# Gmx: not found

**URL:** <https://gromacs.bioexcel.eu/t/gmx-not-found/3061>\
**Category:** User discussions\
**Created:** [November 1, 2021, 1:02pm UTC](https://gromacs.bioexcel.eu/t/gmx-not-found/3061 "2021-11-01T13:02:59Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![asker1](https://avatars.discourse-cdn.com/v4/letter/a/e0b2c6/32.png) [@asker1](https://gromacs.bioexcel.eu/u/asker1)\
**Post date:** [November 1, 2021, 1:02pm UTC](https://gromacs.bioexcel.eu/t/gmx-not-found/3061/1 "2021-11-01T13:02:59Z")

</div>

GROMACS version: 2020.4  
i got this problem

> gmx: not found

the code is

```auto
for i in 0 .. 35 $
do
gmx grompp -f nvt_$i.mdp -c em.gro -p topol.top -o remd_$i.tpr 
done 
gmx -np 37 -v -deffnm remd -multidir sim1... sim35 -replex 500 >> remd.log

```

while i installed gromax and tested the command gmx and got

```auto
 :-) GROMACS - gmx, 2020.4 (-:

                            GROMACS is written by:
     Emile Apol Rossen Apostolov Paul Bauer Herman J.C. Berendsen
    Par Bjelkmar Christian Blau Viacheslav Bolnykh Kevin Boyd    
 Aldert van Buuren Rudi van Drunen Anton Feenstra Alan Gray     
  Gerrit Groenhof Anca Hamuraru Vincent Hindriksen M. Eric Irrgang  
  Aleksei Iupinov Christoph Junghans Joe Jordan Dimitrios Karkoulis
    Peter Kasson Jiri Kraus Carsten Kutzner Per Larsson    
  Justin A. Lemkul Viveca Lindahl Magnus Lundborg Erik Marklund   
    Pascal Merz Pieter Meulenhoff Teemu Murtola Szilard Pall   
    Sander Pronk Roland Schulz Michael Shirts Alexey Shvetsov  
   Alfons Sijbers Peter Tieleman Jon Vincent Teemu Virolainen 
 Christian Wennberg Maarten Wolf Artem Zhmurov   
                           and the project leaders:
        Mark Abraham, Berk Hess, Erik Lindahl, and David van der Spoel

Copyright (c) 1991-2000, University of Groningen, The Netherlands.
Copyright (c) 2001-2019, The GROMACS development team at
Uppsala University, Stockholm University and
the Royal Institute of Technology, Sweden.
check out http://www.gromacs.org for more information.

GROMACS is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License
as published by the Free Software Foundation; either version 2.1
of the License, or (at your option) any later version.

GROMACS: gmx, version 2020.4
Executable: /usr/local/gromacs/bin/gmx
Data prefix: /usr/local/gromacs
Working dir: /home/samar
Command line:
  gmx

SYNOPSIS

gmx [-[no]h] [-[no]quiet] [-[no]version] [-[no]copyright] [-nice <int>]
    [-[no]backup]

OPTIONS

Other options:

 -[no]h (no)
           Print help and quit
 -[no]quiet (no)
           Do not print common startup info or quotes
 -[no]version (no)
           Print extended version information and quit
 -[no]copyright (yes)
           Print copyright information on startup
 -nice <int> (19)
           Set the nicelevel (default depends on command)
 -[no]backup (yes)
           Write backups if output files exist

Additional help is available on the following topics:
    commands List of available commands
    selections Selection syntax and usage
To access the help, use 'gmx help <topic>'.
For help on a command, use 'gmx help <command>'.

GROMACS reminds you: "The Poodle Chews It" (F. Zappa)

```

---

<div class="post-metadata">

**Author:** ![alevilla](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/alevilla/32/439_2.png) [@alevilla](https://gromacs.bioexcel.eu/u/alevilla)\
**Post date:** [November 5, 2021, 1:33pm UTC](https://gromacs.bioexcel.eu/t/gmx-not-found/3061/2 "2021-11-05T13:33:59Z")

</div>

Hi,  
It looks like that GROMACS is not source in the terminal where you run the command

> gmx

To source GROMACS

> source /usr/local/gromacs/bin/GMXRC

If GROMACS is not installed in the default dir, substitute `/usr/local/gromacs/` with the appropriate path.  
To source GROMACS by default under linux you can add the source command in your .{yourshell\_type}\_rc file

\Alessandra