geturl command — LAMMPS documentation

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# geturl command

## Syntax

    geturl url keyword args ...

- url = URL of the file to download

- zero or more keyword argument pairs may be provided

- keyword = output or verify or overwrite or verbose

      output filename = write to filename instead of inferring the name from the URL
      verify yes/no = verify SSL certificate and hostname if yes, do not if no
      overwrite yes/no = if yes overwrite the output file in case it exists, do not if no
      verbose yes/no = if yes write verbose debug output from libcurl to screen, do not if no

## Examples

    geturl https://www.ctcms.nist.gov/potentials/Download/1990--Ackland-G-J-Vitek-V--Cu/2/Cu2.eam.fs
    geturl https://github.com/lammps/lammps/blob/develop/bench/in.lj output in.bench-lj

## Description

Added in version 29Aug2024.

Download a file from an URL to the local disk. This is implemented with the libcurl library which supports a large variety of protocols including “http”, “https”, “ftp”, “scp”, “sftp”, “file”. The transfer will only be performed on MPI rank 0.

The output keyword can be used to set the filename. By default, the last part of the URL is used.

The verify keyword determines whether `libcurl` will validate the SSL certificate and hostname for encrypted connections. Turning this off may be required when using a proxy or connecting to a server with a self-signed SSL certificate.

The overwrite keyword determines whether a file should be overwritten if it already exists. If the argument is no, then the download will be skipped if the file exists.

The verbose keyword determines whether a detailed protocol of the steps performed by libcurl is written to the screen. Using the argument yes can be used to debug connection issues when the geturl command does not behave as expected. If the argument is no, geturl will operate silently and only report the error status number provided by libcurl, in case of a failure.

## Restrictions

This command is part of the EXTRA-COMMAND package. It is only enabled if LAMMPS was built with that package. See the Build package page for more info. It also requires that LAMMPS was built with support for the libcurl library. See the page about Compiling LAMMPS with libcurl support for further info. If support for libcurl is not included, using geturl will trigger an error.

## Related commands

shell

## Default

verify = yes, overwrite = yes