---
name: "lamnodes"
section: "1"
platform: "linux"
package: "lam-runtime"
version: "7.1.4-7.2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/lamnodes"
---

# lamnodes(1)

Resolve LAM node/CPU notation to Unix hostnames.

## NAME

lamnodes - Resolve LAM node/CPU notation to Unix hostnames.

## SYNOPSIS

lamnodes \[-chin\] \[where\]

## OPTIONS

- **-c**

  Suppress printing the CPU count for each node.

- **-h**

  Print the command help menu.

- **-i**

  Print IP addresses (instead of IP names)

- **-n**

  Suppress printing CPU count for each node

## DESCRIPTION

The  *lamnodes* command is used to resolve LAM node/CPU nomenclature to Unix hostnames.  It can be used to determine the current running configuration of the LAM/MPI run-time environment, and generate a boot schema that can be used to launch LAM in the future.

By default,  *lamnodes* will print out the node number, default IP name, CPU count, and per-node flags for each node in the running LAM.  [gethostbyaddr(3)](/gethostbyaddr/3.md) is used to obtain default hostnames.  If [gethostbyaddr(3)](/gethostbyaddr/3.md) fails, the IP number is displayed instead.

This command can be used by setup shell scripts (and the like) to determine information from a currently-running LAM universe.  For example, use lamnodes to resolve particular CPUs and/or nodes to specific unix hostnames.  In a batch environment, *lamnodes* can be used to determine which CPUs share a common node (note that MPI\_GET\_PROCESSOR\_NAME can be used for a similar effect in an MPI program).

*lamnodes* also shows per-node flags.  Currently defined flags are:

- **origin**

  The node where  *lamboot* was executed.

- **this\_node**

  The node where *lamnodes* is running.

- **no\_schedule**

  The node will not be used to run MPI and serial processes when N and C are used to *mpirun* and *lamexec*.

## EXAMPLES

- lamnodes N -n

  Display IP names and CPU counts for all nodes.  This output can be saved and later used with [lamboot(1)](/lamboot/1.md).

- lamnodes C -n -c

  Display the IP name of the nodes containing each CPU, and suppress the LAM node number and CPU count.  This output can be saved and later used with [lamboot(1)](/lamboot/1.md).

## SEE ALSO

[bhost(5)](/bhost/5.md), [gethostbyaddr(3)](/gethostbyaddr/3.md), [lamboot(1)](/lamboot/1.md)