EDIT—TABSET subcommand operands

ON(integer_list): specifies tab settings are to be translated into blanks by the system. If you specify ON without an integer list, the existing or default tab settings are used. You can establish new values for tab settings by specifying the numbers of the tab columns as values for the integer list. A maximum of ten values is allowed. ON is the default.
OFF: specifies there is to be no translation of tabulation characters. Each strike of the tab key produces a single blank in the data.
IMAGE: specifies the next input line defines new tabulation settings. The next line that you type should consist of t's, indicating the column positions of the tab settings, and blanks or any other characters except t. Ten is the maximum number of tab settings allowable. Do not use the tab key to produce the new image line. A good practice is to use a sequence of digits between the t's so you can easily determine which columns the tabs are set to (see Example 3).