q:tldr:3fbc3

This command seems to be using the q program to execute a SQL-like query on a file.

Here is the breakdown of the command:

• q is the name of the program being used.
• -d${delimiter} specifies the delimiter to be used when parsing the file. The ${delimiter} is a placeholder that should be substituted with the actual delimiter value.
• -H is an option that instructs the program to treat the first line of the file as the header and use it to name the columns.
• "SELECT * from ${filename}" is the SQL-like query to be executed. The ${filename} is a placeholder that should be substituted with the actual name of the file to query.

Overall, this command is likely using the q program to query a file using a SQL-like syntax and specified delimiter, treating the first line as the header.