as: Psize
7.74 '.psize LINES , COLUMNS'
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Use this directive to declare the number of lines--and, optionally, the
number of columns--to use for each page, when generating listings.
If you do not use '.psize', listings use a default line-count of 60.
You may omit the comma and COLUMNS specification; the default width is
200 columns.
'as' generates formfeeds whenever the specified number of lines is
exceeded (or whenever you explicitly request one, using '.eject').
If you specify LINES as '0', no formfeeds are generated save those
explicitly specified with '.eject'.