IBM Aspera HST Admin Manual page 146

• Files that are open for write by another process on a Windows source or destination cannot be transferred and
return a "sharing violation" error. On Unix-like operating systems, files that are open for write by another process
are transferred without reporting an error, but may produce unexpected results depending on what data in the file
is changed and when relative to the transfer.
Environment Variables
If needed, you can set the following environment variables for use with an ascp4 session. The total size for
environment variables depends on your operating system and transfer session. Aspera recommends that each
environment variable value should not exceed 4096 characters.
ASPERA_SCP_PASS=password
The password that is used for SSH authentication of the transfer user.
ASPERA_SCP_TOKEN=token
Set the transfer user authorization token. Ascp 4 currently supports transfer tokens, which must
be created by using astokengen with the --full-paths option. For more information, see
Transfer Token Generation (astokengen)
ASPERA_SCP_COOKIE=cookie
A cookie string that is passed to monitoring services.
ASPERA_SRC_PASS=password
The password that is used to authenticate to a URI source.
ASPERA_DST_PASS=password
Set the password that is used to authenticate to a URI destination.
Ascp 4 Options
-A, --version
Display version and license information.
-c {aes128|aes192|aes256|none}
Encrypt in-transit file data using the specified cipher. This option overrides the
<encryption_cipher> setting in aspera.conf.
--check-sshfp=fingerprint
Compare fingerprint to the server SSH host key fingerprint that is set with
<ssh_host_key_fingerprint> in aspera.conf. Aspera fingerprint convention is to use
a hex string without the colons; for example, f74e5de9ed0d62feaf0616ed1e851133c42a0082. For
more information on SSH host key fingerprints, see
--chunk-size=bytes
Perform storage read/write operations with the specified buffer size. Also use the buffer size as an
internal transmission and compression block. Valid range: 4 KB - 128 MB. For transfers with object
storage, use --chunk-size=1048576 if chunk size is not configured on the server to ensure
that the chunk size of ascp4 and Trapd match.
--compare={size|size+mtime|md5|md5-sparse|sha1|sha1-sparse}method
When using --overwrite and --resume, compare files with the specified method. If the --
overwrite method is diff or diff+older, the default --compare method is size.
--compression={none|zlib|lz4}
Compress file data inline. Default: lz4. If set to zlib, --compression-hint can be used to
set the compression level.
--compression-hint=num
Compress file data to the specified level when --compression is set to an option that accepts
compression level settings (currently only zlib). A lower value results in less, but faster, data
| ascp4: Transferring from the Command Line with Ascp 4 | 146
on page 293.
Securing Your SSH Server on page 16.