREPEND, --prepend=PREPEND
    Output PREPEND before each hostname in the expanded list (and before each hostlist in collapsed mode). The default is to prepend nothing.

-a APPEND, --append=APPEND
    Output APPEND after each hostname in the expanded list (and after each hostlist in collapsed mode). The default is to append nothing.

-S FROM,TO, --substitute=FROM,TO
    Apply a regular expression substitution to each hostname, replacing all FROM with TO. The default is to do no substitution.

--append-slurm-tasks=SLURM_TASKS_PER_NODE
    Append the number of tasks parsed from the SLURM_TASKS_PER_NODE string. You need to use -e/--expand and you probably need to specify -a/--append and -s/--separator too. NOTE: The hostlist is always sorted internally by this program. The task counts from SLURM_TASKS_PER_NODE is then applied to each hostname in the sorted list.

--repeat-slurm-tasks=SLURM_TASKS_PER_NODE
    Repeat each hostname so it is listed multiple times as specified by the SLURM_TASKS_PER_NODE string. You need to use -e/--expand. NOTE: The hostlist is always sorted internally by this program. The task counts from SLURM_TASKS_PER_NODE is then applied to each hostname in the sorted list.

--chop=CHUNKSIZE
    When outputting as collapsed hostlist (the default mode --collapse) split into hostlists of size CHUNKSIZE and output each hostlist separately. The last hostlist may be smaller than the rest.

--version
    Show the version of the utility and the underlying Python library.

EXAMPLES

Output the union of n[10-19] and n[15-24] (which is n[10-24]):
    hostlist n[10-19] n[15-24]

Output the result of removing n15 and n[17-18] from n[1-20] (which is n[1-14,16,19-20]):
    hostlist -d n[1-20] n15 n[17-18]

Output the result as an expanded list of hostnames (one hostname per line):
    hostlist -d -e n[1-20] n15 n[17-18]

Output the result as an expanded list of hostnames separated by commas:
    hostlist -d -e -s, n[1-20] n15 n[17-18]

Output the result as an expanded list of hostnames (followed by space and the digit "8") separated by spaces:
    hostlist -d -e -s " " -a " 8" n[1-20] n15 n[17-18]

Expand a hostlist, replacing "n" with "ni":
    hostlist -e -S n,ni n[1-20]

Print INCLUDED as n11 is in n[10-20]:
    if hostlist -q0 -i n11 n[10-20]; then echo INCLUDED; else echo NOT INCLUDED; fi

AUTHOR
Written by Kent Engström <kent@nsc.liu.se>. The program is published at http://www.nsc.liu.se/~kent/python-hostlist/

NOTES
The square brackets used in the hostlist expression syntax are also used in shell glob patterns. This may cause unwanted surprises if you have files in your current directory named after hosts present in the hostlist. Always quote the hostlist expression to avoid this problem:
  % hostlist n[1-10]
  n[1-10]
  % touch n1
  % hostlist n[1-10]
  n1
  % echo n[1-10]
  n1
  % hostlist "n[1-10]"
  n[1-10]

SEE ALSO
The hostlist expression syntax is used by several programs developed at LLNL (https://computing.llnl.gov/linux/), for example SLURM (https://computing.llnl.gov/linux/slurm/) and Pdsh (https://computing.llnl.gov/linux/pdsh.html). See the HOSTLIST EXPRESSIONS section of the pdsh(1) manual page for a short introduction to the hostlist syntax.