# How to get trajectory frame each one nono second?

**URL:** <https://gromacs.bioexcel.eu/t/how-to-get-trajectory-frame-each-one-nono-second/2296>\
**Category:** User discussions\
**Created:** [June 4, 2021, 3:43pm UTC](https://gromacs.bioexcel.eu/t/how-to-get-trajectory-frame-each-one-nono-second/2296 "2021-06-04T15:43:57Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![mj.rezayani](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/mj.rezayani/32/3918_2.png) [@mj.rezayani](https://gromacs.bioexcel.eu/u/mj.rezayani)\
**Post date:** [June 4, 2021, 3:43pm UTC](https://gromacs.bioexcel.eu/t/how-to-get-trajectory-frame-each-one-nono-second/2296/1 "2021-06-04T15:43:57Z")

</div>

Hi,

I want to get trajectory frame each one nano second from 50 to 100 nano seconds. For example, 50,51,52,…  
in separated files. I used `gmx trjconv` with -b 50000 -e 50001 to get one frame. Is there any option to get number of frames each one nano second? I am using bash script to analyze each frame and finally take the average of results but I need just one frame each ns.

Thanks, in advance

---

<div class="post-metadata">

**Author:** ![Masrul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/masrul/32/234_2.png) [@Masrul](https://gromacs.bioexcel.eu/u/Masrul)\
**Post date:** [June 4, 2021, 4:08pm UTC](https://gromacs.bioexcel.eu/t/how-to-get-trajectory-frame-each-one-nono-second/2296/2 "2021-06-04T16:08:33Z")

</div>

Add -dt 1000

---

<div class="post-metadata">

**Author:** ![mj.rezayani](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/mj.rezayani/32/3918_2.png) [@mj.rezayani](https://gromacs.bioexcel.eu/u/mj.rezayani)\
**Post date:** [June 4, 2021, 5:10pm UTC](https://gromacs.bioexcel.eu/t/how-to-get-trajectory-frame-each-one-nono-second/2296/3 "2021-06-04T17:10:20Z")

</div>

Thank you dear Masrul

Is there any way to have each frame in separated files?

---

<div class="post-metadata">

**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [June 4, 2021, 5:23pm UTC](https://gromacs.bioexcel.eu/t/how-to-get-trajectory-frame-each-one-nono-second/2296/4 "2021-06-04T17:23:13Z")

</div>

I would use `-skip` here instead of `-dt`. You can then write each snapshot to its own coordinate file with `-sep`.