sorting of atoms

I have used a dump atoms command to dump a txt file.Now I want to sort the atomIDs in the file. So I used
dump 1 all atom 100 dump.run.txt
dump_modify 1 sort atom ID

But I am getting an error message:Expected integer parameter in input script or data file (…/dump.cpp:856)

The sorting of the atoms are very essential for my work. So please help.

From the doc page:

*sort* arg = *off* or *id* or N or -N
     off = no sorting of per-atom lines within a snapshot
     id = sort per-atom lines by atom ID
     N = sort per-atom lines in ascending order by the Nth column
     -N = sort per-atom lines in descending order by the Nth column
Ray

I have used a dump atoms command to dump a txt file.Now I want to sort the
atomIDs in the file. So I used
dump 1 all atom 100 dump.run.txt
dump_modify 1 sort atom ID
But I am getting an error message:Expected integer parameter in input script
or data file (../dump.cpp:856)
The sorting of the atoms are very essential for my work. So please help.

please note: ID != id

Got it.Thank you very much.

Many thanks sir.I have changed it and its working now.