Provided by: gromacs-data_2025.2-1_all bug

NAME
       gmx-trjcat - Concatenate trajectory files


SYNOPSIS
          gmx trjcat [-f [<.xtc/.trr/...> [...]]] [-n [<.ndx>]] [-demux [<.xvg>]]
                     [-o [<.xtc/.trr/...> [...]]] [-tu <enum>] [-xvg <enum>]
                     [-b <time>] [-e <time>] [-dt <time>] [-[no]settime]
                     [-[no]sort] [-[no]keeplast] [-[no]overwrite] [-[no]cat]


DESCRIPTION
       gmx  trjcat  concatenates  several input trajectory files in sorted order.  In case of double time frames
       the one in the later file is used.  By specifying -settime you will be asked for the start time  of  each
       file.  The  input  files are taken from the command line, such that a command like gmx trjcat -f *.trr -o
       fixed.trr should do the trick. Using -cat, you can simply paste several files together without removal of
       frames with identical time stamps.

       One important option is inferred when the output file is amongst the  input  files.  In  that  case  that
       particular  file  will  be  appended to which implies you do not need to store double the amount of data.
       Obviously the file to append to has to be the one with lowest starting time since one can only append  at
       the end of a file.

       If  the  -demux  option  is  given,  the  N  trajectories  that are read, are written in another order as
       specified in the .xvg file.  The .xvg file should contain something like:

          0  0  1  2  3  4  5
          2  1  0  2  3  5  4

       The first number  is  the  time,  and  subsequent  numbers  point  to  trajectory  indices.   The  frames
       corresponding  to  the numbers present at the first line are collected into the output trajectory. If the
       number of frames in the trajectory does not match that in the .xvg file then  the  program  tries  to  be
       smart. Beware.


OPTIONS
       Options to specify input files:

       -f [<.xtc/.trr/...> [...]] (traj.xtc)
              Trajectory: xtc trr cpt gro g96 pdb tng

       -n [<.ndx>] (index.ndx) (Optional)
              Index file

       -demux [<.xvg>] (remd.xvg) (Optional)
              xvgr/xmgr file

       Options to specify output files:

       -o [<.xtc/.trr/...> [...]] (trajout.xtc)
              Trajectory: xtc trr gro g96 pdb tng

       Other options:

       -tu <enum> (ps)
              Unit for time values: fs, ps, ns, us, ms, s

       -xvg <enum> (xmgrace)
              xvg plot formatting: xmgrace, xmgr, none

       -b <time> (-1)
              First time to use (ps)

       -e <time> (-1)
              Last time to use (ps)

       -dt <time> (0)
              Only write frame when t MOD dt = first time (ps)

       -[no]settime (no)
              Change starting time interactively

       -[no]sort (yes)
              Sort trajectory files (not frames)

       -[no]keeplast (no)
              Keep overlapping frames at end of trajectory

       -[no]overwrite (no)
              Overwrite overlapping frames during appending

       -[no]cat (no)
              Do not discard double time frames


SEE ALSO
       gmx(1)

       More information about GROMACS is available at <http://www.gromacs.org/>.


COPYRIGHT
       2025, GROMACS development team

2025.2                                            May 12, 2025                                     GMX-TRJCAT(1)