Running dwalk with --help exits with an error code (1) instead of 0

If you actually ask for --help with dwalk it returns an error instead of success.

root@40ba26226d78:/mfu# dwalk --help; echo $?

Usage: dwalk [options] <path> ...

Options:
  -i, --input <file>      - read list from file
  -o, --output <file>     - write processed list to file in binary format
  -t, --text              - use with -o; write processed list to file in ascii format
  -l, --lite              - walk file system without stat
  -s, --sort <fields>     - sort output by comma-delimited fields
  -d, --distribution <field>:<separators> 
                          - print distribution by field
  -f, --file_histogram    - print default size distribution of items
  -p, --print             - print files to screen
      --no-atime          - use with -l; do not update the file last access time
  -L, --dereference       - follow symbolic links
      --progress <N>      - print progress every N seconds
  -v, --verbose           - verbose output
  -q, --quiet             - quiet output
  -h, --help              - print usage

Fields: name,user,group,uid,gid,atime,mtime,ctime,size
For more information see https://mpifileutils.readthedocs.io. 

1

Start at the dwalk command-line entry point and trace the --help option handling. Run dwalk --help; echo $? before and after the change. Done means the usage text still appears and the command exits with status 0.