rhash:tldr:f12a3

The command rhash --base64 --bsd ${filename} performs the following actions:

1. rhash is a command-line utility used for generating and verifying various hash sums (such as MD5, SHA-1, SHA-256, etc.) of files.
2. The --base64 option tells rhash to output the hash value in base64 encoding. Base64 encoding is a binary-to-text encoding scheme that represents binary data as ASCII strings.
3. The --bsd option specifies the format used for the output. In this case, the output format will be similar to the traditional BSD checksum format.
4. ${filename} is a placeholder for the name of the file for which you want to calculate the hash sum. You need to replace ${filename} with the actual filename or the path to the file.

To summarize, this command calculates the hash sum (using a default hash algorithm, such as SHA-1) of the specified file and outputs it in base64 encoding, following the BSD checksum format.