A call to oft2-snapshots has the following syntax:
Usage: otf2-snapshots [OPTION]... ANCHORFILE
Append snapshots to existing otf2 traces at given 'break' timestamps.

Options:
  -n, --number <BREAKS> Number of breaks (distributed regularly)
                        if -p and -t are not set, the default for -n is 10
                        breaks.
  -p <TICK_RATE>        Create break every <TICK_RATE> ticks
                        if both, -n and -p are specified the one producing
                        more breaks wins.
      --progress        Brief mode, print progress information.
      --verbose         Verbose mode, print break timestamps, i.e. snapshot
                        informations to stdout.
  -V, --version         Print version information.
  -h, --help            Print this help information.